UBC Theses and Dissertations

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UBC Theses and Dissertations

A comparative study of breeding ecology and timing in plankton-feeding alcids (Cychlorrhynchus and Aethia… Sealy, Spencer George 1968

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COMPARATIVE STUDY OF BREEDING ECOLOGY AND TIMING IN PLANKTON-FEEDING ALCIDS (CYCHLORRHYNCHUS AND AETHIA SPP.) ON ST. LAWRENCE ISLAND, ALASKA BY SPENCER GEORGE SEALY B . S c , U n i v e r s i t y o f A l b e r t a , 1964 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE i n t h e Department o f Zoology We a c c e p t t h i s t h e s i s as c o n f o r m i n g t o t h e r e q u i r e d s t a n d a r d THE UNIVERSITY OF BRITISH COLUMBIA A p r i l , 1968 In presenting t h i s t h e s i s in p a r t i a l f u l f i l m e n t of the requirements f o r an advanced degree at the U n i v e r s i t y of B r i t i s h Columbia, I agree that the L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r reference and study. I f u r t h e r agree that permission f o r extensive copying of t h i s t h e s i s f o r s c h o l a r l y purposes may be granted by the Head of my Department or by h i s represen-t a t i v e s . It i s understood that copying or p u b l i c a t i o n of t h i s t h e s i s f o r f i n a n c i a l gain s h a l l not be allowed without my w r i t t e n permission. Department nf The U n i v e r s i t y of B r i t i s h Columbia Vancouver 8, Canada Date ABSTRACT A comparative study of breeding ecology in Parakeet Auklets (Cychlorrhynchus p s i t t a c u l a (Pallas)), Crested Auklets (Aethia c r i s t a t e l l a (Pallas)), and Least Auklets (A. p u s i l l a (Pallas)) was conducted on St. Lawrence Island, Alaska, in 1966 and 1967. Emphasis was placed upon the cl i m a t i c conditions which prevailed throughout the breeding seasons and the i r e f f e c t s on timing of breeding in auklets. The pre-egg stage, egg-laying and incubation, hatching, growth of young, and departure of chicks were studied in both seasons; 1966 was a late year and 1967 was an early year. It was found that (1) Parakeet Auklets appear to have a more extensive migration than Aethia spp. , (2) a r r i v a l of adults back on the breeding grounds in spring occurs at approximately mid-May each year, (3) the pre-egg stage i s prolonged but the post-breeding d i s p e r s a l of adults and young from the nesting slope i s rapid, (4) breeding does not take place at the same time each year, (5) Cychlorrhynchus breeds a few days l a t e r than.Aethia spp., (6) a change in d i e t accompanies the onset of the chick-rearing period in Aethia spp. but not in Cych1orrhynchus, (7) patterns and rates of g r o w t h o f A. p u s i l l a c h i c k s a n d p o s s i b l y c h i c k s o f C y c h l o r r h y n c h u s a n d A. c r i s t a t e l l a d i f f e r a c c o r d i n g t o t i m e o f h a t c h i n g , (8) c h i c k s o f t h e s e a u k l e t s a r e w e l l -a d a p t e d t o e a r l y l i f e , (9) p r e d a t i o n u p o n a u k l e t s i s l o w i n t h e S e v u o k u k c o l o n y , a n d (10) m o l t o f a d u l t s o v e r l a p s t h e b r e e d i n g e f f o r t i n A e t h i a s p p . b u t n o t i n C y c h l o r r h y n c h u s . E c o l o g i c a l a n d b e h a v i o r a l s p e c i a l i z a t i o n s i n t h e a n n u a l c y c l e s o f t h e s e a u k l e t s r e v e a l e d c l o s e s y n c h r o n i z a t i o n a n d s h o r t e n i n g o f b r e e d i n g e v e n t s n e c e s s a r y f o r b r e e d i n g i n t h e s h o r t A r c t i c s u m m e r . I t a p p e a r s t h a t t h e s e a u k l e t s a r e f a c e d w i t h t w o p r o b l e m s i n t i m i n g t h e i r b r e e d i n g c y c l e s . B r e e d i n g m u s t t a k e p l a c e w i t h i n a p e r i o d w h i c h i s l a r g e l y d i c t a t e d b y c l i m a t e a n d t h e y m u s t m a k e b e s t u s e o f t h e f o o d s u p p l y . i i i T A B L E OF CONTENTS P a g e A B S T R A C T i T A B L E OF CONTENTS i i i L I S T OF F I G U R E S v i L I S T OF T A B L E S X ACKNOWLEDGEMENTS x i i i I N T R O D U C T I O N • 1 A. S c o p e o f S t u d y a n d P r e v i o u s W o r k 1 B. S t u d y A r e a •••• • 4 C. M e t h o d s 1 6 D. D i s t r i b u t i o n o f N o r t h B e r i n g S e a A u k l e t s 2 1 E. M i g r a t i o n , D i s p e r s a l a n d W i n t e r D i s t r i b u t i o n o f N o r t h B e r i n g S e a A u k l e t s . 22 C H A P T E R I . T h e p r e - e g g S t a g e 26 A. A r r i v a l o f a u k l e t s a t t h e B r e e d i n g C o l o n y 26 B. E f f e c t o f Snow C o v e r o n t h e O n s e t o f N e s t i n g 2 8 C. C o l o n y S t r u c t u r e 35 a . P a i r - b o n d i n a u k l e t s 3 6 b . N e s t - s i t e t e n a c i t y 37 c . T e r r i t o r i a l i t y 3 9 d . N o n - b r e e d e r s 4 0 D. C o p u l a t i o n 4 0 i v C H A P T E R I I . T h e E g g S t a g e 4 4 A. T h e N e s t s o f P a r a k e e t , C r e s t e d a n d L e a s t A u k l e t s ... 4 4 a. D e s c r i p t i o n o f t h e n e s t i n g e n v i r o n m e n t 4 4 b . S e g r e g a t i o n o n t h e n e s t i n g s l o p e 4 8 B. E g g - l a y i n g i n A u k l e t s 5 9 a. T h e s e a s o n a l p a t t e r n o f e g g - l a y i n g 5 9 b . T h e d a i l y p a t t e r n o f e g g - l a y i n g 6 7 C. T h e C l u t c h i n P a r a k e e t , C r e s t e d a n d L e a s t A u k l e t s .. 6 8 a. D e s c r i p t i o n o f t h e e g g s 6 8 b . C l u t c h s i z e 75 c . R e p l a c e m e n t o f l o s t o r d e s t r o y e d e g g s 76 D. I n c u b a t i o n i n P a r a k e e t , C r e s t e d a n d L e a s t A u k l e t s .. 80 a. I n c u b a t i o n p e r i o d s i n a u k l e t s . 8 0 b . I n c u b a t i o n t e m p e r a t u r e s i n P a r a k e e t , C r e s t e d a n d L e a s t a u k l e t s 83 1. N e s t t e m p e r a t u r e s 83 2. B r o o d p a t c h e s a n d b r o o d p a t c h t e m p e r a t u r e s . 87 c . I n c u b a t i o n r h y t h m i n P a r a k e e t , C r e s t e d a n d L e a s t a u k l e t s 9 1 C H A P T E R I I I . T h e C h i c k S t a g e 94 A. T h e N e s t l i n g P e r i o d i n A u k l e t s 9 4 B. F e e d i n g H a b i t s o f A u k l e t s 97 a . P r e y s p e c i e s 9 7 C. G r o w t h o f C h i c k s 1 0 2 D. T h e r m o r e g u l a t i o n 1 2 2 V a . B o d y t e m p e r a t u r e s a n d t h e r m o r e g u l a t i o n i n a u k l e t c h i c k s 1 2 4 E. F l e d g i n g o f C h i c k s 1 3 6 C H A P T E R I V . P r e d a t i o n 1 4 4 C H A P T E R V. M o l t o f A d u l t s a n d J u v e n i l e s 1 5 2 C H A P T E R V I . T i m i n g o f t h e B r e e d i n g C y c l e s i n N o r t h B e r i n g S e a A u k l e t s • 1 5 7 A. U l t i m a t e F a c t o r s 1 5 8 a . N e s t i n g s i t e s 1 5 8 b . F o o d a n d i t s a v a i l a b i l i t y 1 6 2 B. P r o x i m a t e F a c t o r s 1 6 6 a . T e m p e r a t u r e . d u r i n g t h e p r e - e g g s t a g e 1 6 6 b . N e s t - s i t e s 1 6 7 c . D a y - l e n g t h a n d i n t e r n a l f a c t o r s 1 6 7 1. T h e t e s t i s c y c l e i n a d u l t m a l e a u k l e t s 1 6 8 C. A d d i t i o n a l A d a p t a t i o n s f o r T i m i n g i n A u k l e t s 1 7 1 D. S u m m a r y o f T i m i n g 1 7 5 SUMMARY 1 7 7 R E F E R E N C E S 1 8 2 A P P E N D I X I 1 9 3 L I S T OF F I G U R E S F i g u r e F a c i n g P a g e 1 O u t l i n e map o f S t . L a w r e n c e I s l a n d , A l a s k a , s h o w i n g l o c a t i o n s o f t h e S e v u o k u k a n d K o n g k o k a u k l e t c o l o n i e s , a n d t h e v i l l a g e o f G a m b e l l . 6 2 Map o f B e r i n g S e a a n d o t h e r w a t e r s i n h a b i t e d b y P a r a k e e t , C r e s t e d , a n d L e a s t a u k l e t s d u r i n g w i n t e r a n d b r e e d i n g s e a s o n s . 7 3 • Map o f S e v u o k u k M o u n t a i n a n d s u r r o u n d i n g w a t e r s . 8 4 P a t t e r n o f s n o w - m e l t o n S e v u o k u k M o u n t a i n i n 1 9 6 6 a n d 1 9 6 7 . 2 9 5 S n o w - c o v e r o n w e s t s l o p e o f S e v u o k u k M o u n t a i n , S t . L a w r e n c e I s l a n d , 2 J u n e 1 9 6 7 . 3 0 6 S e v u o k u k M o u n t a i n , n o r t h e a s t s l o p e , 23 J u n e 1 9 6 7 . 3 0 7 C r e s t e d a n d L e a s t a u k l e t s s e t t l e d o n r o c k s a n d s n o w o n t h e n o r t h e a s t s l o p e o f S e v u o k u k M o u n t a i n , 25 J u n e 1 9 6 7 . 32 8 A u k l e t s ( A e t h i a s p p . ) " s i t t i n g " o n t h e s n o w a t t h e b r o w o f t h e n o r t h e a s t s l o p e o f S e v u o k u k M o u n t a i n . 32 9 C r o s s ^ s e c t i o n o f m a i n n e s t t y p e s o f P a r a k e e t A u k l e t s o n S e v u o k u k M o u n t a i n , S t . L a w r e n c e I s l a n d . 4 9 1 0 C r o s s - s e c t i o n s o f m a i n n e s t t y p e s o f C r e s t e d A u k l e t s o n S e v u o k u k M o u n t a i n , S t . L a w r e n c e I s l a n d . 5 0 C r o s s - s e c t i o n s o f m a i n n e s t t y p e s o f L e a s t A u k l e t s o n S e v u o k u k M o u n t a i n , S t . L a w r e n c e I s l a n d . G e n e r a l i z e d m o d e l s h o w i n g t h e s e g r e g a t i o n b e t w e e n A e t h i a c r i s t a t e l l a a n d A. p u s i l l a o n t h e n e s t i n g s l o p e s a c c o r d i n g t o a v e r a g e r o c k d i a m e t e r . B r o m B e d a r d ( 1 9 6 7 : 1 2 3 ) . E g g - l a y i n g i n P a r a k e e t A u k l e t s o n S e v u o k u k M o u n t a i n , S t . L a w r e n c e I s l a n d . E g g - l a y i n g i n C r e s t e d A u k l e t s o n S e v u o k u k M o u n t a i n , S t . L a w r e n c e I s l a n d . E g g - l a y i n g i n L e a s t A u k l e t s o n S e v u o k u k M o u n t a i n , S t . L a w r e n c e I s l a n d . M e a n m a x i m u m a n d m i n i m u m a i r t e m p e r a t u r e s i n a n e s t - s i t e o f A. c r i s t a t e l l a d u r i n g t h e l a t t e r h a l f o f t h e b r e e d i n g s e a s o n , 1 9 6 6 . M e a n m a x i m u m a n d m i n i m u m a m b i e n t t e m p e r a t u r e s f o r t h e same p e r i o d a r e a l s o i n c l u d e d . R e l a t i v e i m p o r t a n c e ( i n v o l u m e ) o f v a r i o u s p r e y i t e m s o f v a r i o u s s i z e c a t e g o r i e s i n t h e e a r l y summer d i e t o f A e t h i a p u s i l l a a n d A. c r i s t a t e l l a ( f o o d i n g u l l e t s ) . F r o m B e d a r d ( 1 9 6 7 : 4 6 ) . R e l a t i v e i m p o r t a n c e ( i n v o l u m e ) o f v a r i o u s p r e y -t y p e s o f v a r i o u s s i z e c a t e g o r i e s i n t h e f o o d b r o u g h t t o t h e c h i c k d u r i n g A u g u s t a n d S e p t e m b e r ( f o o d i n n e c k - p o u c h e s ) . F r o m B e d a r d ( 1 9 6 7 : 4 7 ) . G r o w t h o f P a r a k e e t A u k l e t s . G r o w t h , o f C r e s t e d a n d L e a s t a u k l e t s . G r o w t h o f t h e o u t e r p r i m a r y i n P a r a k e e t , C r e s t e d a n d L e a s t a u k l e t s . G r o w t h i n L e a s t A u k l e t s i n r e l a t i o n t o t h e i r h a t c h i n g d a t e s i n 1 9 6 6 . G r o w t h c u r v e s o f A. p u s i l l a c h i c k (#169) h a t c h e d 2 9 J u l y 1 9 6 6 a n d A. p u s i l l a (#159) h a t c h e d 5 A u g u s t 1 9 6 6 . B o d y t e m p e r a t u r e s i n n e s t l i n g P a r a k e e t , C r e s t e d a n d L e a s t a u k l e t s a f t e r e x p o s u r e t o a m b i e n t t e m p e r a t u r e s a b o u t 1 1 ° C f o r 4 0 m i n u t e s . R e s p o n s e s o f P a r a k e e t A u k l e t o f a g e s 0 d a y t o 6 d a y s t o a m b i e n t t e m p e r a t u r e s . R e s p o n s e s o f C r e s t e d A u k l e t o f a g e s 0 d a y t o 3 d a y s t o a m b i e n t t e m p e r a t u r e s . R e s p o n s e s o f L e a s t A u k l e t o f a g e s 0 d a y t o 6 d a y s t o a m b i e n t t e m p e r a t u r e s . P a r a k e e t A u k l e t c h i c k , 29 d a y s o l d , 1 S e p t e m b e r 1 9 6 7 . S h o w i n g w o u n d o n i t s b a c k . L e a s t A u k l e t c h i c k , 2 8 d a y s o l d , 3 1 A u g u s t 1 9 6 7 . S h o w i n g m u t i l a t e d c o n d i t i o n o f l e f t e y e . I X 3 0 A g e n e r a l i z e d s u m m a r y o f b r e e d i n g a c t i v i t i e s a n d m o l t i n P a r a k e e t A u k l e t s . 1 5 3 3 1 A g e n e r a l i z e d s u m m a r y o f b r e e d i n g a c t i v i t i e s a n d m o l t i n C r e s t e d A u k l e t s . 1 5 4 3 2 A g e n e r a l i z e d s u m m a r y o f b r e e d i n g a c t i v i t i e s a n d m o l t i n L e a s t A u k l e t s . 1 5 5 3 3 N o r t h e a s t s l o p e o f S e v u o k u k M o u n t a i n s h o w i n g a c c u m u l a t i o n o f s n o w o n b r o w o f M o u n t a i n , 5 J u n e 1 9 6 7 . 1 6 1 34 C l o s e - u p v i e w o f b r o w o f n o r t h e a s t s l o p e o f S e v u o k u k M o u n t a i n s h o w i n g a c c u m u l a t i o n o f s n o w , 5 J u n e 1 9 6 7 . 1 6 1 35 S e a s o n a l c h a n g e i n t e s t i s s i z e ( w e i g h t o f l e f t t e s t i s ) o f L e a s t A u k l e t s i n 1 9 6 6 . 1 6 9 3 6 S e a s o n a l c h a n g e i n t e s t i s s i z e ( w e i g h t o f l e f t t e s t i s ) o f " s n o w - s i t t i n g " a n d " r o c k - s i t t i n g " L e a s t A u k l e t s i n 1 9 6 7 . 1 7 0 X L I S T OF T A B L E S T a b l e F a c i n g P a g e 1 A v e r a g e t e m p e r a t u r e s a t G a m b e l l , A l a s k a , f r o m 1 9 4 3 t h r o u g h t o 1 9 5 2 . 1 0 2 M o n t h l y a n d s e a s o n a l s n o w f a l l a t G a m b e l l , A l a s k a f r o m 1 9 4 2 - 1 9 4 3 t h r o u g h t o 1 9 5 2. 1 1 3 A i r t e m p e r a t u r e s r e c o r d e d a t 8m c o n t o u r a n d a t 120m c o n t o u r o n t h e n o r t h e a s t s l o p e o f S e v u o k u k M o u n t a i n , 1 9 6 6 . 13 4 A i r t e m p e r a t u r e s r e c o r d e d a t 8m c o n t o u r a n d a t 120m c o n t o u r o n t h e n o r t h e a s t s l o p e o f S e v u o k u k M o u n t a i n , 1 9 6 7 . 14 5 A r r i v a l d a t e s i n M a y o f a u k l e t s o n S t . L a w r e n c e I s l a n d d u r i n g 1 9 6 4 t o 1 9 6 7 s e a s o n s . 27 6 B a n d i n g a n d s u b s e q u e n t o b s e r v a t i o n s o f A. c r i s t a t e l l a a n d A. p u s i l l a i n 1 9 6 6 a n d 1 9 6 7 . 34 7 N e s t p e r i m a t e r s , p e r c h t o n e s t - s i t e d i s t a n c e s a n d t i m e i n v o l v e d f r o m l a n d i n g o n p e r c h t o e n t e r i n g n e s t - s i t e i n a u k l e t s . 5 6 8 E g g - l a y i n g i n P a r a k e e t , C r e s t e d a n d L e a s t a u k l e t s . 66 9 D i m e n s i o n s o f P a r a k e e t A u k l e t e g g s . 6 9 10 D i m e n s i o n s o f C r e s t e d a n d L e a s t a u k l e t e g g s . 70 1 1 W e i g h t s o f f r e s h a n d p i p p e d e g g s i n e i g h t s p e c i e s o f a l c i d s . 72 E g g - w e i g h t i n r e l a t i o n t o b o d y - w e i g h t i n s o m e a l c i d s . P e r i o d f r o m l a y i n g e g g u n t i l t h e c h i c k i s f r e e o t h e s h e l l i n C. p s i t t a c u l a , A. c r i s t a t e l l a a n d A p u s i l l a . T e m p e r a t u r e s i n s i d e t h e n e s t - s i t e o f A e t h i a  p s u i l l a . T e m p e r a t u r e s o f t h e f u l l y d e v e l o p e d b r o o d p a t c h c o m p a r e d t o t h e b o d y t e m p e r a t u r e s i n a u k l e t s . T e m p e r a t u r e s o f t h e f u l l y d e v e l o p e d b r o o d p a t c h c o m p a r e d t o b o d y t e m p e r a t u r e s i n some a l c i d s . N e s t l i n g p e r i o d s o f P a r a k e e t , C r e s t e d a n d L e a s t a u k l e t s . G r o w t h i n P a r a k e e t A u k l e t s , S t . L a w r e n c e I s l a n d , 1 9 6 7 . G r o w t h i n t h e C r e s t e d a n d L e a s t a u k l e t s , S t . L a w r e n c e I s l a n d . G r o w t h i n L e a s t A u k l e t s o n S t . L a w r e n c e I s l a n d , A l a s k a . B o d y w e i g h t s a n d m e a s u r e m e n t s o f y o u n g a u k l e t s a t h a t c h i n g a n d a t t i m e o f s e a - g o i n g . A v e r a g e d a i l y i n s t a n t a n e o u s g r o w t h r a t e s i n P a r a k e e t , C r e s t e d a n d L e a s t a u k l e t s . N e s t l i n g p e r i o d s o f L e a s t A u k l e t s i n r e l a t i o n t o t h e i r h a t c h i n g d a t e s , 1 9 6 6 . x i i 24 E s o p h a g e a l t e m p e r a t u r e s i n C y c h l o r r h y n c h u s  p s i t t a c u l a , A e t h i a c r i s t a t e l l a a n d A. p u s i l l a c h i c k s i n r e l a t i o n t o a g e a n d b u r r o w t e m p e r a t u r e . 1 2 5 25 E s o p h a g e a l t e m p e r a t u r e s o f C y c h l o r r h y n c h u s  p s i t t a c u l a , A e t h i a c r i s t a t e l l a a n d A. p u s i l l a d u r i n g t h e r m o r e g u l a t i o n e x p e r i m e n t s . 1 2 6 26 S u b c u t a n e o u s f a t d e p o s i t i o n i n k n o w n - a g e c h i c k s o f P a r a k e e t , C r e s t e d a n d L e a s t a u k l e t s f r o m h a t c h i n g t o s e a - g o i n g . 1 3 4 27 S u m m a r y o f r e l a t i v e c h i c k b o d y w e i g h t s a n d m e a s u r e m e n t s t o a d u l t b o d y w e i g h t s a n d m e a s u r e m e n t s i n a u k l e t s . 1 3 7 2 8 W e i g h t s a n d w i n g a r e a r a t i o s o f a u k l e t s . 1 3 9 2 9 S e a - g o i n g d a t e s o f P a r a k e e t , C r e s t e d a n d L e a s t a u k l e t s , S t . L a w r e n c e I s l a n d , 1 9 6 6 a n d 1 9 6 7 . 1 4 3 ACKNOWLEDGEMENTS I am g r a t e f u l t o Dr. M.D.F. Udvardy who supervised the i n i t i a l stages of t h i s work and provided f i n a n c i a l support from h i s N a t i o n a l Research C o u n c i l of Canada grant. I should l i k e to express my s i n c e r e a p p r e c i a t i o n to Dr. F.G. Cooch, Dean I. McT. Cowan, Dr. H.D. F i s h e r , Dr. W.S. Hoar, Dr. J.M. Taylor and Dr. M.D.F. Udvardy f o r t h e i r c o n s t r u c t i v e c r i t i c i s m of the t h e s i s . S p e c i a l thanks are extended to Dr. Jean Bedard who provided i n v a l u a b l e a s s i s t a n c e and advice at a l l stages of t h i s study. His constant encouragement during the planning stage, f i e l d - w o r k and w r i t i n g i s much appreciated. He gave f r e e access to unpublished data i n h i s f i l e s and c r i t i c a l l y read the manuscript. His u n s t i n t i n g help i s most g r a t e f u l l y acknowledged. While i n the f i e l d , I was helped on numerous occasions by the Eskimos of Gambell. I b e n e f i t e d from d i s c u s s i o n s , s c i e n t i f i c or otherwise, w i t h Mr. Steve Young. Dr. V.J. K r a j i n a and Dr. W. S c h o f i e l d k i n d l y i d e n t i f i e d forbs and mosses c o l l e c t e d on the n e s t i n g slopes. I b e n e f i t e d from a d i s c u s s i o n of growth w i t h Dr. H.C. Nordan. x i v Much help, advice, and encouragement were provided by M. A l e k s i u k , R.D. King, and K.W. Reid, and I wish to acknowledge t h e i r a s s i s t a n c e and th a t of a l l others who aided i n the p r e p a r a t i o n of t h i s t h e s i s . X V A d u l t P a r a k e e t A u k l e t s o n S e v u o k u k M o u n t a i n , S t . L a w r e n c e I s l a n d , A l a s k a . A d u l t C r e s t e d A u k l e t ( l e f t ) a n d a d u l t L e a s t A u k l e t ( r i g h t ) o n S e v u o k u k M o u n t a i n , S t . L a w r e n c e I s l a n d , A l a s k a . INTRODUCTION A. Scope of Study and Previous Work The m a j o r i t y of accu r a t e l y - t i m e d annual z o o l o g i c a l events are c l o s e l y connected w i t h r e p r o d u c t i o n . I f ad u l t i n d i v i d u a l s over a wide area mature simultaneously, an adequate supply of mates of both sexes i s l i k e l y to be ensured; and i f maturation i s f u r t h e r a s s o c i a t e d w i t h congregating or mixing of i n d i v i d u a l s from adjacent populations i t can be expected to produce a s u i t a b l e measure of outbreeding (Wynne-Edwards, 1962). As i n higher animals i n general, reproduction i n b i r d s i s i n t e r m i t t e n t . Some degree of i n t e r m i t t e n c y i s imposed by the temporal requirements of the re p r o d u c t i v e processes (Farner, 1967). More s i g n i f i c a n t , however, i n the e v o l u t i o n of i n t e r m i t t e n t r e p r o d u c t i v e f u n c t i o n i s the adaptive s i g n i f i c a n c e of c o n t r o l systems t h a t so r e g u l a t e reproduction t h a t young are produced duri n g the season i n which the p r o b a b i l i t y of s u r v i v a l tends to be maximal and s t r e s s on a d u l t s tends to be minimal (Aschoff, 1955; Farner, 1961, 1964; Immelmann, 1963; and o t h e r s ) . Among species t h a t i n h a b i t the d i s t i n c t l y annually p e r i o d i c environments of the mid and high l a t i t u d e s r e p r o d u c t i v e a c t i v i t y i s c h a r a c t e r i s t i c a l l y annual and the re p r o d u c t i v e seasons are c l e a r l y d e f i n e d (Aschoff, 1955; Farner, 1959, 1961, 2 1 9 6 4 ; L a c k , 1 9 5 0 ; a n d o t h e r s ) . I n d i s c u s s i n g t h e f a c t o r s t h a t c o n t r o l b r e e d i n g s e a s o n s i t i s h e l p f u l t o d i s t i n g u i s h b e t w e e n u l t i m a t e a n d p r o x i m a t e f a c t o r s , a s o r i g i n a l l y p o i n t e d o u t b y B a k e r ( 1 9 3 8 ) a n d r e s t a t e d b y Snow a n d S n o w ( 1 9 6 4 ) . U l t i m a t e f a c t o r s a r e t h o s e w h i c h m a k e b r e e d i n g p o s s i b l e , o r m o r e l i k e l y t o s u c c e e d , a t o n e t i m e o f t h e y e a r r a t h e r t h a n a n o t h e r , a n d i n c l u d e e s p e c i a l l y , f o r b i r d s , w e a t h e r a n d t h e f o o d s u p p l y f o r t h e y o u n g . T h e s e a r e t h e f a c t o r s t h a t u l t i m a t e l y d e t e r m i n e a t w h a t t i m e o f t h e y e a r b r e e d i n g t a k e s p l a c e . P r o x i m a t e f a c t o r s a r e t h o s e f a c t o r s i n t h e c h a n g i n g e n v i r o n m e n t t o w h i c h t h e o r g a n i s m r e s p o n d s , a n d w h i c h a c t a s t i m e r s o f b r e e d i n g i n t h e p h y s i o l o g i c a l s e n s e . T h e y n e e d b e t h e m s e l v e s o f n o d i r e c t s i g n i f i c a n c e f o r b r e e d i n g . T h e s h o r t e r t h e p e r i o d b e t w e e n t h e b e g i n n i n g o f b r e e d i n g a c t i v i t i e s a n d t h e p r o d u c t i o n o f y o u n g , t h e m o r e l i k e l y i t i s t h a t u l t i m a t e a n d p r o x i m a t e f a c t o r s w i l l b e c l o s e l y r e l a t e d . A f t e r s p e n d i n g s i x w e e k s i n t h e P e r r y R i v e r r e g i o n , N o r t h w e s t T e r r i t o r i e s , i n 1 9 6 5 , I b e c a m e m o r e a w a r e o f t h e s o m e t i m e s v e r y h a r s h c o n d i t i o n s f a c e d b y a n i m a l s w h i c h b r e e d i n t h e A r c t i c a n d r e a l i z e d h o w i m p o r t a n t i t i s f o r t h e m t o t i m e t h e i r b r e e d i n g e v e n t s p r e c i s e l y i f t h e i r s u r v i v a l i s t o b e e n s u r e d . I t w a s my i n t e n t i o n t o w o r k w i t h c o l o n i a l l y - n e s t i n g s e a - b i r d s i n a f a m i l y h a v i n g a d i v e r s e b r e e d i n g r a n g e w h i c h m i g h t g i v e s ome 3 i n s i g h t i n t o a d a p t a t i o n s f o r a r c t i c - b r e e d i n g s h o w n b y t h e s e b i r d s . When I l e a r n e d t h a t J e a n B e d a r d w a s c o m p l e t i n g a s t u d y o n e c o l o g i c a l s e g r e g a t i o n i n P a r a k e e t , C r e s t e d , a n d L e a s t a u k l e t s o n S t . L a w r e n c e I s l a n d , A l a s k a , a n d t h a t a p e r m a n e n t f i e l d c a m p h a d b e e n e s t a b l i s h e d t h e r e , I f o u n d a l l my r e q u i r e m e n t s s a t i s f i e d . T h e o c c u r r e n c e o f t h r e e c l o s e l y r e l a t e d a l c i d s p e c i e s p r o v i d e d e x c e l l e n t m a t e r i a l f o r c o m p a r a t i v e s t u d y w h i c h w o u l d s u p p l e m e n t r e c e n t s t u d i e s o f o t h e r P a c i f i c a l c i d s ( s e e D r e n t , 1 9 6 1 ; 1 9 6 5 ; P a y n e , 1 9 6 5 ; R i c h a r d s o n , 1 9 6 1 ; T h o r e s e n , 1 9 6 4 ; a n d o t h e r s ) . B e d a r d ' s a t t e n t i o n w a s d i r e c t e d p r i m a r i l y t o w a r d t h e s o c i a l s t r u c t u r e o f t h e s e s p e c i e s d u r i n g t h e p r e - e g g s t a g e , t h e i r f e e d i n g e c o l o g y a n d s e g r e g a t i o n o n t h e n e s t i n g s l o p e . O n l y s p o r a d i c a n d m i s c e l l a n e o u s o b s e r v a t i o n s o n t h e b r e e d i n g b i o l o g y o f t h e s e a u k l e t s h a d a p p e a r e d i n t h e l i t e r a t u r e p r i o r t o B e d a r d ' s w o r k . My p r o g r a m m e w a s , t h e r e f o r e , t o u n d e r t a k e a c o m p a r a t i v e s t u d y o f t h e b r e e d i n g e c o l o g y o f P a r a k e e t , C r e s t e d a n d L e a s t a u k l e t s e m p h a s i z i n g t h e o n s e t , d u r a t i o n a n d t e r m i n a t i o n o f t h e p r e - e g g , e g g - l a y i n g a n d i n c u b a t i o n , a n d c h i c k s t a g e s , a n d t o : (1) s t u d y t h e c l i m a t i c c o n d i t i o n s t h r o u g h o u t t h e b r e e d i n g s e a s o n a n d t h e i r e f f e c t s i f a n y o n t i m i n g i n a u k l e t s , a n d (2) e l u c i d a t e t h e a p p a r e n t a d a p t i v e s i g n i f i c a n c e o f t h e t i m i n g w h i c h e x i s t s . B e f o r e d e s c r i b i n g t h e s t u d y a r e a a n d m e t h o d s , a w o r d o n t h e s y s t e m a t i c p o s i t i o n o f t h e N o r t h P a c i f i c p l a n k t o n - f e e d i n g a u k l e t s i s n e c e s s a r y . 4 The systematic p o s i t i o n of the plankton-feeding a l c i d s has not been s t u d i e d i n d e t a i l . I t i s apparent from a p e r u s a l of the l i t e r a t u r e p e r t a i n i n g to the A l c i d a e that much confusion e x i s t e d during i t s e a r l y . c l a s s i f i c a t i o n (Coues, 1868; Shufeldt, 1891; and o t h e r s ) , and the s i t u a t i o n does not appear to be completely s e t t l e d today (see Gysels and Rabaey, 1964). In h i s monograph on the A l c i d a e , Coues (1868) l i s t s , up to 1868, no l e s s than f i v e d i f f e r e n t g eneric names a p p l i e d to the present-day Cychlorrhynchus. Using the type, by monotypy, A l c a p s i t t a c u l a P a l l a s (1769), Kaup described the present genus, Cychlorrhynchus Kaup (1829), w h i l e the o r i g i n a l s p e c i f i c name was r e t a i n e d (A.O.U. C h e c k - l i s t , 1957: 254). S i m i l a r confusion p r e v a i l e d during the i n i t i a l d e s c r i p t i o n of A e t h i a c r i s t a t e l l a and A. p u s i l l a . Using the type, again by monotypy, A l c a cr i s t a t e l l a P a l l a s (1769), Merrem described the present genus, A e t h i a Merrem (1788), w h i l e the o r i g i n a l s p e c i f i c name of the Crested Auklet has a l s o been r e t a i n e d . A. p u s i l l a ( P a llas) was o r i g i n a l l y d e scribed as U r i a p u s i l l a P a l l a s (1811). Thus, the names, Parakeet Auklet, Cychlorrhynchus  p s i t t a c u l a ( P a l l a s ) , Crested Auklet, A e t h i a c r i s t a t e l l a ( P a l l a s ) , and Least A u k l e t , A e t h i a p u s i l l a ( P a l l a s ) , w i l l be u t i l i z e d throughout t h i s t h e s i s . B. Study Area The f i e l d - w o r k was c a r r i e d out on St. Lawrence 5 I s l a n d ( f i g u r e 1) i n t h e n o r t h - c e n t r a l s e c t o r o f t h e B e r i n g S e a ( f i g u r e 2 ) ; t h e s t u d y i t s e l f w a s l i m i t e d t o t h e c o l o n y o n S e v u o k u k M o u n t a i n a n d w a t e r s s u r r o u n d i n g t h e N o r t h w e s t C a p e a r e a o f t h e I s l a n d ( f i g u r e 3 ) . T h e I s l a n d , a n a r c t i c l a n d m a s s o f a b o u t 2 , 0 0 0 s q u a r e m i l e s , l i e s a b o u t 2 0 0 m i l e s d i r e c t l y s o u t h o f t h e B e r i n g S t r a i t . T h e N o r t h w e s t C a p e i s a b o u t 4 0 m i l e s f r o m t h e n e a r e s t S i b e r i a n p o i n t , C h a p l i n o , a n d t h e N o r t h e a s t C a p e i s a b o u t 1 3 0 m i l e s f r o m t h e A l a s k a n S e w a r d P e n i n s u l a . T h e p h y s i o g r a p h y o f S t . L a w r e n c e I s l a n d h a s b e e n d e s c r i b e d b y F a y a n d C a d e ( 1 9 5 9 ) a n d s u p p l e m e n t e d b y T h o m p s o n ( 1 9 6 7 ) f o r N o r t h e a s t C a p e a n d t h e P u n u k I s l a n d s . T h e d e t a i l e d d e s c r i p t i o n o f t h e n e s t i n g s l o p e s i n t h e s t u d y a r e a o n S e v u o k u k M o u n t a i n w i l l b e p r e s e n t e d i n C h a p t e r I I . T h e c l i m a t i c c o n d i t i o n s o f t h e I s l a n d h a v e a n i m p o r t a n t i n f l u e n c e o n a u k l e t s ' b r e e d i n g a n d w i l l b e d e m o n s t r a t e d l a t e r i n t h i s t h e s i s ; h o w e v e r , i t i s n e c e s s a r y a t t h i s p o i n t t o s u m m a r i z e a v a i l a b l e c l i m a t i c d a t a . T h e I s l a n d h a s a t y p i c a l a r c t i c m a r i t i m e c l i m a t e e v e n t h o u g h i t i s a b o u t . 2 5 0 m i l e s s o u t h o f t h e A r c t i c C i r c l e . T h e f o l l o w i n g s u m m a r y f r o m t h e U n i t e d S t a t e s W e a t h e r -B u r e a u ( 1 9 5 3 ) d e p i c t s t h e w i n d y , s t o r m y a n d f o g g y n a t u r e o f G a m b e l l ' s c l i m a t e ( s u m m a r y o f d a t a c o l l e c t e d f r o m 1 9 4 3 t o 1 9 5 2 ) : . T e m p e r a t u r e s a t G a m b e l l a r e m o d e r a t e l y l o w , t h e m e a n y e a r l y t e m p e r a t u r e b e i n g 2 4 . 2 ° F . E x t r e m e l o w t e m p e r a t u r e s a r e r a r e , d u e i n p a r t t o h i g h s u r f a c e w i n d s , h i g h f r e q u e n c y o c c u r r e n c e O u t l i n e map o f S t . L a w r e n c e I s l a n d , A l a s k a , s h o w i n g l o c a t i o n s o f t h e S e v u o k u k a n d K o n g k o k a u k l e t c o l o n i e s , a n d t h e v i l l a g e o f G a m b e l l . Legend f o r F i g u r e 2 Map o f t h e B e r i n g Sea and o t h e r w a t e r s i n h a b i t e d by P a r a k e e t , C r e s t e d and L e a s t a u k l e t s d u r i n g w i n t e r and b r e e d i n g seasons. 176 ° 8 Legend f o r F i g u r e 3 Map o f Sevuokuk Mountain and s u r r o u n d i n g w a t e r s . S o l i d arrow i n d i c a t e s n o r t h e a s t s l o p e where n e s t i n g s t u d i e s were conducted; open arrow i n d i c a t e s l o c a t i o n where b i r d s were c o l l e c t e d on west s l o p e . Contour l e v e l s a r e i n f e e t . I n s e t shows Sevuokuk Mountain i n r e l a t i o n t o t h e remainder o f t h e I s l a n d . o f low c l o u d , h i g h average sky c o v e r and p r o x i m i t y t o t h e B e r i n g Sea. The r e c o r d low t e m p e r a t u r e o f -30 o c c u r r e d i n F e b r u a r y 1947. The a l l t i m e h i g h i s 65 e s t a b l i s h e d i n J u l y o f 1952. Mean y e a r l y p r e c i p i t a t i o n i s f a i r l y e v e n l y d i s t r i b u t e d t o a l l months. P r e c i p i t a t i o n o c c u r s on a p p r o x i m a t e l y 300 days o f each y e a r . T o t a l s n o w f a l l i s n o t r e p r e s e n t a t i v e o f d e p t h o f snow on ground as t h e g r e a t e r p a r t o f s n o w f a l l i s blown from t h e ground as p r e v a i l i n g winds a r e from seaward, NE, v e r y l i t t l e o f t h e d i s p l a c e d snow i s r e p l a c e d . Mean average wind v e o l c i t i e s a r e h i g h and storms w i t h s t r o n g w i n d s may be e x p e c t e d i n each month. The a l l t i m e h i g h v e l o c i t y r e c o r d e d a t t h i s s t a t i o n i s 100 mph from t h e s o u t h , w h i c h o c c u r r e d i n O c t o b e r , 1946. Average sky c o v e r , s u n r i s e t o s u n s e t , i s h i g h w i t h a p p r o x i m a t e l y 32 days per y e a r w i t h c l e a r sky. T a b l e 1 shows t h e average t e m p e r a t u r e and t a b l e 2 p r e s e n t s s n o w f a l l a t Gambell from 1943 t o 1952 (data f r om U.S. Weather Bureau, 1953). The c l i m a t e d u r i n g t h e a u k l e t s ' b r e e d i n g season, about 20 May t o 10 September, i s c h a r a c t e r i z e d by p r e v a i l i n g winds from t h e s o u t h and southwest o f t e n accompanied by f o g and r a i n . From A p r i l t o November th e I s l a n d ' s weather i s a f f e c t e d by t h e n o r t h e r n edge o f a major low p r e s s u r e system, c e n t e r e d i n t h e A l e u t i a n I s l a n d s (U.S. Navy, 1956). A p r i m a r y t r a c k o f s t o r m centers., o r i g i n a t i n g i n t h e N o r t h P a c i f i c Ocean and s o u t h e r n B e r i n g Sea, p a s s e s over or near t h e I s l a n d d u r i n g J u l y and August r e s u l t i n g i n h i g h winds and i n t e r m i t t e n t r a i n s w h i c h a r e b e l i e v e d by Fay and Cade (1959:77) "to be prominent f a c t o r s a f f e c t i n g b r o o d s u r v i v a l o f many o f t h e b r e e d i n g b i r d s , " a p o i n t w h i c h 10 L e g e n d f o r T a b l e 1 A v e r a g e t e m p e r a t u r e s a t G a m b e l l , A l a s k a , f r o m 1 9 4 3 t h r o u g h t o 1 9 5 2 . D a t a f r o m U n i t e d S t a t e s W e a t h e r B u r e a u ( 1 9 5 3 ) . T e m p e r a t u r e s c o n v e r t e d t o ° C . T A B L E 1 Y e a r J a n . F e b . M a r . A p r . M a y J u n e J u l y A u g . S e p t . O c t . N o v . D e c . A n n u a ! 1 9 4 3 - 1 5 . 6 - 1 7 . 4 - 1 1 . 3 - 8 . 0 0.4 4. 3 7.8 7.4 3.8 0.9 - 2 . 3 - 1 3 . 4 - 3 . 6 1 9 4 4 - 1 9 . 1 - 1 4 . 7 - 1 5 . 1 - 1 1 . 4 - 1 . 7 2.8 6.4 6. 7 4.5 - 0 . 4 - 7 . 8 - 1 2 . 2 1 - 5 . 6 1 9 4 5 - 1 5 . 2 - 1 8 . 1 - 2 0 . 2 - 6 . 2 - 2 . 6 2.3 8. 7 7.0 5.2 - 2 . 3 - 7 . 7 - 1 4 . 0 - 5 . 3 1 9 4 6 - 1 4 . 6 - 2 1 . 5 - 1 8 . 6 - 1 2 . 4 - 2 . 3 3.0 6.4 5.7 3.8 0.2 - 4 . 3 - 1 3 . 8 - 5 . 7 1 9 4 7 - 1 7 . 6 - 1 3 . 3 - 1 6 . 8 - 7 . 7 - 0 . 4 2.6 6. 3 6.5 3.1 - 1 . 5 - 7 . 1 - 1 6 . 5 - 5 . 2 1 9 4 8 - 1 8 . 3 - 1 4 . 0 - 1 3 . 0 - 2 . 3 - 1 . 8 4.3 6.5 6.3 3.5 - 1 . 8 - 7 . 3 - 1 1 . 2 - 4 . 1 1 9 4 9 - 1 2 . 7 - 1 4 . 6 - 1 0 . 6 - 1 0 . 2 - 3 . 1 1.5 6.1 8.1 4. 7 1.3 - 4 . 1 - 9 . 5 - 3 . 6 1 9 5 0 - 5 . 0 - 1 1 . 7 - 1 1 . 6 - 8 . 1 - 2 . 8 2.6 7.0 8.0 4. 7 1.6 - 6 . 1 - 6 . 8 - 2 . 2 1 9 5 1 - 1 7 . 5 - 1 7 . 7 - 1 5 . 8 - 8 . 3 - 1 . 0 3.3 6.8 6.9 3.3 0.3 - 3 . 3 - 7 . 2 - 4 . 2 1 9 5 2 - 1 3 . 3 - 1 7 . 8 - 1 5 . 3 - 9 . 3 - 2 . 2 2. 1 5.8 6.9 4. 9 0.8 - 2 . 1 - 1 2 . 0 - 4 . 3 1 1 L e g e n d f o r T a b l e 2 M o n t h l y a n d s e a s o n a l s n o w f a l l a t G a m b e l l , A l a s k a , f r o m 1 9 4 2 - 4 3 t h r o u g h t o 1 9 5 2 . D a t a f r o m U n i t e d S t a t e s W e a t h e r B u r e a u ( 1 9 5 3 ) . D e p t h o f s n o w f a l l c o n v e r t e d t o cm. TABLE 2 Season Ju l y Aug. Sept. Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June T o t a l 1942-43 „, 6.0 15.5 17. 6 10. 3 7.8 0. 0 1943-44 0. 0 0. 0 24.0 .16.7 13. 3 14.5 43.5 11. 3 20. 6 4. 8 T 148. 8 1944-45 0.0 T T 5.3 13.0 33. 3 22. 8 33. 8 6.5 7.8 3.0 2.0 127. 3 1945-46 0. 0 0.0 T 37.8 24.0 9.0 16. 3 5.3 4.3 21.5 6. 0 T 124. 0 1946-47 T T T 15. 3 7.3 15.0 12.0 16.5 1.5 2.5 6.0 0.0 76.0 1947-48 0.0 T 0.3 18. 8 9.5 29. 0 16. 3 12.5 43.5 3.3 0. 25 T 133. 3 1948-49 0.0 0.0 T 3.3 13.5 16. 3 13.5 11. 3 17.5 8. 3 16. 0 5.0 100. 0 1949-50 0. 0 T T 18. 0 45. 3 44. 0 80. 3 14. 8 121.3 137. 8 14. 3 T 475.5 1950-51 0.0 0.0 T 4.5 27.0 78. 3 10.5 121.5 42. 8 49. 0 24.5 3.3 358. 0 1951-52 0.0 0.0 5.0 30.0 45.5 22.5 38. 0 27.5 27.5 22. 3 15.5 3.3 235. 0 1952 0.0 0. 0 0. 0 7.8 67.5 82.5 _ _ — — — — — *Trace • 12 w i l l b e m e n t i o n e d l a t e r i n t h i s t h e s i s . T a b l e s 3 a n d 4 s h o w w e e k l y m e a n t e m p e r a t u r e s a t t h e b a s e o f S e v u o k u k M o u n t a i n (8m o r 2 5 f t c o n t o u r ) a n d o n t h e r i m o f t h a t m o u n t a i n (120m o r 3 6 0 f t c o n t o u r ) f r o m 15 J u l y t o 13 S e p t e m b e r 1 9 6 6 a n d 6 J u n e t o 7 S e p t e m b e r 1 9 6 7 . T h e o c c u r r e n c e o f n o r t h e a s t g a l e f o r c e w i n d s o f 35 t o 4 5 m.p.h. d u r i n g t h e p e r i o d s 2 8 A u g u s t t o 2 S e p t e m b e r , 7 t o 1 0 S e p t e m b e r 1 9 6 6 , a n d 1 9 t o 23 A u g u s t , 2 8 A u g u s t t o 2 S e p t e m b e r 1 9 6 7 a d v e r s e l y a f f e c t e d m a n y c h i c k s ' d e p a r t u r e f o r s e a ( s e e C h a p t e r I I I ) . T h e m a r i n e e n v i r o n m e n t i n h a b i t e d b y t h e a u k l e t s d u r i n g t h e g r e a t e r p a r t o f t h e i r l i f e c y c l e s h a s b e e n d e s c r i b e d b y B e d a r d ( 1 9 6 7 : 2 9 - 3 3 ) . T h e a v i f a u n a o f S t . L a w r e n c e I s l a n d h a s b e e n s t u d i e d b y F r i e d m a n n ( 1 9 3 2 ) , F a y a n d C a d e ( 1 9 5 9 ) , a n d s u p p l e m e n t e d b y S a u e r a n d U r b a n ( 1 9 6 4 ) , T h o m p s o n ( 1 9 6 7 ) a n d S e a l y , F a y a n d B e d a r d ( m a n u s c r i p t i n p r e p a r a t i o n ) . F a y a n d C a d e ( 1 9 5 9 ) d i v i d e d t h e p h y s i c a l a n d v e g e t a t i o n a l f e a t u r e s o f t h e I s l a n d i n t o t e n a v i a n h a b i t a t s ; t h e s e a - c l i f f h a b i t a t , o f w h i c h S e v u o k u k M o u n t a i n i s a p a r _ t , r e p r e s e n t s t h e t y p e o f n e s t i n g h a b i t a t m o s t , d e n s e l y i n h a b i t e d b y b i r d s o n t h i s I s l a n d . B e d a r d ( p e r s o n a l c o r r e s p o n d e n c e ) e s t i m a t e d t h e t o t a l a u k l e t p o p u l a t i o n o n S e v u o k u k M o u n t a i n t o c o n s i s t o f a b o u t 1 8 3 , 0 0 0 A e t h i a s p p . a n d a b o u t 2 , 0 0 0 C y c h l o r r h y n c h u s . O t h e r a v i a n s p e c i e s 13 Legend f o r T a b l e 3 A i r t e m p e r a t u r e s r e c o r d e d a t 8m c o n t o u r and a t 120m c o n t o u r on t h e n o r t h e a s t s l o p e o f Sevuokuk Mountain, 1966. Temperatures measured i n °C. T A B L E 3 M e a n M e a n P e r i o d M a x i m u m M i n i m u m x T e m p e r a t u r e 8 m C o n t o u r J u l y 1 5 - 2 1 1 2 . 0 7.0 9.6 2 2 - 2 8 1 3 . 5 8. 2 1 0 . 9 2 9 - 3 1 1 3 . 3 8. 0 1 0 . 6 A u g u s t 1-7 1 2 . 4 9. 2 1 0 . 8 8-14 1 2 . 4 8.5 1 0 . 5 1 5 - 2 1 1 0 . 5 7.0 8.7 2 2 - 2 8 1 1 . 5 8.0 9.5 2 9 - 3 1 8.0 6.0 7.0 S e p t e m b e r 1-7 9. 2 6. 1 6. 2 8-13 9.3 7.5 8.3 1 2 0 m C o n t o u r J u l y 1 5 - 2 1 1 3 . 8 7.8 1 0 . 0 2 2 - 2 8 1 3 . 0 7.2 1 0 . 8 2 9 - 3 1 1 6 . 0 8. 6 1 2 . 3 A u g u s t 1-7 1 3 . 4 9. 2 1 1 . 0 8-14 1 2 . 1 9.1 1 0 . 7 1 5 - 2 1 1 0 . 2 6. 7 6.5 2 2 - 2 8 1 0 . 6 8.6 9.6 2 9 - 3 1 7.6 5.6 6. 7 S e p t e m b e r 1-7 9.4 5.7 7.5 8 - 1 3 8.5 6.0 7.2 14 L e g e n d f o r T a b l e 4 A i r t e m p e r a t u r e s r e c o r d e d a t 8m c o n t o u r a n d a t 120m c o n t o u r o n t h e n o r t h e a s t s l o p e o f S e v u o k u k M o u n t a i n , 1 9 6 7 . T e m p e r a t u r e s m e a s u r e d i n ° C . TABLE 4 P e r i o d Mean Maximum Mean Min imum x Temperature 8 m Contour June J u l y August September 6-7 8-14 15-21 22-28 29-30 1-7 8-14 15-21 22-28 29-31 1-7 8-14 15-21 22-28 29-31 1-7 7. 1 7.8 8. 2 9.3 9.1 12.8 14. 8 12.8 10.3 11. 2 9. 10. 13. 11. 10. 6 5 4 2 1 4. 2 4.5 6. 6. 6. 8. 9. 9. 8. 3 10. 2 8. 6. 8. 7. 7. 5 0 6 6 2 5.6 6.1 7.9 7.5 7.4 10.6 12.3 11.6 9.3 10.7 9.1 8.3 11.0 9.4 8.7 120 m Contour June J u l y August September 6-7 7.0 4.0 5.5 8-14 14. 7 6. 3 10.5 15-21 15. 3 7.6 11.5 22-28 21.5 8. 7 15. 1 29-30 14.5 9. 0 11. 8 1-7 20. 1 10. 0 15.0 8-14 17. 2 11. 0 14. 1 15-21 16. 7 11.5 14. 1 22-28 18. 8 12. 0 15.4 29-31 14. 0 12. 3 13. 2 1-7 16.8 12. 6 14. 7 8-14 14. 7 11.5 13.1 15-21 13. 8 10. 7 12. 3 22-28 17.5 12. 7 15.5 29-31 14. 6 11. 3 12. 9 1-7 12.0 11. 2 11.6 w h i c h b r e d o n t h e r o c k - p i l e c l i f f s o f t h i s m o u n t a i n d u r i n g t h e s t u d y , i n a p p r o x i m a t e o r d e r o f d e c r e a s i n g a b u n d a n c e , w e r e : P i g e o n G u i l l e m o t ( C e p p h u s c o l u m b a ) H o r n e d P u f f i n ( F r a t e r c u l a c o r n i c u l a t a ) S n ow B u n t i n g ( P l e c t r o p h a n a x n i v a l i s ) T u f t e d P u f f i n ( L u n d a c i r r h a t a ) W h i t e W a g t a i l ( M o t a c i l l a a l b a ) R a v e n ( C o r v u s c o r a x ) A n a c c o u n t o f t h e t e r r e s t i a l m a m m als o f S t . L a w r e n c e I s l a n d h a s b e e n g i v e n b y R a u s c h ( 1 9 5 7 ) . T u n d r a s h r e w s ( S o r e x t u n d r e n s i s ) , a r c t i c g r o u n d s q u i r r e l s ( C i t e l l u s u n d u l a t u s ) , r e d - b a c k e d v o l e s ( C l e t h r i o n o m y s  r u t i l u s ) a n d t u n d r a v o l e s ( M i c r o t u s o e c o n o m u s ) l i v e i n j u x t a p o s t i i o n t o t h e n e s t i n g a u k l e t s o n S e v u o k u k M o u n t a i n . A r c t i c f o x e s ( A l o p e x l a g o p u s ) , f a i r l y common r e s i d e n t s i n t h e K o n g k o k c o l o n y ( B e d a r d , p e r s o n a l c o m m u n i c a t i o n ) , w e r e o b s e r v e d f o u r t i m e s i n t h e S e v u o k u k c o l o n y d u r i n g t h e s t u d y . S l e d g e d o g s ( C a n i s f a m i l i a r i s ) f r e q u e n t l y h u n t e d i n t h e c o l o n y a n d i n 1 9 6 7 t h r e e l i v e d i n t h e S e v u o k u k c o l o n y d u r i n g t h e e n t i r e s u m m e r . T h e v e g e t a t i o n o f S t . L a w r e n c e I s l a n d , i n g e n e r a l t e r m s , i s c h a r a c t e r i s t i c o f t h e c i r c u m p o l a r t u n d r a b i o m e . F a y a n d C a d e ( 1 9 5 9 ) h a v e s u m m a r i z e d t h e s p a r s e l i t e r a t u r e o n t h e f l o r a o f t h i s I s l a n d a n d a n e c o l o g i c a l s t u d y o f i t s v e g e t a t i o n i s p r e s e n t l y u n d e r w a y ( S . Y o u n g , p e r s o n a l c o m m u n i c a t i o n ) . T h e m o s t p r e d o m i n a n t f o r m o f v e g e t a t i o n o n t h e n e s t i n g s l o p e w a s a l o w g r o u n d c o v e r 16 c o m p o s e d o f m o s s e s a n d l i c h e n s ; t h e m o s t common g e n e r a o f m o s s e s w e r e C e r a t o d o n , B r y u m , C a m p h y l i u m , D r e p a n o c l a d u s a n d P o g o n a t u m w h i c h g r e w o n a n d a m o n g t h e r o c k s f r o m a b o u t t h e 30m c o n t o u r t o t h e b r o w . L i c h e n s w e r e r e p r e s e n t e d b y C l a d o n i a , C e r t r a r i a a n d A l e c t o r i a . S h r u b b y s p e c i e s e n c o u n t e r e d w e r e R u b u s c h a m a e m o r u s a r i d S a l i x s p p . a n d t h e m o s t common f o r b s w e r e Sedum, P e d i c u l a r i s a n d S a x i f r a g a p l u s s e v e r a l g e n e r a o f s e d g e s . C. M e t h o d s I n 1 9 6 6 f i e l d - w o r k c o m m e n c e d 13 M a y a n d e n d e d o n 14 S e p t e m b e r ; i n 1 9 6 7 i t b e g a n o n 25 M a y a n d e n d e d o n 9 S e p t e m b e r . N e a r l y t h e e n t i r e p e r i o d w a s s p e n t i n t h e N o r t h w e s t C a p e a r e a o f t h e I s l a n d , t h a t i s , o n S e v u o k u k M o u n t a i n a n d , i n 1 9 6 6 , o f f s h o r e o n t h e B e r i n g S e a . O b s e r v a t i o n s w e r e made o n 12 J u n e 1 9 6 7 i n t h e K o n g k o k c o l o n y o n t h e s o u t h w e s t s i d e o f t h e I s l a n d ( f i g u r e 1) . P e r m a n e n t h e a d q u a r t e r s w e r e e s t a b l i s h e d i n G a m b e l l ; t e m p o r a r y c a mp w a s s e t u p o n t h e n o r t h e a s t s l o p e o f S e v u o k u k M o u n t a i n a t T a t e g n a k P o i n t ( f i g u r e 3) w h e r e o b s e r v a t i o n s a n d n e s t i n g s t u d i e s w e r e c o n d u c t e d . T h e d i s a p p e a r a n c e o f s n o w a n d c o n s e q u e n t e x p o s u r e o f n e s t i n g s i t e s w a s q u a n t i t a t i v e l y s t u d i e d o n t h e w e s t s l o p e o f S e v u o k u k M o u n t a i n b y m e a s u r i n g t h e r a t i o o f b a r e g r o u n d t o s n o w - c o v e r e d g r o u n d i n e a c h o f f i v e 17 p l o t s o n t h e w e s t s l o p e a n d t h r e e o n t h e n o r t h e a s t s l o p e , 14.2m t o a s i d e , a t d i f f e r e n t e l e v a t i o n s o n t h e s l o p e . T h e p l o t s w e r e r a n d o m l y s e l e c t e d i n a u k l e t n e s t i n g h a b i t a t . T h e d i m e n s i o n o f 14.2m t o a s i d e w a s s e l e c t e d b e c a u s e i t g a v e a n a r e a a p p r o x i m a t e l y 2 0 0 s q . m, a s u i t a b l e a r e a c o n s i d e r i n g t h a t t h e a u k l e t s ' n e s t i n g h a b i t a t i n t h e t a l u s s l o p e i s u s u a l l y i n t h e f o r m o f r o c k " s t r i p e s . " B i r d s " s i t t i n g " o n a s p c i f i c a r e a o f t h e s n o w w e r e l i v e - s t r a p p e d u s i n g " n o o s e c a r p e t s " ( s e e B e r g e r a n d H a m m e r s t r o m , 1 9 6 2 ) a n d w e r e b a n d e d a n d c o l o r - m a r k e d , u s i n g c o l o r c o m b i n a t i o n s o n e a c h l e g . S a m p l e s o f e a c h a u k l e t s p e c i e s w e r e c o l l e c t e d a t a p p r o x i m a t e l y w e e k l y i n t e r v a l s d u r i n g b o t h s e a s o n s . S a m p l e s o f e a c h a u k l e t s p e c i e s w e r e c o l l e c t e d a t s e a w i t h J e a n B e d a r d u s u a l l y b e t w e e n 1 3 0 0 a n d 1 7 0 0 h r ( a l l t i m e s i n t h i s t h e s i s a r e B e r i n g S e a T i m e ) d u r i n g t h e p r e - e g g , e g g - l a y i n g a n d i n c u b a t i o n s t a g e s . D u r i n g t h e c h i c k - r e a r i n g a n d s e a - g o i n g s t a g e s s a m p l e s w e r e t a k e n o n S e v u o k u k M o u n t a i n . T h e s t o r m y n a t u r e o f t h e B e r i n g S e a c l i m a t e l a r g e l y d i c t a t e d t h e i n t e r v a l s b e t w e e n s u c c e s s i v e c o l l e c t i n g t r i p s a t s e a . . . T h e l a c k o f w a t e r t r a n s p o r t a t i o n i n - 1 9 6 7 n e c e s s i t a t e d s a m p l i n g f r o m t h e w e s t s l o p e o f S e v u o k u k M o u n t a i n . A t o t a l o f 4 5 p s i t t a c u l a (3 9 m a l e s , 6 f e m a l e s ) w a s c o l l e c t e d i n 1 9 6 6 a n d a t o t a l o f 14 (7 m a l e s , 7 f e m a l e s ) i n 1 9 6 7 . A t o t a l o f 2 1 2 c r i s t a t e l l a ( 8 8 m a l e s , 1 0 4 f e m a l e s ) w a s c o l l e c t e d i n 1 9 6 6 a n d a t o t a l o f 92 (53 m a l e s , 3 9 f e m a l e s ) i n 1 9 6 7 . A t o t a l o f 2 2 3 p u s i l l a ( 1 2 5 m a l e s , 98 f e m a l e s ) w a s c o l l e c t e d i n 1 9 6 6 a n d a t o t a l o f 1 7 5 ( 1 0 1 m a l e s , 74 f e m a l e s ) i n 1 9 6 7 . E a c h b i r d w a s w e i g h e d t o t h e n e a r e s t O . l g u s i n g a s p r i n g b a l a n c e . G o n a d s w e r e d i s s e c t e d ; t h e l e n g t h a n d g r e a t e s t w i d t h o f e a c h t e s t i s o r t h e d i a m e t e r o f t h e l a r g e s t f o l l i c l e w e r e m e a s u r e d t o t h e n e a r e s t 0.1mm w i t h K a n o n c a l i p e r s , f i x e d i n B o u i n ' s p i c r o - f o r m o l - a c e t i c s o l u t i o n f o r 24 h o u r s , a n d t h e n p r e s e r v e d i n 7 0 % e t h y l a l c o h o l . T h e l e f t t e s t e s w e r e s u b s e q u e n t l y w e i g h e d t o t h e n e a r e s t O . O l g o n a M e t i e r a n a l y t i c a l b a l a n c e . S u b c u t a n e o u s f a t o n e a c h b i r d w a s q u a n t i t a t i v e l y e s t i m a t e d u s i n g a s c a l e o f 0 t o 4; 0 r e p r e s e n t s n o s u b c u t a n e o u s f a t a n d 4 r e f e r s t o h e a v y f a t d e p o t s . T h e p r e s e n c e a n d c o n d i t i o n o f b r o o d p a t c h e s w e r e n o t e d a s w e l l a s b o d y m o l t a n d m o l t o f t h e r e m i g e s . E g g - l a y i n g d a t e s o f e a c h s p e c i e s w e r e d e t e r m i n e d b y d i s s e c t i o n o f a d u l t f e m a l e s a n d b y s e a r c h i n g f o r " p o t e n t i a l " n e s t - s i t e s a m o n g t h e r o c k i n t e r s t i c e s a n d t h e n r e v i s i t i n g t h e m u n t i l t h e s i n g l e " e g g a p p e a r e d . T h e l a t t e r m e t h o d w a s s u c c e s s f u l p r o v i d e d t h a t t h e n e s t - s i t e w a s s u i t a b l e , a c o n d i t i o n r e n d e r e d p o s s i b l e t o a s s e s s o n l y t h r o u g h e x p e r i e n c e a n d f a m i l i a r i t y w i t h a n a u k l e t ' s n e s t . A p o w e r f u l f l a s h l i g h t p r o v e d e s s e n t i a l i n the search f o r nests. Scratch marks on the c r e v i c e f l o o r o f t e n i n d i c a t e d an a u k l e t ' s egg would appear. In 1967 the o b t a i n i n g of egg-laying dates was s i m p l i f i e d by having a number of known n e s t - s i t e s from 1966. Each n e s t - s i t e was numbered on a west-facing boulder (sheltered from the northeast p r e v a i l i n g wind and r a i n ) using commercial red spray p a i n t . Lengths and widths of 18 p s i t t a c u l a , 65 c r i s t a t e l l a and 126 p u s i l l a eggs were measured to the nearest 0.1mm. Each egg was numbered w i t h the corresponding nest number. Nest entrance perimeters were measured, by p l a c i n g a length of s t r i n g around the entrance and subsequently determining the d i s t a n c e on a measuring tape. The d i s t a n c e from the perch to the nest entrance was measured w i t h a meter cha i n . Environmental temperatures were recorded to the nearest 1.0°c using Bacharach continuous r e c o r d i n g thermometers. A thermometer was placed at the 8m or 25ft contour on the northeast slope of Sevuokuk Mountain and a second thermometer was placed at the 120 m or 360ft contour near the r i m of the mountain. Two -thermometers w i t h extension leads recorded the temperature i n a c r i s t a t e l l a n e s t - s i t e and a p u s i l l a n e s t - s i t e . Wind v e l o c i t y was measured using a " F l o r i t e " wind gauge. Body temperatures were measured by means of a p o r t a b l e , 20 b a t t e r y - p o w e r e d , m u l t i - c h a n n e l t h e r m i s t e r t h e r m o m e t e r m a n u f a c t u r e d b y t h e Y e l l o w S p r i n g s I n s t r u m e n t C o m p a n y , Y e l l o w S p r i n g s , O h i o . A l l t h e r m i s t e r s w e r e c a l i b r a t e d w i t h a B u r e a u o f S t a n d a r d s t h e r m o m e t e r ; t e m p e r a t u r e s w e r e m e a s u r e d b y g e n t l y i n s e r t i n g a v i n y l - s h e a t h e d t h e r m i s t e r p r o b e d o w n t h e e s o p h a g u s t o t h e s t o m a c h , a n d r e a d a f t e r 1 2 0 s e c o n d s ( t e s t i n g s h o w e d t h a t b y t h i s t i m e " n o r m a l " t e m p e r a t u r e s w e r e r e g i s t e r e d ) . C h i c k s w e r e r e m o v e d f r o m t h e i r n e s t - s i t e a n d m e a s u r e m e n t s w e r e t a k e n w i t h i n 30 s e c o n d s . A s F a r n e r a n d S e r v e n t y ( 1 9 5 9 ) p o i n t e d o u t , t h i s t y p e o f t e m p e r a t u r e m e a s u r e m e n t a d m i t t e d l y i n v o l v e s b i a s ( U d v a r d y , 1 9 5 3 ) w h i c h c o u l d b e e l i m i n a t e d u s i n g p e r m a n e n t l y i n s t a l l e d t h e r m o c o u p l e s ( B a r t h o l o m e w a n d D a w s o n , 1 9 5 4 ) ; h o w e v e r , s u c h a p r o c e d u r e w a s n o t f e a s i b l e h e r e d u e t o t h e h i g h l o s s o f c h i c k s . B u r r o w t e m p e r a t u r e s w e r e m e a s u r e d s i m u l t a n e o u s l y w i t h t h e c h i c k b o d y t e m p e r a t u r e s b y p l a c i n g a v i n y l - s h e a t h e d t h e r m i s t e r p r o b e i n t o t h e b u r r o w a f t e r t h e c h i c k w a s r e m o v e d . E g g t e m p e r a t u r e s w e r e o b t a i n e d b y s l i p p i n g a v i n y l - s h e a t h e d p r o b e 3mm i n d i a m e t e r t h r o u g h . a s m a l l h o l e d r i l l e d t h r o u g h t h e s h e l l . P i p p e d e g g t e m p e r a t u r e s w e r e o b t a i n e d b y g e n t l y i n s e r t i n g t h i s p r o b e t h r o u g h t h e p i p h o l e a n d p l a c i n g t h e p r o b e a g a i n s t t h e e m b r y o . S t a n d a r d a l u m i n u m b a n d s i s s u e d b y t h e U n i t e d S t a t e s F i s h a n d W i l d l i f e S e r v i c e w e r e a p p l i e d t o e a c h n e s t l i n g s t u d i e d , n o . 4 f o r p s i t t a c u l a a n d c r i s t a t e l l a and no. 2 f o r p u s i l l a , at four to f i v e days of age f o r the former two species and at about three days of age f o r the l a t t e r . Each chick was weighed each day between 1000 and 1400 hr using a s p r i n g balance, accurate t o the nearest O.lg. The culmen, t a r s u s , outer primary and number 1 r e c t r i x were measured on each c h i c k to the nearest 0.1mm using Kanon c a l i p e r s f o r the culmen and t a r s i and a p l a s t i c r u l e r f o r p r i m a r i e s and r e c t r i c e s . The methods i n v o l v e d i n the c o l l e c t i o n and analyses of the food data are t r e a t e d by Bedard (1967). D. D i s t r i b u t i o n of North Bering Sea Auklets Breeding c o l o n i e s of the Parakeet, Crested and Least a u k l e t s i n A l a s k a and eastern U.S.S.R. have been de s c r i b e d by Gabrielson and L i n c o l n (1959) and Kozlova (1957), r e s p e c t i v e l y . These d i s t r i b u t i o n s have been r e c e n t l y mapped and analysed by Udvardy (1963). Cychlorrhynchus and A. cr i s t a t e l l a have i d e n t i c a l general ranges (Udvardy, 1963); however, as seen i n Gabrielson and L i n c o l n (1959) and Bedard (1967), the former species has the more ubi q u i t o u s d i s t r i b u t i o n i n the Bering Sea. Cychlorrhynchus nests on the coast of the Chukotsk Peninsula, on the Commander Is l a n d s , i n the Sea of Okhotsk at Ayan, and i n Alaska on the i s l a n d s i n the Bering Sea, and on the A l e u t i a n Islands (Kozlova, .195 7). A. c r i s t a t e l l a breeds on the eastern end of the Chukotsk P e n i n s u l a , t h e D i o m e d e I s l a n d s , S a k h a l i n , a n d t h e c e n t r a l K u r i l e I s l a n d s , i n e a s t e r n S i b e r i a , a n d f r o m t h e P r i b i l o f a n d A l e u t i a n I s l a n d s e a s t t o t h e S h u m a g i n I s l a n d s , A l a s k a (A.O.U. C h i c k - l i s t , 1 9 5 7 : 2 5 4 ) . A. p u s i l l a , e x c l u s i v e l y e n d e m i c t o t h e B e r i n g S e a , s h o w s a d i f f e r e n t b r e e d i n g r a n g e t h a n c r i s t a t e l l a i n t h a t i t d o e s n o t b r e e d o n t h e K u r i l e I s l a n d s a n d s o u t h o f t h e A l e u t i a n I s l a n d s . T h e f o u r t h c l o s e l y r e l a t e d a u k l e t , A. p y g m a e a , w o u l d , a c c o r d i n g t o U d v a r d y ( p . 9 1 ) , " f i t i n t o t h e r a n g e p a t t e r n o f t h e o t h e r t w o A e t h i a a u k l e t s i f we c o u l d c r e d i t C a p t a i n C o o k ' s a c c o u n t a s a w o r t h y d o c u m e n t a t i o n o f i t s f o r m e r n e s t i n g o n t h e I s l a n d s o f t h e B e r i n g S e a . " T h i s s p e c i e s i s p r e s e n t l y r e s t r i c t e d t o t h e e a s t s i d e o f t h e P a c i f i c O c e a n . E. M i g r a t i o n , D i s p e r s a l a n d W i n t e r D i s t r i b u t i o n o f N o r t h B e r i n g S e a A u k l e t s M i g r a t i o n , d i s p e r s a l a n d w i n t e r d i s t r i b u t i o n o f P a r a k e e t , C r e s t e d a n d L e a s t a u k l e t s a r e p o o r l y k n o w n d u e t o t h e i r r e l a t i v e i n a c c e s s i b i l i t y o n t h e i r n e s t i n g g r o u n d s , t h e c o n s e q u e n t l a c k o f b a n d e d b i r d s a n d t h e s c a r c i t y o f o b s e r v a t i o n s o n t h e i r w i n t e r i n g g r o u n d s . T h e p o s t b r e e d i n g d i s p e r s a l o f c h i c k s a n d a d u l t s f r o m t h e S e v u o k u k c o l o n y i s a m a t t e r f o r s p e c u l a t i o n . W h e t h e r t h e y s t a y i n t h e v i c i n i t y o f S t . L a w r e n c e I s l a n d f o r a n y l e n g t h o f t i m e i s n o t k n o w n ; s m a l l f l o c k s o f c r i s t a t e l and p u s i l l a have been seen, however, northwest of Gambell i n l a t e f a l l by walrus hunters (L. Kulukhon, personal communication) but i t i s impossible to be sure that these are part of the St. Lawrence I s l a n d breeding p o p u l a t i o n . Tuck (1961) s t a t e d t h a t f o r the next s e v e r a l weeks a f t e r young and a d u l t murres (Uria spp.) have gone to sea they swim northwards against the c u r r e n t s . Other workers, namely, Johnson (1940), Stechow (1938) , Landsborough-Thomson (1953) and Uspenski (1958) have a l s o demonstrated the r a t h e r wide d i s p e r s a l of U r i a , e s p e c i a l l y young ones a f t e r the breeding season. A u s t i n (1932) found that young Black Guillemots (Cepphus g r y l l e ) a l s o d i s p e r s e d w i d e l y a f t e r the breeding season and i n h i s study of Common P u f f i n s ( F r a t e r c u l a a r c t i c a ) , Lockley (1953:201) s t a t e d t h a t " I t i s s i g n i f i c a n t t h a t j u v e n i l e s e a - b i r d s , as we are d i s c o v e r i n g by r i n g i n g , may perform the longest migrations of t h e i r l i v e s i n t h e i r f i r s t w i n t e r . " The widespread movements of F. a r c t i c a have a l s o been discussed by Landsborough-Thomson (1953) w h i l e the m igrations of R a z o r - b i l l e d Auks (Alca torda) have been studied by Lonnberg (1938), Solomonsen (1944) and Thomson (1953) i n the European A t l a n t i c and by Bedard - (1964) on the American s i d e of the A t l a n t i c Ocean. The decreasing temperature i n l a t e f a l l i n the n o r t h Bering Sea area and the r e s u l t i n g advancing edge 24 of sea i c e which forms i s no doubt l a r g e l y r e s p o n s i b l e f o r the southward movements of p s i t t a c u l a , c r i s t a t e l l a and p u s i l l a out of the St. Lawrence Is l a n d waters i n w i n t e r . The. s.ea i c e forms here about the end of November (Fay and Cade, 1959); the southern l i m i t of f l o a t i n g i c e i n the Bering Sea i s u s u a l l y i n the v i c i n i t y of the P r i b i l o f Islands (U.S. Weather Bureau, 1925). The importance of i c e as a cau s a t i v e f a c t o r i n the movements of a l c i d s i n w i n t e r has been i n d i c a t e d f o r the f o l l o w i n g s p e c i e s : A l c a t o r d a (Bent, 1919), U r i a spp. (Bailey, 1948; Bent, 1919; Salomonsen, 1944; Tuck, 1961; Uspenski, 1958; and o t h e r s ) , Plautus a l l e (Bent, 1919; Uspenski, 1958), Cepphus g r y l l e ( Bailey, 1948; Bent, 1919), C. columba (Bent, 1919), Cychlorrhynchus  p s i t t a c u l a (Bent, 1919), A e t h i a c r i s t a t e l l a (Bent, 1919; Kozlova, 1957), F r a t e r c u l a a r c t i c a (Bent, 1919) and F. c o r n i c u l a t a (Bent, 1919). Cychlorrhynchus has been recorded throughout the winter around the P r i b i l o f Islands (Preble and McAtee, 1923), at Dutch Harbor (Cahn, 1947) and near the A l e u t i a n Islands (Murie, 1959) co n t r a r y to Bent (1919) and Gabrielson and L i n c o l n (195 9). Along the American coast i t has been reported o f f the s t a t e s of Washington (Balmer, 1935) and C a l i f o r n i a (Beck, 1910). On the A s i a t i c s ide of the P a c i f i c Ocean i t has been reporte d i n the K u r i l e Islands, S a k h a l i n a n d H o k k a i d o ( G i z e n k o " , 1 9 5 5 ) a n d S o u t h S a k h a l i n ( S h u n t o v , 1 9 6 5 ) . A. c r i s t a t e l l a a n d n u m b e r s o f A. p u s i l l a w i n t e r n e a r t h e P r i b i l o f I s l a n d s ( P r e b l e a n d M c A t e e , 1 9 2 3 ) a n d a r e b o t h a b u n d a n t a l o n g t h e A l e u t i a n c h a i n ( M u r i e , 1 9 5 9 ) . N e i t h e r c r i s t a t e l l a n o r p u s i l l a t r a v e l s a l o n g t h e A m e r i c a n c o a s t , h o w e v e r , t h e r e i s a r e p o r t o f a n a c c i d e n t a l o c c u r r e n c e o f c r i s t a t e l l a o f f W a s h i n g t o n s t a t e ( N i c k e l s e n , 1 9 4 2 ) . B o t h t h e l a t t e r s p e c i e s a r e common i n w i n t e r i n t h e K u r i l e s ( G i z e n k o , 1 9 5 5 ) , i n t h e S e a o f J a p a n ( S h u n t o v , 1 9 6 5 ) a n d a l o n g t h e s h o r e s o f S a k h a l i n a n d H o k k a i d o ( G i z e n k o , 1 9 5 5 ) . THE BREEDING SEASON CHAPTER I. The Pre-Egg Stage Bedard's (1964) concise d e f i n i t i o n of the pre-egg stage i n a s e a - b i r d colony w i l l be used here, v i z . , the p e r i o d which extends from the time most of the b i r d s have a r r i v e d back at the colony u n t i l the f i r s t egg i s l a i d . A. A r r i v a l of A u k l e t s at the Breeding Colony The a r r i v a l of Parakeet, Crested and Least a u k l e t i n the St. Lawrence I s l a n d waters and on the n e s t i n g slope on Sevuokuk Mountain i n the springs of 1964, 1965 and 1966 have been discussed and t a b u l a t e d by Bedard (1967, t a b l e 1), To h i s t a b l e 1 I have added dates of f i r s t occurrence of each species i n the o f f s h o r e leads and on the n e s t i n g slopes i n 1967 (see t a b l e 5, dates obtained from C. Ray, personal communication). Each species a r r i v e d e a r l i e r i n 1967 than the previous three years.' This i s ~ i n accordance w i t h the e a r l i e r s p r i n g phenology on St. Lawrence I s l a n d i n 1967. Temperature records f o r e a r l y May i n each of the four years are l a c k i n g . L e g e n d f o r T a b l e 5 A r r i v a l d a t e s i n M a y o f a u k l e t s o n S t . L a w r e n c e I s l a n d d u r i n g 1 9 6 4 t o 1 9 6 7 s e a s o n s . D a t a f o r 1 9 6 4 a n d 1 9 6 5 a r e f r o m B e d a r d ( 1 9 6 7 ) , f o r 1 9 6 6 f r o m B e d a r d a n d t h i s s t u d y , f o r 1 9 6 7 f r o m t h i s s t u d y . T A B L E 5 C. p s i t t a c u l a . 1 9 6 4 1 9 6 5 1 9 6 6 1 9 6 7 A. c r i s t a t e l l a 1 9 6 4 1 9 6 5 1 9 6 6 1 9 6 7 A. p u s i l l a 1 9 6 4 1 9 6 5 1 9 6 6 1 9 6 7 F i r s t s e e n i n o f f s h o r e l e a d s 13 9 4 1 8 13 15 10 F i r s t s e e n f r o m s h o r e 15 18 20 15 1 8 20 15 1 8 2 1 F i r s t s e e n o n s l o p e s 1 9 2 1 24 2 0 22 24 1 8 20 22 24 20 28 B. E f f e c t of Snow Cover on the Onset of Nesting The extent and p e r s i s t e n c e of snow cover encountered by a r r i v i n g and s e t t l i n g a u k l e t s on the n e s t i n g slope was c o n s i d e r a t e l y d i f f e r e n t i n 1966 and 1967. In 1966, a l a t e season, snow cover was about 95 percent on the date s e t t l i n g f i r s t occurred ( f i g u r e 4 ) ; i n 1967, an e a r l y season, i t was about 60 percent. The mean temperature at Gambell, two m i l e s west of the Sevuokuk colony, from 21 May to 15 June 1966 was -1.0°C and from 26 May to 15 June 1967 was 7.0°C. As w i l l be seen l a t e r , however, d e s p i t e t h i s temperature d i f f e r e n c e snow cover at the time of egg-laying was the same i n both years; snow was present o n l y along the brow of the mountain ( f i g u r e 6). Snow melts at d i f f e r e n t r a t e s on d i f f e r e n t p a r t s of the slope depending upon exposure and e l e v a t i o n . This r e s u l t s i n p o r t i o n s of the slope being covered w i t h snow, p a r t i c u l a r l y along the brow ( f i g u r e 5), w h i l e the other p o r t i o n s of the slope are f r e e of snow. Thus, at t h i s stage of the breeding c y c l e , the a u k l e t population i s d i v i d e d i n t o those that are c o u r t i n g on the snow and those t h a t are c o u r t i n g on the rocks and a c t u a l l y searching f o r n e s t - s i t e s under them ( f i g u r e 7). The p a t t e r n of egg-laying i n d i f f e r e n t p o r t i o n s of the slope i n r e l a t i o n to exposure to s u n l i g h t was not examined due to the i n a c c e s s i b i l i t y of most n e s t - s i t e s which rendered L e g e n d f o r F i g u r e 4 P a t t e r n o f s n o w - m e l t o n S e v u o k u k M o u n t a i n i n 1 9 6 6 a n d 1 9 6 7 . F i v e p l o t s w e r e s e l e c t e d a t r a n d o m a t d i f f e r e n t e l e v a t i o n s i n a u k l e t n e s t i n g h a b i t a t o n t h e w e s t s l o p e a n d t h r e e o n t h e n o r t h e a s t s l o p e . E a c h p o i n t r e p r e s e n t s m e a n v a l u e o f e s t i m a t e d s n o w - f r e e n e s t i n g h a b i t a t f r o m e a c h p l o t . V a l u e o f 0 i n d i c a t e s s n o w a n d i c e - f r e e n e s t i n g c r e v i c e s . Percent snow-cover on plots 30 L e g e n d f o r F i g u r e 5 S n o w - c o v e r o n w e s t s l o p e o f S e v u o k u k M o u n t a i n , S t . L a w r e n c e I s l a n d , 2 J u n e 1 9 6 7 . N o t e p r e s e n c e o f s n o w - f r e e a n d s n o w - c o v e r e d s l o p e . L e g e n d f o r F i g u r e 6 S e v u o k u k M o u n t a i n , n o r t h e a s t s l o p e , 23 J u n e 1 9 6 7 . N o t e p r e s e n c e o f s n o w o n l y a l o n g t h e r i m . q u a n t i t a t i v e data impossible to o b t a i n . I w i l l t r e a t A. p u s i l l a i n t h i s a n a l y s i s but A. c r i s t a t e l l a i s e q u a l l y i n v o l v e d but C. p s i t t a c u l a , predominantly a c l i f f - n e s t e r i s e f f e c t e d by snow cover to a l e s s e r extent. In 1966 and 1967 snow p e r s i s t e d along the brow of the northeast slope of Sevuokuk Mountain u n t i l about 12 J u l y d e s p i t e the d i f f e r e n c e i n snow melt i n these two years. Comparing egg-laying of A. p u s i l l a (Chapter I I i n 1966 and 1967, an i n t e r e s t i n g s i t u a t i o n i s evident. As may be seen i n f i g u r e 8, t h i s snow on the brow covers much auk l e t n e s t i n g h a b i t a t . Egg-laying i n 1966 spanned the p e r i o d 24 June to 7 J u l y i n those nests s t u d i e d ; those a u k l e t s " s i t t i n g " on the snow on the brow had access to snow-free n e s t i n g h a b i t a t a few days l a t e r and were thus able t o l a y t h e i r eggs almost immediately a f t e r those on the snow-free lower p o r t i o n s of the slope. In 1967, a d i f f e r e n t p a t t e r n of egg-laying e x i s t e d ; the slope and c r e v i c e s were completely f r e e of snow by 8 June ( f i g u r e 4) except f o r that which p e r s i s t e d on the brow u n t i l about 12 J u l y . Higher temperatures duri n g the pre-egg stage i n 1967 r e s u l t e d i n n e s t i n g c r e v i c e s being c l e a r e d of snow e a r l i e r which permitted those a u k l e t s on the snow-free areas t o commence egg-l a y i n g w h i l e the p e r s i s t i n g brow-snow prevented those b i r d s on i t from reaching the n e s t i n g c r e v i c e s . Egg-layin L e g e n d f o r F i g u r e 7 C r e s t e d a n d L e a s t a u k l e t s s e t t l e d o n r o c k s a n d s n o w o n t h e n o r t h e a s t s l o p e o f S e v u o k u k M o u n t a i n , 25 J u n e 1 9 6 7 . N o t e f i d e l i t y o f b i r d s t o s n o w - c o v e r e d r o c k s d e s p i t e p r o x i m a l s n o w - f r e e r o c k s . L e g e n d f o r F i g u r e 8 A u k l e t s ( A e t h i a s p p . ) " s i t t i n g " o n t h e s n o w a t t h e b r o w o f t h e n o r t h e a s t s l o p e o f S e v u o k u k M o u n t a i n , 25 J u n e 1 9 6 7 . N o t e t h e n o n r a n d o m d i s t r i b u t i o n o f b i r d s o n t h e s l o p e . i n 1 9 6 7 s p a n n e d t h e p e r i o d 13 J u n e t o 25 J u n e i n t h o s e n e s t s s t u d i e d o n t h e l o w e r s n o w - f r e e p a r t o f t h e s l o p e ; h o w e v e r , t h e p e r s i s t i n g s n o w o n t h e b r o w r e s u l t e d i n n e s t i n g f a i l u r e o f t h o s e b i r d s f a i t h f u l t o t h a t p a r t o f t h e s l o p e . On 22 J u n e e g g s b e g a n t o b e l a i d o n t h e b r o w s n o w a n d w e r e s u b s e q u e n t l y d e s t r o y e d b e c a u s e t h e y r o l l e d d o w n t h e s n o w a n d b r o k e o r w e r e t a k e n b y g u l l s . O b s e r v a t i o n s o f a u k l e t s s e t t l e d o n t h e s n o w -c o v e r e d s l o p e r e v e a l e d t h a t t h e s c a t t e r i n g o f t h e b i r d s w a s n o t r a n d o m ( f i g u r e 8 ) . I t a p p e a r e d t h a t t h e s e b i r d s , u n c l a s s i f i e d a s t o e x p e r i e n c e d o r i n e x p e r i e n c e d b r e e d e r s , w e r e f a m i l i a r w i t h t h e n e s t i n g s l o p e a n d p o s s e s s e d a h i g h d e g r e e o f l o c a t i o n f o r a p p a r e n t l y n e s t i n g w o u l d o c c u r a m ong t h e b o u l d e r s b e l o w t h e m w h e n t h e s n o w m e l t e d . T h i s a p p a r e n t s e n s e o f l o c a t i o n w a s e x h i b i t e d b y P l a u t u s  a l l e , C e p p h u s c o l u m b a , C. p s i t t a c u l a , A e t h i a s p p . , a n d F r a t e r c u l a a r c t i c a o n S t . L a w r e n c e I s l a n d a n d w a s b o r n e o u t i n A. c r i s t a t e l l a a n d A. p u s i l l a u s i n g b a n d e d a n d c o l o r - m a r k e d a d u l t s c a p t u r e d o n t h e s n o w . T a b l e 6 p r e s e n t s b a n d i n g d a t a a n d s u b s e q u e n t o b s e r v a t i o n s o f t h e s e b i r d s ; f o u r r e t r a p s o f i n c u b a t i n g a d u l t s ( t w o e a c h o f c r i s t a t e l l a a n d p u s i l i a ) p r o v i d e p o s i t i v e e v i d e n c e t h a t t h e y a r e c a p a b l e o f f i n d i n g t h e i r n e s t - s i t e s e v e n w h e n s n o w c o v e r s t h e m . L e g e n d f o r T a b l e 6 B a n d i n g a n d s u b s e q u e n t o b s e r v a t i o n s o f A. c r i s t a t e l l a a n d A. p u s i l l a i n 1 9 6 6 a n d 1 9 6 7 . E a c h a d u l t w a s l i v e -t r a p p e d o n t o p o f t h e s n o w a t a b o u t t h e 20m c o n t o u r o n t h e n o r t h e a s t s l o p e o f S e v u o k u k M o u n t a i n . T h e s u b s e q u e n t o b s e r v a t i o n s w e r e m a d e i n o r n e a r t h e n e s t i n g h a b i t a t w h i c h w a s c o v e r e d b y s n o w w h e n t h e y w e r e b a n d e d . TABLE 6 A c t i v i t y When Species Date Banded Date Observed Observed A. p u s i l l a 15 J u l y 1966 5 J u l y 1966 Incubating egg* A. p u s i l l a 15 June 1966 9 J u l y 1966 Incubating egg* A. p u s i l l a 19 June 1966 3 August 1966 Carrying food t o c h i c k A. c r i s t a t e l l a 15 June 1966 4 August 1966 C a r r y i n g food t o c h i c k A. p u s i l l a 19 June 1966 10 August 1966 Carr y i n g food t o c h i c k A. c r i s t a t e l l a 12 J u l y 1967 15 J u l y 1967 Incubating egg* A. c r i s t a t e l l a 12 June 1967 3 August 1967 Incubating egg* A. c r i s t a t e l l a 12 June 1967 16 August 1967 F l y i n g A. c r i s t a t e l l a 12 June 1967 21 August 1967 Carr y i n g food t o c h i c k O b s e r v a t i o n s supporting the apparent sense of l o c a t i o n possessed by these spe c i e s . C. C o l o n y S t r u c t u r e D r e n t ( 1 9 6 1 ) p o i n t e d o u t t h a t t h e a p p a r e n t " d i s o r d e r l y m o b s " i n a s e a - b i r d c o l o n y a c t u a l l y r e p r e s e n t a w e l l - o r g a n i z e d s y s t e m . V a r i o u s d e s c r i p t i o n s o f C r e s t e d a n d L e a s t a u k l e t c o l o n i e s i l l u s t r a t e t h e a p p a r e n t c h a o t i c s i t u a t i o n w h i c h e x i s t s o n t h e n e s t i n g s l o p e s . On t h e P r i b i l o f I s l a n d s , G a b r i e l s o n a n d L i n c o l n ( 1 9 5 9 : 5 0 6 ) d e s c r i b e d t h e a u k l e t s w h i c h " h a d b e e n s w i r l i n g l i k e s w a r m s o f i n s e c t s , t h e a i r o v e r t h e v i l l a g e w a s f i l l e d w i t h h u r r y i n g f l o c k s , " a n d l a t e r ( p . 5 0 8 ) "As e v e n i n g a d v a n c e d , t h e f l o c k s o f L e a s t A u k l e t s i n c r e a s e d i n s i z e u n t i l t h e c l o u d s o f i n d i v i d u a l s w e r e l i k e t h e g r e a t b l a c k - b i r d s w a r m s o f t h e G u l f C o a s t . T h e s e f l o c k s c i r c l e d a n d s w i r l e d a s r i b b o n s a n d d r i f t s o f b l a c k o r o c c a s i o n a l l y w h i t e , s m o k e o n t h e s k y l i n e o r s h a d o w s o v e r t h e w a t e r , t w i s t i n g a n d t u r n i n g i n f a n t a s t i c f i g u r e s . " N e l s o n ( 1 8 8 7 ) p o r t r a y e d B i g D i o m e d e I s l a n d a s o n l y t o b e l i k e n e d t o a v a s t b e e h i v e , w i t h t h e s w a r m o f b e e s ( a u k l e t s ) h o v e r i n g a b o v e i t . T h e c a r e f u l o b s e r v e r s o o n r e a l i z e s t h a t " o r d e r o u t o f c h a o s " d o e s p r e v a i l i n a n a u k l e t c o l o n y . H o w e v e r , o n l y a s k e t c h o f t h e s o c i a l s t r u c t u r e i n P a r a k e e t , C r e s t e d , a n d L e a s t a u k l e t s c a n b e o f f e r e d s i n c e m a r k e d n o n - b r e e d e r s a n d a d u l t s w e r e u n a v a i l a b l e o r t o o f e w t o a l l o w m e a n i n g f u l o b s e r v a t i o n s t o b e m a d e . I t a p p e a r s f r o m t h e l i m i t e d d a t a a v a i l a b l e t h a t y e a r - t o - y e a r s t a b i l i t y w i t h i n t h e c o l o n y e x i s t s ; t h e m a t e d p a i r s r e m a i n i n t a c t i n s u c c e s s i v e y e a r s a n d u s e t h e s a m e n e s t - s i t e s a s l o n g ; a s t h e y r e m a i n u n d i s t u r b e d . Y e a r l i n g b i r d s a r e p r e s e n t i n t h e c o l o n y b u t i t i s n o t k n o w n i f t h e y r e t u r n t o t h e i r b i r t h p l a c e . T w o - y e a r - o l d b i r d s a r e a l s o p r e s e n t , h o w e v e r , i t a p p e a r s t h a t t h e y d o n o t b r e e d ; w h e t h e r a u k l e t s f i r s t b r e e d i n t h e i r t h i r d y e a r i s u n c e r t a i n ( B e d a r d , 1 9 6 7 ) . a . P a i r - b o n d i n a u k l e t s T h e s m a l l s a m p l e o f b a n d e d a n d r e c a p t u r e d a d u l t s i n c u b a t i n g e g g s p r o v i d e s e v i d e n c e t h a t m a f c e - r e t e n t i o n o c c u r s b u t d o e s n o t a l l o w o n e t o s a y t h a t . i t i s t h e g e n e r a l r u l e i n t h e a u k l e t s . T h r e e p a i r s i o f A. p u s i l i a ( n e s t s #37, 8 2 , a n d 1 5 1 ) a n d o n e p a i r o f M.. c r i s t a t e l l a ( n e s t #19) w e r e b a n d e d i n 1 9 6 6 . Two p a i r s o f A. p u s i l l a ( n e s t s #3 7 a n d 1 5 1 ) a n d t h e p a i r o f A. c r i s t a t e l l a w e r e r e c a p t u r e d i n 1 9 6 7 i n t h e same n e s t — s i t e s . One o f t h e t h i r d p a i r o f A. p u s i l l a ( n e s t #82 ) ) w a s c a u g h t i n 1 9 6 7 . T h e i m m e n s e n u m b e r o f b r e e d i n g a u k l e t s i n t h i s c o l o n y p r e c l u d e d t h e d i s c o v e r y ( w i t h o u t Im<ck) o f n e s t -s i t e c h a n g e s o r " d i v o r c e " c a s e s ( s e e D r e m t t , 1 9 6 5 ) . _C. p s i t t a c u l a p r o b a b l y r e t a i n s t h e s a m e m a t e s m o r e t h a n o n e s e a s o n , h o w e v e r , s i n c e n o n e w a s b a n d e x d i n 1 9 6 6 i t i s n o t p o s s i b l e t o b e s u r e . C a p t u r e o f a d u l t s o n a c c e s s i b l e n e s t s w a s t h e m e t h o d o f b a n d i n g , a n d i s f a c i l i t a t e d b y t h e n a t u r e o f s ome o f t h e n e s t - s i t e s w h i c h g e n e r a l l y c o n f i n e t h e a d u l t a n d e n a b l e o n e t o c a t c h i t b y h a n d . R e c a p t u r e w a s b y t h e s a m e m e t h o d . In t h e o t h e r a u k s , m a t e r e t e n t i o n h a s b e e n r e c o r d e d i n U r i a a a l g e a n d U. l o m v i a ( T u c k , 1 9 6 1 ) , C e p p h u s c o l u m b a ( D r e n t , 1 9 6 5 ) a n d C e r o r h i n c a m o n o c e r a t a ( R i c h a r d s o n , 1 9 6 1 ) . T h e s i t u a t i o n m e n t i o n e d i n C_. c o l u m b a , w h e r e t h e b i r d s g e n e r a l l y p a i r f o r s e v e r a l y e a r s b u t d i v o r c e may o c c u r ( D r e n t , 1 9 6 5 ) , h a s a l s o b e e n r e p o r t e d i n U. l o m v i a ( U s p e n s k i , 1 9 5 8 ) . b . N e s t - s i t e t e n a c i t y F r o m t h e p r e c e d i n g s e c t i o n i t w a s f o u n d t h a t C r e s t e d a n d L e a s t a u k l e t s u s e t h e s a m e n e s t - s i t e s o f t h e p r e v i o u s y e a r . T h r e e p a i r s o f A. p u s i l l a ( n e s t s #37, 8 2 a n d 1 5 1 ) a n d o n e a d u l t f r o m e a c h o f t w o p a i r s ( n e s t s #32 a n d 5 7 ) w e r e b a n d e d i n 1 9 6 6 ; o n e p a i r o f A. c r i s t a t e l l a ( n e s t #19) w a s a l s o b a n d e d t h a t y e a r . R e c a p t u r e s i n 1 9 6 7 s h o w e d t h e f o l l o w i n g r e s u l t s : h.- p u s i l l a : N e s t #37 - p a i r p r e s e n t N e s t #82 - o n e a d u l t p r e s e n t N e s t # 1 5 1 - p a i r p r e s e n t N e s t #32 - p r e s e n t N e s t #57 - n e s t c r e v i c e d e s t r o y e d A. c r i s t a t e l l a : N e s t #19 - p a i r p r e s e n t O b s e r v a t i o n s o f a u k l e t s o n t h e s n o w d u r i n g t h e p r e - e g g s t a g e l e a d me t o c o n c l u d e t h a t n e s t - s i t e t e n a c i t y i s h i g h l y d e v e l o p e d i n P a r a k e e t , C r e s t e d a n d L e a s t a u k l e t s . A s d i s c u s s e d e a r l i e r i n t h i s c h a p t e r , a u k l e t s a r r i v e o n t h e s l o p e s a n d d i s t r i b u t e t h e m s e l v e s o n t o p o f t h e s n o w . T h i s d i s t r i b u t i o n a n d s u b s e q u e n t b e h a v i o r ( p a i r i n g h a d o c c u r r e d i n m o s t c a s e s b y t h i s t i m e ) i n d i c a t e d t h a t t h e y p o s s e s s e d a h i g h d e g r e e o f l o c a t i o n . T h e a d a p t i v e v a l u e o f t h i s n e s t - s i t e t e n a c i t y b e c o m e s a p p a r e n t w h e n t h e p a t t e r n o f s n o w m e l t f r o m t h e s l o p e i s s t u d i e d . S n o w d i s a p p e a r s f r o m t h e s l o p e a t d i f f e r e n t r a t e s i n d i f f e r e n t p o r t i o n s o f t h e s l o p e w h i c h r e s u l t s i n a r e a s o f s n o w - f r e e a n d s n o w - c o v e r e d n e s t i n g h a b i t a t a d j a c e n t t o e a c h o t h e r ( f i g u r e 7 ) . E g g - l a y i n g i n r e l a t i o n t o s n o w m e l t w a s s t u d i e d i n s e v e r a l n e s t - s i t e s i n 1 9 6 7 a n d w a s f o u n d t o o c c u r i n m a n y c a s e s w i t h i n a f e w d a y s a f t e r t h e c r e v i c e w a s f r e e o f s n o w . T h e f o l l o w i n g o b s e r v a t i o n s i l l u s t r a t e t h i s p o i n t m o r e c l e a r l y : _C. p s i t t a c u l a n e s t #14, e l e v a t i o n a p p r o x i m a t e l y 120m, n o r t h e a s t s l o p e ; p a i r d i s p l a y i n g o n s n o w d i r e c t l y o v e r n e s t c r e v i c e a t 0 3 0 0 h r o n 3 J u l y . A t 0 1 0 0 h r o n 6 J u l y t h e c r e v i c e w a s d e v o i d o f s n o w a n d o c c u p i e d b y t h e p a i r . On 7 J u l y a t 1 8 3 0 h r a n e g g w a s p r e s e n t . A. c r i s t a t e l l a n e s t #32, e l e v a t i o n a p p r o x i m a t e l y 30m, n o r t h e a s t s l o p e ; c o v e r e d w i t h s n o w o n 22 J u n e . E g g p r e s e n t a t 0 2 3 0 h r o n 25 J u n e . A. p u s i l l a n e s t #29, e l e v a t i o n a p p r o x i m a t e l y 75m, n o r t h e a s t s l o p e ; c o v e r e d w i t h s n o w o n 22 J u n e . A t 0 1 0 0 h r o n 24 J u n e a n e g g w a s p r e s e n t i n t h e n e s t - s i t e . T h e s e o b s e r v a t i o n s s h o w t h a t d e s p i t e t h e f a c t t h a t s n o w m e l t may o c c u r a t d i f f e r e n t t i m e s e a c h y e a r (three weeks e a r l i e r i n 1967 compared to 1966), there i s reduced competition f o r n e s t - s i t e s which could be time consuming and c r i t i c a l i f a l l b i r d s competed f o r n e s t - s i t e s at the f i r s t a v a i l a b l e snow-free areas as i n the case of Brant (Branta b e r n i c l a ) (Barry, 1962) . As pointed out by Drent (1965), a l l species of auk s t u d i e d show a pronounced n e s t - s i t e t e n a c i t y : A l c a t o r d a (Landsborough-Thomson, 1953; Kartaschew, 1960), U r i a aalge (Storer, 1952; Landsborough-Thomson, 1953; Tschanz, 1959; Kartaschew, 1960; Tuck, 1961), U. lomvia (Uspenski, 1958; Kartaschew, 1960), Cepphus g r y l l e (Storer, 1952), C. columba (Drent, 1965), F r a t e r c u l a  a r c t i c a (Landsborough-Thomson, 1953) and Cerorhinca  monocerata (Richardson, 1961). c. T e r r i t o r i a l i t y As suggested by Bedard (1967), these a u k l e t s are presumed to be t e r r i t o r i a l and t o defend a s i n g l e i n t e r s t i c e or n e s t - s i t e (Type "C" t e r r i t o r y of Hinde, 1956). The e f f e c t i v e n e s s of t h i s n e s t - s i t e defence i s i n d i c a t e d by the f a c t t h a t , d e s p i t e the immense number of n e s t i n g a u k l e t s i n t h i s colony, they u t i l i z e the same nest year a f t e r year. Evidence f o r t h i s t e r r i t o r i a l i t y was, however, d i f f i c u l t to o b t a i n f o r i t i s impossible to observe the b i r d s ' behavior on t h e i r n e s ts. This d i f f i c u l t y a l s o precluded determining whether, during 40 the chick-rearing stage, t h i s intolerance declined as i s the case in F_. a r c t i c a (Lockley, 1953) . Other a l c i d s exhibit a similar type of t e r r i t o r i a l i t y (Drent, 1965 in C_. columba; Lockley, 1953 in F. a r c t i c a ; Thoresen, 1964 in Ptychoramphus al e u t i c a ) , and defend the approach to t h e i r respective n e s t - s i t e s (Bedard, 1964 in A. torda). d. Non-breeders Observations on non-breeding auklets are in conformance with those of Bedard (1967) and do not add s i g n i f i c a n t l y to h i s description (p. 14-16) . D. Copulation Copulation or attempted copulation in auklets was observed only once at sea (Bedard, personal correspondence) and never on the surface of the nesting slopes (Bedard, 1967; t h i s study). Bedard f e l t that i t would be surprising i f i t could occur in such places owing to the peculiar intruding system involving non-breeders and to the fact that immature birds would quickly disrupt and prevent e f f i c i e n t copulation in such sit u a t i o n s . Except in one .instance, observations in t h i s study support Bedard who found copulation to probably occur in the ne s t - s i t e . As discussed e a r l i e r , many auklets l a i d eggs on top of the snow in 1967; i n t e r n a l examination of several of these Aethia eggs revealed the presence of a blastodisc i n t h r e e c r i s t a t e l l a a n d t w o p u s i l l a e g g s w h i c h i n d i c a t e s t h a t c o p u l a t i o n a n d f e r t i l i z a t i o n h a d t a k e n p l a c e . S e v e r a l o t h e r A e t h i a e g g s l a i d o n t h e s n o w w e r e i n f e r t i l e T h i s c o p u l a t i o n p o s s i b l y t o o k p l a c e a t s e a f o r a b o u t 5 5 h r o f o b s e r v a t i o n s o f a u k l e t s o n t h e s n o w s h o w e d n o c o p u l a t o r y a c t s c a r r i e d o u t t h e r e . C o p u l a t i o n , a s w e l l a s o t h e r b e h a v i o r o n t h e n e s t w a s u s u a l l y i m p o s s i b l e t o o b s e r v e b e c a u s e i t o c c u r r e d i n t h e d a r k r e c e s s e s o f t h e n e s t - s i t e a n d i n t h e t h r e e i n s t a n c e s w h e r e i t w a s b r i e f l y o b s e r v e d t h i s w a s a c c o m p l i s h e d b y a c c i d e n t w h i l e s e a r c h i n g f o r a c t i v e n e s t s w i t h a f l a s h l i g h t . I n e a c h c a s e t h e p r e s u m e d m a l e w a s m o u n t e d o n t h e b a c k o f t h e f e m a l e i n a m a n n e r s i m i l a r t o t h a t d e s c r i b e d f o r C e p p h u s ( D r e n t , 1 9 6 5 ) . I n e a c h o f t h e s e o b s e r v a t i o n s , t w o o f c r i s t a t e l l a a n d o n e o f p u s i l l a , t h e b i r d s " f r o z e " i m m e d i a t e l y u p o n b e i n g s t r u c k b y t h e l i g h t a n d c e a s e d a l l f o r m s o f s e x u a l b e h a v i o r . O b s e r v a t i o n s p r e s e n t e d i n t h e s e c t i o n o n p a i r - b o n d s h o w t h e a p p a r e n t s h o r t t i m e i n v o l v e d b e t w e e n s n o w m e l t a n d e g g - l a y i n g i n some p a i r s ; c o p u l a t i o n p r o b a b l y o c c u r s w i t h i n t h i s p e r i o d . D r e n t ( 1 9 6 5 ) o b s e r v e d c o p u l a t i o n i n C. c o l u m b a u p t o 28 d a y s p r i o r t o l a y i n g t h e f i r s t e g g ; t h e r a t e o f c o p u l a t i o n j u m p e d t o a m a x i m u m i n a p p r o x i m a t e l y t h e l a s t 12 d a y s p r i o r t o e g g - l a y i n g . T h e t i m e e l a p s i n g b e t w e e n c o p u l a t i o n a n d t h e f i r s t f e r t i l egg obtained i n chickens has been reported by many i n v e s t i g a t o r s (see review by Parker, 1949) . The time averages about 72 hours, but may be as low as 19.5 hours, according t o one r e p o r t . The l a t t e r f i g u r e , i f c o r r e c t , means th a t the egg may be f e r t i l i z e d w h i l e i t i s i n the magnum or isthmus (Sturkie, 1965). Provided t h a t a u k l e t s possess s i m i l a r c a p a b i l i t i e s regarding f e r t i l i z a t i o n and l a y i n g , i t would be p o s s i b l e f o r eggs to be f e r t i l i z e d and l a i d i n n e s t - s i t e s t h a t have been f r e e of snow f o r on l y three or four days. The l a c k of observations of the sequence of events preceding, during and f o l l o w i n g c o p u l a t i o n i n auklets precludes a general comparison w i t h other auks; however, a few p o i n t s are of i n t e r e s t . Copulation i n A l c a and Cepphus, which takes place on land, has been described by Bedard (1964) and Drent (1965), r e s p e c t i v e l y . The former species copulates i n t h e i r n e s t - s i t e s w h i l e the l a t t e r species u t i l i z e s t h e i r beach p e r c h - s i t e s . In U r i a spp. c o p u l a t i o n a l s o occurs on the n e s t - s i t e (Storer, 1952; Tuck, 1961) and only i n r a r e cases does i t occur on water (Tuck, 1961) ; the l a t t e r s i t e provides the s i t e f o r c o p u l a t i o n i n _F. a r c t i c a (Fisher and Lockley, 1954; Myrberget, 1962). Nothing i s known about the v o c a l i z a t i o n s , i f any occur, u t t e r e d by a u k l e t s during c o p u l a t i o n as i s common i n some a l c i d s , e.g. Cepphus ( D r e n t , 1 9 6 5 ) , U r i a s p p . ( T u c k , 1 9 6 1 ) a n d A l c a ( B e d a r d , 1 9 6 4 ) . C H A P T E R I I . T h e E g g S t a g e A. T h e N e s t s o f P a r a k e e t , C r e s t e d a n d L e a s t A u k l e t s a . D e s c r i p t i o n o f t h e n e s t i n g e n v i r o n m e n t T h e p l a n k t o n - f e e d i n g a l c i d s a r e i n t i m a t e l y a s s o c i a t e d w i t h t a l u s s l o p e s d u r i n g t h e b r e e d i n g s e a s o n o n S t . L a w r e n c e I s l a n d . H e r e , r o c k , i n v a r y i n g d e g r e e s o f d i s i n t e g r a t i o n a n d p o s i t i o n o n t h e s l o p e , p r o v i d e s t h r o u g h p h y s i c a l c o n t a c t w i t h e a c h o t h e r t h e c r e v i c e s a n d i n t e r s t i c e s u t i l i z e d b y a u k l e t s a s n e s t i n g s i t e s . T a l u s s l o p e s o r s c r e e a r e p r o d u c e d m a i n l y b y w e a t h e r i n g o f c l i f f s w h i c h i s a i d e d b y m a s s - w a s t i n g , t h e b u l k t r a n s f e r o f m a s s e s o f r o c k d e b r i s d o w n s l o p e s u n d e r t h e d i r e c t i n f l u e n c e o f g r a v i t y . T a l u s may b e f o r m e d b y f r o s t a c t i o n , a f o r m o f w e a t h e r i n g , w h i c h a c t s o n a c l i f f - f a c e r e s u l t i n g i n r o c k b r e a k i n g a t t h e l e v e l o f t h e j o i n t s . U p o n b r e a k i n g a w a y f r o m t h e p a r e n t r o c k t h e l o o s e p a r t i c l e t u m b l e s d o w n t h e s l o p e d u e t o t h e g r a v i t a t i o n a l p u l l a n d c o m e s t o r e s t a t t h e b o t t o m o f t h e s l o p e . C o n t i n u e d a c c u m u l a t i o n o f r o c k d e b r i s a t t h e b o t t o m o f t h e s l o p e , p r o v i d e d w a v e a c t i o n o r i c e s c o u r i n g d o n o t r e m o v e t h e p a r t i c l e s , r e s u l t s i n t h e t a l u s c r e e p i n g o r r e t r e a t i n g u p w a r d s . E v e n t u a l l y , i f t h e r o c k w a s t e a c c u m u l a t e s m o r e r a p i d l y t h a n i t c a n b e d e s t r o y e d o r r e m o v e d , e v e n t h e u p p e r c l i f f s b e c o m e b u r i e d , a n d t h e g r o w t h o f t h e t a l u s c e a s e s . T h e s l o p e a n g l e o f t h e t a l u s v a r i e s w i t h t h e s i z e a n d s h a p e o f t h e r o c k f r a g m e n t s ( L e e t a n d J u d s o n , 1 9 6 5 ) ; t h e a n g l e o f t h e t a l u s s l o p e o n S e v u o k u k M o u n t a i n i s a b o u t 3 0 d e g r e e s , d e p e n d i n g u p o n w h e r e t h e m e a s u r e m e n t w a s m a d e . F o r a d e t a i l e d d e s c r i p t i o n o f t h e n e s t i n g s l o p e s on" S e v u o k u k M o u n t a i n t h e r e a d e r i s r e f e r r e d t o B e d a r d ( 1 9 6 7 ) . T h e m i c r o - e n v i r o n m e n t u t i l i z e d by A e t h i a s p p . f o r n e s t i n g p u r p o s e s i s t h e m a n t l e o f r o c k d e b r i s t h a t c o v e r s e n t i r e s l o p e s o r p a r t s o f s l o p e s . T h e m a n t l e , a c c o r d i n g t o B e d a r d ( 1 9 6 7 ) , i s t h e c o v e r i n g o f c o b b l e s a n d b o u l d e r s o n t a l u s s l o p e s . I t i s l i m i t e d i n t h i c k n e s s b y t h e i n t e r - f a c e a i r - s l o p e o n o n e h a n d , a n d b y t h e " f l o o r " o n t h e o t h e r a n d d o e s n o t g e n e r a l l y e x c e e d f i v e m e t e r s i n t h i c k n e s s . T h e f l o o r o r l o w e r l i m i t o f t h e m a n t l e i s made o f t h e u n f r a c t u r e d p a r e n t r o c k o r , m o r e o f t e n , i s t h e r e s u l t o f t h e a c c u m u l a t i o n a n d s e t t l i n g o f f i n e p a r t i c l e s w i t h t h e p r o d u c t i o n o f a r e l a t i v e l y f l a t o r u n i f o r m s u r f a c e ( B e d a r d , 1 9 6 7 ) . I t i s n e c e s s a r y a t t h i s s t a g e t o p o i n t o u t t h a t i t w a s i m p o s s i b l e t o h a v e a c c e s s t o a l l n e s t s o f A e t h i a s p p . i n t h e r o c k m a n t l e o r e v e n a g i v e n s e c t o r o f t h e m a n t l e . W i t h o u t m a n i p u l a t i n g a n d c o n s e q u e n t l y d e s t r o y i n g n e s t i n g h a b i t a t , o n e w a s u n a b l e t o r e a c h a n d o b s e r v e m o s t o f t h e n e s t s . C o n s e q u e n t l y , t h o s e n e s t s s t u d i e d 4 6 were a c c e s s i b l e because of t h e i r m a r g i n a l l o c a t i o n or t h e i r nearness t o the s u r f a c e o f the mantle. I t was found t h a t n e s t s would be d e s e r t e d i f adj a c e n t r o c k s were removed t o p r o v i d e access f o r study purposes even though they were r e p l a c e d as c l o s e l y to t h e i r o r i g i n a l p o s i t i o n as p o s s i b l e . T h i s p r e c l u d e d o b t a i n i n g much important i n f o r m a t i o n such as: d i f f e r e n t i a l e g g - l a y i n g on d i f f e r e n t p a r t s o f the slope, the e f f e c t s of s o c i a l s t i m u l a t i o n on e g g - l a y i n g , p r o d u c t i o n s t a t i s t i c s , impact of p r e d a t i o n , pre-sea-going m o r t a l i t y , e t c . On Walrus I s l a n d , Bent (1919) found Parakeet, C r e s t e d and Least a u k l e t s n e s t i n g under l o o s e p i l e s of water-worn b o u l d e r s which were p i l e d up i n a g r e a t r i d g e . in the b e a c h l i k e c e n t r e o f the Isl a n d , c o n n e c t i n g the hi g h e r e x t r e m i t i e s . On the P r i b i l o f s , Parakeet A u k l e t s u s u a l l y l a y t h e i r eggs beneath l a r g e b o u l d e r s or i n p r a c t i c a l l y i n a c c e s s i b l e c a v i t i e s i n the c l i f f s ; i n some cases the eggs are d e p o s i t e d i n burrows a p p a r e n t l y excavated i n the loose s o i l t o p p i n g the v o l c a n i c c l i f f s (Preble and McAtee, 1923). Murie (1959) d e s c r i b e d Parakeet's n e s t i n g h a b i t a t i n the A l e u t i a n s as b e i n g among l a r g e b o u l d e r s on the beach, i n c r e v i c e s i n r o c k y c l i f f s and on s l o p e s where rocks are p a r t l y covered by v e g e t a t i o n . Cade (1952) found a s i n g l e p a i r i n h a b i t i n g a burrow under loo s e rocks which had f a l l e n down from the c l i f f s and p i l e d up i n a mass at the water's edge on Sledge I s l a n d . On t h e C o m m a n d e r I s l a n d s , S t e j n e g e r ( 1 8 8 5 ) f o u n d P a r a k e e t A u k l e t s b r e e d i n g i n s t e e p , c r a c k e d a n d i n a c c e s s i b l e r o c k s . T u r n i n g t o t h e C r e s t e d A u k l e t , a c c o r d i n g t o P r e b l e a n d M c A t e e ( 1 9 2 3 ) , o n t h e P r i b i l o f s t h i s s p e c i e s u s u a l l y n e s t s a b o u t t h e h i g h c l i f f s . T h e s i n g l e w h i t e e g g i s d e p o s i t e d i n d e e p a n d u s u a l l y i n a c c e s s i b l e r e c e s s e s ; o c c a s i o n a l l y t h e b i r d s l a y t h e i r e g g s i n t h e d e p t h s o f b o u l d e r b e a c h e s . On t h e A l e u t i a n I s l a n d s , t h e y n e s t d e e p i n c r e v i c e s a m o n g b o u l d e r s o n t h e b e a c h , i n c a v i t i e s i n c l i f f s o r a m o n g j u m b l e d l a v a r o c k o n h i g h s l o p e s ( M u r i e , 1 9 5 9) . K o z l o v a ( 1 9 5 7) s t a t e d t h a t C r e s t e d s n e s t a m ong c l i f f s a n d s t o n e h e a p s o n t h e s e a -c o a s t , f r e q u e n t l y i n c o m p a n y o f P a r a k e e t A u k l e t s ; t h e s i n g l e w h i t e e g g i s l a i d b e t w e e n s t o n e s , w i t h o u t l i n i n g , o r i n s i d e a d e e p c r e v i c e o f a c l i f f . N e s t i n g o f L e a s t A u k l e t s o n t h e A l e u t i a n s a n d w e s t c o a s t o f U.S.S.R. h a s b e e n d e s c r i b e d b y M u r i e ( 1 9 5 9 ) a n d K o z l o v a ( 1 9 5 7 ) , r e s p e c t i v e l y a s b e i n g s i m i l a r t o C r e s t e d A u k l e t s . D u r i n g t h i s s t u d y . a b o u t 8 0 0 n e s t s o f A e t h i a s p p . a n d a b o u t 6 0 n e s t s o f C y c h l o r r h y n c h u s w e r e e x a m i n e d . D e s p i t e t h e f a c t t h a t t h e p e r c e n t a g e o f n e s t s i n e a c h n e s t - t y p e c a t e g o r y c a n n o t b e g i v e n d u e t o t h e i r g e n e r a l i n a c c e s s i b i l i t y i t i s f e l t t h a t a l l e x i s t i n g n e s t - t y p e s f o r e a c h s p e c i e s i n t h e S e v u o k u k c o l o n y h a v e b e e n o b s e r v e d . 48 C y c h l o r r h y n c h u s o c c u p i e s t h e s ame g e n e r a l n e s t i n g h a b i t a t o n S t . L a w r e n c e I s l a n d a s d e s c r i b e d b y t h e a b o v e w r i t e r s ; h o w e v e r , A e t h i a s p p . w i l l b e s h o w n t o h a v e a m o r e c o m p l e x n e s t i n g d i s t r i b u t i o n t h a n o n e i s l e d t o b e l i e v e b y t h e i r d e s c r i p t i o n s . N e i t h e r C r e s t e d n o r L e a s t a u k l e t s a c c u m u l a t e n e s t i n g m a t e r i a l b u t i n s t e a d l a y t h e i r e g g s u n d e r t h e b o u l d e r s o n t h e f l o o r o f t h e m a n t l e o r i n a c r e v i c e f o r m e d a t t h e a n g l e c r e a t e d b y c o n t a c t o f t w o o r m o r e b o u l d e r s . C y c h l o r r h y n c h u s a l s o d o e s n o t a c c u m u l a t e n e s t i n g m a t e r i a l . M o s t e g g s o f e a c h s p e c i e s w e r e l a i d o n d i r t b u t i n some n e s t s s m a l l p e b b l e s a c c u m u l a t e d o n t h e f l o o r s u p o n w h i c h t h e e g g s w e r e d e p o s i t e d . F i g u r e s 9, 10 a n d 1 1 i l l u s t r a t e t h e t y p e s o f P a r a k e e t , C r e s t e d a n d L e a s t a u k l e t n e s t s , r e s p e c t i v e l y , e n c o u n t e r e d i n t h e S e v u o k u k c o l o n y . I n e v e r y n e s t e x a m i n e d t h e e g g w a s i n n e a r t o t a l d a r k n e s s a n d a l w a y s u n d e r a r o c k o r p e a t . b . S e g r e g a t i o n o n t h e n e s t i n g s l o p e D u r i n g a s t u d y o f e c o l o g i c a l s e g r e g a t i o n a m o n g C y c h l o r r h y r i c h u s a n d A e t h i a s p p . , Bedard ( 1 9 6 7 ) d e m o n s t r a t e d t h a t s e g r e g a t i o n o n t h e n e s t i n g s l o p e i s c o m p l e t e b e t w e e n t h e t w o g e n e r a , C y c h l o r r h y n c h u s b e i n g p r i m a r i l y a s c a r p -f a c e n e s t e r w h i l e A e t h i a s p p . o c c u p y t h e t a l u s s l o p e s . I n t h e l a t t e r h a b i t a t , Bedard ( 1 9 6 7 ) l o o k e d a t o n e a s p e c t o f t h e r e l a t i o n s b e t w e e n a u k l e t s a n d t h e n e s t i n g e n v i r o n m e n t . U s i n g c o n c e p t s o f s l o p e m o r p h o l o g y a n d s l o p e 49 Legend for Figure 9 Cross-sections of main nest types of Parakeet Auklets on Sevuokuk Mountain, St. Lawrence Island. S t i p p l i n g indicates s o i l ; clear portions indicate rock. A B A crack in a scarp B in mantle covered by vegetation C under large boulder D crevice among splintered parent rock 5 0 L e g e n d f o r F i g u r e 10 C r o s s - s e c t i o n s o f m a i n n e s t t y p e s o f C r e s t e d A u k l e t s o n S e v u o k u k M o u n t a i n , S t . L a w r e n c e I s l a n d . S t i p p l i n g i n d i c a t e s s o i l ; c l e a r p o r t i o n s i n c i d a t e r o c k . A under stones B in mantle covered by vegetation C in interstices (top view) Legend f o r F i g u r e 11 C r o s s - s e c t i o n s o f main n e s t t y p e s o f L e a s t A u k l e t s on Sevuokuk Mountain, S t . Lawrence I s l a n d . S t i p p l i n g i n d i c a t e s s o i l ; c l e a r p o r t i o n s i n d i c a t e r o c k . A B p r o c e s s e s , h e s h o w e d t h e p a t t e r n s o f s e g r e g a t i o n b e t w e e n t h e t w o s p e c i e s o f A e t h i a a n d g a v e some e v i d e n c e t o t h e e f f e c t t h a t b r o a d - s c a l e g e o m o r p h i c p r o c e s s e s c a n a f f e c t t h e o v e r a l l a b u n d a n c e a n d r e l a t i v e p r o p o r t i o n s o f t h e s e t w o s p e c i e s i n v a r i o u s p a r t s o f t h e i r b r e e d i n g r a n g e s . H e d e m o n s t r a t e d t h a t t h e m a r k e d d i f f e r e n c e i n b o d y s i z e b e t w e e n A. c r i s t a t e l l a a n d A. p u s i l i a i s r e s p o n s i b l e f o r s e g r e g a t i o n , a c t i n g t h r o u g h o n e p r i n c i p a l f a c t o r , t h e a v e r a g e r o c k d i a m e t e r o n t h e s l o p e s . H i s t h e s i s i s t h a t t h e d e n s i t y o f c r i s t a t e l l a i n c r e a s e s l i n e a r l y w i t h i n c r e a s i n g b o u l d e r s i z e ; t h e d e n s i t y o f p u s i l i a d e c r e a s e s b o t h w i t h d e c r e a s i n g b o u l d e r s i z e a n d w i t h d e c r e a s i n g a b u n d a n c e o f i t s l a r g e r c o n g e n e r . T o i l l u s t r a t e t h i s s e g r e g a t i o n I h a v e u t i l i z e d f i g u r e 3 8 o f B e d a r d (my f i g u r e 12) a n d h i s d i s c u s s i o n o f i t . T h e l e f t p a r t o f t h e c u r v e f o r p u s i l l a f a l l s v e r y a b r u p t l y a f t e r r e a c h i n g a m a x i m u m r o c k - s i z e d i a m e t e r o f a b o u t 3 . 0 d c m . T h i s p a r t o f t h e c u r v e h a s n o t b e e n d o c u m e n t e d b u t r a t h e r h a s b e e n d r a w n f r o m q u a l i t a t i v e o b s e r v a t i o n s . A d e c r e a s e i n t h e a v e r a g e s i z e o f t h e p a r t i c l e s i s g e n e r a l a c c o m p a n i e d b y c l o g g i n g o f t h e i n t e r s t i c e s , s o i l f o r m a t i o n a n d v e g e t a t i o n d e v e l o p m e n t ; s u c h c o n d i t i o n s d e v e l o p r a t h e r r a p i d l y b e t w e e n m e a n v a l u e s o f 3.0 a n d 2 . 0 d c m . A t t h e o t h e r e x t r e m e o f t h e g r a p h , i n t h e d o m a i n o f c r i s t a t e l l a , t h e r e i s a n o b v i o u s l i m i t t o t a l u s s l o p e f o r m a t i o n w i t h p a r t i c l e s e x c e e d i n g a n a v e r a g e d i a m e t e r b f l O . O d c m ; 53 L e g e n d f o r F i g u r e 12 G e n e r a l i z e d m o d e l s h o w i n g t h e s e g r e g a t i o n b e t w e e n A e t h i a c r i s t a t e l l a a n d A. p u s i l i a o n t h e n e s t i n g s l o p e s a c c o r d i n g t o a v e r a g e r o c k d i a m e t e r . F r o m B e d a r d ( 1 9 6 7 : 1 2 3 ) . 54 t h i s may o c c u r i n some a r e a s b u t i n t h e S e v u o k u k c o l o n y s u c h l a r g e b l o c k s a c c u m u l a t e d a t t h e b a s e o f t h e t a l u s s l o p e t o f o r m t h e " r u b b l e " . I f t h e s e b l o c k s a r e l a r g e e n o u g h , t h e y w i l l r e s i s t r e m o v a l b y w a v e a n d i c e a c t i o n w h i l e t h e f i n e r p a r t i c l e s w i l l b e r e m o v e d b e t w e e n t h e m . A t a n y r a t e , t h i s h a b i t a t i s u s u a l l y o c c u p i e d b y o t h e r a l c i d s s u c h a s C e p p h u s a n d o f t e n , F r a t e r c u l a . F u r t h e r m o r e , t h e i n c r e a s e i n p a r t i c l e s i z e a b o v e a c e r t a i n l i m i t b r i n g s a b o u t a d i r e c t d e c r e a s e i n t h e p o s s i b l e n u m b e r o f i n t e r s t i c e s a n d t h i s p r o b a b l y a c c o u n t s f o r m u c h o f t h e d r o p t h a t o c c u r s i n t h e d e n s i t y o f c r i s t a t e l l a b e t w e e n v a l u e s o f a v e r a g e r o c k d i a m e t e r o f 7.0 t o l O . O d c m A s p o i n t e d o u t b y B e d a r d a n d o b s e r v e d i n t h i s s t u d y , i t b e c o m e s p o s s i b l e e v e n a f t e r s h o r t f i e l d e x p e r i e n c e i n t h i s a l c i d c o l o n y t o r e c o g n i z e f a i r l y a c c u r a t e l y t h e r e g i o n s o n t h e s l o p e w h e r e o n e i s l i k e l y t o e n c o u n t e r o n e o r t h e o t h e r g e n u s o f A l c i d a e . S i x s p e c i e s o f a l c i d s b r e e d i n t h e S e v u o k u k c o l o n y , e a c h s p e c i e s a t o n e t i m e o r a n o t h e r i s a s s o c i a t e d w i t h o n e a n o t h e r t o v a r y i n g d e g r e e s . C e p p h u s n e s t s p r e d o m i n a n t l y a m o n g t h e " r u b b l e " a t t h e b a s e o f t h e s l o p e b u t may a l s o b e f o u n d e l s e w h e r e o n t h e s l o p e s w h e r e v e r y l a r g e b o u l d e r s e x i s t a n d i n l e s s e r n u m b e r s o n s c a r p - f a c e s . L u n d a a n d F r a t e r c u l a , p r i m a r i l y b u r r o w - n e s t e r s t h r o u g h o u t m o s t o f t h e i r r a n g e , a r e a l s o e n c o u n t e r e d n e s t i n g a m ong t h e " r u b b l e " a n d c l i f f s . I t i s d i f f i c u l t t o d e s c r i b e i n q u a n t i t a t i v e t e r m s j u s t w h a t a C e p p h u s n e s t i s t h a t m a k e s i t d i f f e r e n t f r o m , f o r e x a m p l e , t h e n e s t o f L u n d a . T h i s d i f f i c u l t y w a s a l s o e n c o u n t e r e d d u r i n g t h e p r e s e n t s t u d y f o r , d e s p i t e t h e g e n e r a l s e g r e g a t i o n o f C y c h l o r r h y n c h u s a n d A e t h i a s p p . o n t h e n e s t i n g s l o p e s , m a n y i n s t a n c e s o f o v e r l a p i n n e s t i n g a m o n g t h e s e s p e c i e s w e r e f o u n d . On n u m e r o u s o c c a s i o n s n e s t s o f c r i s t a t e l l a a n d p u s i l l a , c r i s t a t e l l a a n d p s i t t a c u l a , a n d s o m e t i m e s a l l t h r e e s p e c i e s w e r e f o u n d w i t h i n a b o u t a m e t e r o f e a c h o t h e r a n d i n some i n s t a n c e s w i t h i n a f e w c e n t i m e t e r s o f e a c h o t h e r . I t w a s a p p a r e n t u p o n e x a m i n a t i o n o f t h e p e r i m e t e r s o f t h e n e s t - s i t e e n t r a n c e s o f e a c h s p e c i e s ( t a b l e 7) t h a t t h e g r e a t d i f f e r e n c e s i n b o d y s i z e b e t w e e n p u s i l l a a n d c r i s t a t e l l a o n o n e h a n d , a n d b e t w e e n p u s i l l a a n d p s i t t a c u l a o n t h e o t h e r a c c o u n t e d f o r n e s t - s i t e s e g r e g a t i o n w h e r e p u s i l l a o v e r l a p p e d w i t h t h e o t h e r t w o s p e c i e s . A. p u s i l i a n e s t s i n c r e v i c e s t o o s m a l l f o r e i t h e r p s i t t a c u l a o r c r i s t a t e l l a t o " s q u e e z e " i n t o , w h e r e a s t h e d i f f e r e n c e b e t w e e n a p s i t t a c u l a a n d c r i s t a t e l l a n e s t w a s n o t a s o b v i o u s . I f e e l t h a t t h e o v e r l a p i n n e s t i n g a m o n g t h e s e s p e c i e s , .when i t e x i s t s , o c c u r s i n t h e f o l l o w i n g m a n n e r : p u s i l l a o v e r l a p s c r i s t a t e l l a a n d t o a l e s s e r d e g r e e , p s i t t a c u l a , a n d c r i s t a t e l l a o v e r l a p s p s i t t a c u l a . A. p u s i l l a i s o f t e n e n c o u n t e r e d n e s t i n g i n " t y p i c a l " c r i s t a t e l l a h a b i t a t , b u t i t u t i l i z e s t h e s m a l l e r a n d o b v i o u s l y l e s s n u m e r o u s c r e v i c e s i n t h e L e g e n d f o r T a b l e 7 M e a n m e a s u r e m e n t s o f n e s t e n t r a n c e p e r i m e t e r s , p e r c h t o n e s t e n t r a n c e d i s t a n c e s a n d t i m e e l a p s e d f r o m l a n d i n g o n p e r c h e s t o e n t e r i n g m a n t l e o r n e s t - s i t e s i n P a r a k e e t , C r e s t e d a n d L e a s t a u k l e t s o n S t . L a w r e n c e I s l a n d , 1 9 6 7 . T h e f i r s t n u m b e r i n p a r e n t h e s e s i s t h e s a m p l e s i z e f o l l o w e d b y t h e r a n g e o f v a l u e s . T A B L E 7 S p e c i e s P e r i m e t e r o f N e s t E n t r a n c e (cm) D i s t a n c e f r o m P e r c h t o N e s t E n t r a n c e (m) T i m e E l a p s e d f r o m L a n d i n g o n P e r c h t o E n t e r i n g M a n t l e o r N e s t - s i t e s * ( m i n u t e s ) c. p s i t t a c u l a 38. 4 (16:25.4-48.6) 2.4 (22:0.6-4. 7) 20(11:12-35) A. c r i s t a t e l l a 40. 3 (5:31. 6-48.4) 0.9 (5:0.3-2.1) 3(17:1-6) A. p u s i l l a 23. 9 (7:16.1-28.2) 0.5(8:0.2-1.1) 2(21:0.5-5) . * M e a s u r e m e n t s t a k e n d u r i n g c h i c k - r e a r i n g p e r i o d , a d u l t s c a r r y i n g f o o d t o t h e i r c h i c k s . 57 l a r g e p a r t i c l e s . These smaller c r e v i c e s are u n a v a i l a b l e t o the l a r g e r c r i s t a t e l l a and thus, n e s t i n g segregation i s s t i l l complete. The reverse s i t u a t i o n does not occur, i n other words, c r i s t a t e l l a i s absent i n areas where p a r t i c l e s down to 2.0dcm e x i s t and hence p u s i l l a abounds e x c l u s i v e l y . In the Sevuokuk colony, Cychlorrhynchus appeared to nest e q u a l l y on the t a l u s slope where weakly weathered outcrops appear at the surface i n the form of r i d g e s ( p r i m a r i l y along the brow of the mountain) and where p a r t i a l l y f r a c t u r e d parent rock comes to the surfac e . Cych1orrhynchus was never found n e s t i n g amid rounded boulders, as appears to be the case on the P r i b i l o f Islands (Bent, 1919) , which support the bulk of the Ae t h i a spp. breeding population. However, p u s i l l a and cr i s t a t e l l a , p a r t i c u l a r l y the l a t t e r , were oft e n encountered n e s t i n g i n areas occupied by Cych1orrhyn chu s. What d i f f e r e n t i a t e s between a c r i s t a t e l l a and a p s i t t a c u l a n e s t - s i t e i n areas of overlap posed a problem which I have by no means solved. However, some observations are i n t e r e s t i n g . Bedard (1967) suggested that h y p o t h e t i c a l f a c t o r s of the mi c r o - h a b i t a t may i n f l u e n c e n e s t - s i t e s e l e c t i o n , the h a b i t s of the two Ae t h i a may be e f f e c t e d by the c o n d i t i o n of the subs t r a t e or the d i f f e r e n t i a l use they make of the mantle. These p o s s i b i l i t i e s were considered i n t h i s study and i t w i l l be shown that the l a t t e r may be of p a r t i c u l a r importance. 5 8 F r o m t a b l e 7 we s e e , a s i s t o b e e x p e c t e d b y t h e i r e q u a l b o d y s i z e , t h a t n e s t e n t r a n c e p e r i m e t e r s o f p s i t t a c u l a a n d c r i s t a t e l l a a r e s i m i l a r . R e c o r d i n g s o f n e s t - s i t e t e m p e r a t u r e s o f t h e s e s p e c i e s ( t a b l e s 14 an d 24 and f i g u r e 16) r e v e a l e d no g r o s s d i f f e r e n c e s t h a t m i g h t i n f l u e n c e n e s t - s i t e s e l e c t i o n . A more s u b t l e f a c t o r o r f a c t o r s a p p e a r e d t o o p e r a t e . D i f f e r e n c e s i n b e h a v i o r o f C y c h l o r r h y n c h u s a nd A e t h i a a d u l t s d u r i n g t h e c h i c k - r e a r i n g p e r i o d may b e i m p o r t a n t . On t h e i r p e r c h e s , C y c h l o r r h y n c h u s i s l e t h a r g i c a n d i n a c t i v e c o m p a r e d t o A e t h i a , e v e n t h o u g h t h e f o r m e r i s e q u a l l y a g i l e on r o c k s and c a n s c a l e v e r t i c a l r o c k f a c e s . Upon a l i g h t i n g on i t s p e r c h w h i c h i s u s u a l l y some d i s t a n c e f r o m i t s n e s t - s i t e ( t a b l e 7 ) , C y c h l o r r h y n c h u s i s v e r y s l o w i n a p p r o a c h i n g i t s n e s t . Much t i m e i s s p e n t s i t t i n g on t h e p e r c h and p e e r i n g a r o u n d b e f o r e a t t e m p t i n g t o w a l k o v e r t h e r o c k s t o t h e n e s t . The w a l k f r o m t h e p e r c h t o t h e n e s t i s u s u a l l y i n t e r r u p t e d b y s e v e r a l s t o p s . F i n a l l y , t h e m a n t l e i n w h i c h t h e n e s t i s l o c a t e d i s r e a c h e d , a f i n a l s t o p o c c u r s a nd t h e n t h e a d u l t s l i p s i n t o t h e n e s t . The t i m e i n v o l v e d f r o m l a n d i n g on t h e p e r c h t o e n t e r i n g t h e n e s t may b e up t o 35 m i n u t e s b u t a v e r a g e s 20 m i n u t e s ( t a b l e 7 ) . C r e s t e d and L e a s t a u k l e t s , h o w e v e r , a r e much more a c t i v e on t h e r o c k s , t h e i r p e r c h e s a r e l e s s d i s t a n t f r o m t h e i r n e s t s and a s h o r t t i m e i s i n v o l v e d b e t w e e n l a n d i n g on t h e i r p e r c h e s and e n t e r i n g t h e i r nests (table 7). Weather probably a f f e c t s t h i s time p e r i o d but most of the observations were made simultaneously and are thus considered to be comparable. Every Crested and Least a u k l e t nest examined was entered from below or at an angle s i m i l a r to that of the nest f l o o r , u s u a l l y a d i s t a n c e being t r a v e r s e d i n the mantle before the n e s t - s i t e was reached. Only i n c r i s t a t e l l a nest-type B and p u s i l l a nest type C were the nests entered d i r e c t l y from the outer surface of the mantle; the nests were s t i l l entered from the side or from below. Out of 47 nests of Cychlorrhynchus s t u d i e d on the t a l u s slopes, 39 or 73 percent were entered d i r e c t l y from above, a s i t u a t i o n never encountered w i t h A e t h i a nests. The remaining 17 percent were entered from the s i d e d i r e c t l y from the outer surface of the mantle. Thus, innate n e s t - s i t e preferences may operate w i t h i n these species at the i n d i v i d u a l l e v e l of segregation. B. Egg-laying i n Auklets , a. The seasonal p a t t e r n of egg-laying Egg-laying dates-are a v a i l a b l e - f o r C. p s i t t a c u l a , A. c r i s t a t e l l a and A. p u s i l l a i n 1966 and 1967. The date when each c l u t c h was l a i d i s p l o t t e d i n f i g u r e s 13, 14 and 15. Dates of egg-laying were obtained by d i r e c t observations (the s o l i d squares) and are accurate to w i t h i n about s i x hours; those dates obtained by d i s s e c t i o n of 6 0 L e g e n d f o r F i g u r e 13 E g g - l a y i n g i n P a r a k e e t A u k l e t s o n S e v u o k u k M o u n t a i n , S t . L a w r e n c e I s l a n d . S o l i d s q u a r e s i n d i c a t e p o s i t i v e e g g - l a y i n g d a t e s o b t a i n e d b y d i r e c t o b s e r v a t i o n ; o p e n s q u a r e s i n d i c a t e d a t e s o b t a i n e d f r o m d i s s e c t i o n o f f u l l y -s h e l l e d e g g s i n t h e o v i d u c t . 0 certa in D fu l l y -she l led egg in oviduct 6 1 L e g e n d f o r F i g u r e 14 E g g - l a y i n g i n C r e s t e d A u k l e t s o n S e v u o k u k M o u n t a i n , S t . L a w r e n c e I s l a n d . S o l i d s q u a r e s i n d i c a t e p o s i t i v e e g g - l a y i n g d a t e s o b t a i n e d b y d i r e c t o b s e r v a t i o n ; o p e n s q u a r e s i n d i c a t e d a t e s o b t a i n e d f r o m d i s s e c t i o n o f f u l l y -s h e l l e d e g g s i n t h e o v i d u c t . 6 2 L e g e n d f o r F i g u r e 15 E g g - l a y i n g i n L e a s t A u k l e t s o n S e v u o k u k M o u n t a i n , S t . L a w r e n c e I s l a n d . S o l i d s q u a r e s i n d i c a t e p o s i t i v e e g g - l a y i n g d a t e s o b t a i n e d b y d i r e c t o b s e r v a t i o n ; o p e n s q u a r e s i n d i c a t e d a t e s o b t a i n e d f r o m d i s s e c t i o n o f f u l l y -s h e l l e d e g g s i n t h e o v i d u c t . 63 f u l l y s h e l l e d eggs from o v i d u c t s of females (the open squares) are considered to be accurate to w i t h i n one day. Only those dates where e r r o r was apparently impossible were p l o t t e d i n these f i g u r e s . The same nests were checked again i n 1967 which f a c i l i t a t e d o b t a i n i n g accurate egg-l a y i n g dates, o f t e n d i f f i c u l t when only one egg i s l a i d . Extreme dates f o r the two years i n cr i s t a t e l l a nests s t u d i e d are 30 June (1966) and 14 June (1967), and 14 J u l y (1966) and 3 J u l y (1967); i n p u s i l l a , 24 June (1966) and 12 June (1967), and 5 J u l y (1966) and 4 J u l y (1967). One date i n 1966 f o r p s i t t a c u l a shows 5 J u l y ( f u l l y s h e l l e d egg i n oviduct) and extremes i n 1967 are 21 June and 7 J u l y i n nests st u d i e d . Bedard (personal correspondence) found f u l l y s h e l l e d eggs i n o v i d u c t s of c r i s t a t e l l a i n the Sevuokuk colony on 1 J u l y 1964 and extremes of 29 June to 15 J u l y 1965. In p u s i l l a , he found extremes of 26 June to 9 J u l y 1964 and 29 June to 21 J u l y 1965, the l a t e extreme f o r 1965 may p o s s i b l y be a r e - l a y i n g attempt (see Chapter I I , C). C l u t c h commencement dates f o r these species are few i n the l i t e r a t u r e ; most r e p o r t s are f o r eggs whose stage of incubation i s unknown. In p s i t t a c u l a , Friedmann (1935) reported that F i s h e r c o l l e c t e d seven eggs on Kodiak I s l a n d on 19 June 1884. B a i l e y (1948) found f r e s h eggs on the Diomede Islands on 3 J u l y 1941 and s t a t e d (Bailey, 1925) that although they nest on King I s l a n d they had not yet begun to l a y on 27 June 1921. There are eggs i n the Thayer c o l l e c t i o n taken on Sledge I s l a n d on 22 August 1910 (Gabrielson and L i n c o l n , 1959), where Cade (1952) found a p a i r i n h a b i t i n g a burrow on 9 June 1950, but no egg was present. Bent (1919) gives three dates f o r the "northern Bering Sea" as 20 J u l y , 22 and 26 August. On the P r i b i l o f s , egg dates range from 13 June 1890 to 1 J u l y 1873 and 1 J u l y 1914 (Preble and McAtee, 1923) and 8 June and 7, 16 J u l y (Bent, 1919). On the Commander Islands " f r e s h eggs" have been found on 10 June (Kozlova, 195 7) . B a i l e y (1943) and Brooks (1953) reported egg-l a y i n g i n c r i s t a t e l l a s t a r t e d i n e a r l y June on the Diomedes w h i l e J . J . Burns (personal correspondence) found eggs on 10 June but most commonly around 25 June on L i t t l e Diomede. On King I s l a n d , Burns (personal correspondence) found a f r e s h l y broken c r i s t a t e l l a egg which was near hatching on 19 J u l y 1963. Preble and McAtee (1923) reported the f o l l o w i n g egg dates from the P r i b i l o f I s l a n d s : St. George I s l a n d , 19,. 20 June and 4 J u l y 1873; St. Paul I s l a n d , 10 J u l y 1895; Otter I s l a n d , 20,22 June 1884; Walrus I s l a n d , 16 June 1910. Brooks (1953) found p u s i l l a eggs on L i t t l e Diomede I s l a n d on 25 June 1953 and Bent (1919) gave two egg dates f o r "northern Bering Sea" area as 20 June and 2 6 A u g u s t , a n d i n t h e A l e u t i a n I s l a n d s , o n e e g g d a t e , 1 J u l y . A. p u s i l l a l a y s i t s e g g s u s u a l l y i n J u n e o n t h e P r i b i l o f s w i t h d a t e s f o r t h i s l o c a l i t y r a n g i n g f r o m 24 M a y 1 8 9 0 t o 2 J u l y 1 9 1 4 ( P r e b l e a n d M c A t e e , 1 9 2 3 ) . M.C. T h o m p s o n ( p e r s o n a l c o r r e s p o n d e n c e ) s t a t e d t h a t p u s i l l a w e r e l a y i n g " a n d h a v e b e e n f o r o v e r a w e e k " o n 13 J u n e 1 9 6 6 o n S t . G e o r g e I s l a n d . B e d a r d ( p e r s o n a l c o r r e s p o n d e n c e ) o b s e r v e d a d u l t L e a s t A u k l e t s c a r r y i n g f o o d t o t h e i r c h i c k s o n S t . P a u l I s l a n d o n 2 8 J u n e 1 9 6 7 ; t h i s w o u l d g i v e a p p r o x i m a t e e g g d a t e s o f 2 9 o r 30 M a y b a s e d o n t h e 3 1 d a y i n c u b a t i o n p e r i o d f o r t h i s s p e c i e s o n S t . L a w r e n c e I s l a n d . T a b l e 8 s u m m a r i z e s e g g - l a y i n g i n P a r a k e e t , C r e s t e d a n d L e a s t a u k l e t s o n S t . L a w r e n c e I s l a n d i n 1 9 6 6 a n d 1 9 6 7 . B e d a r d ( 1 9 6 7 ) p r e s e n t e d e s t i m a t e d d a t e s o f h a t c h i n g a n d f l e d g i n g o f c r i s t a t e l l a a n d p u s i l l a i n t h e S e v u o k u k c o l o n y i n 1 9 6 4 , 1 9 6 5 a n d 1 9 6 6 . F r o m my d a t a o n i n c u b a t i o n p e r i o d s i n t h e s e s p e c i e s ( a b o u t 35 d a y s i n c r i s t a t e l l a a n d 3 1 d a y s i n p u s i l l a ) B e d a r d ' s f i g u r e s may b e p o s t -d a t e d t o o b t a i n a n a p p r o x i m a t e p i c t u r e o f e g g - l a y i n g i n 1 9 6 4 a n d 1 9 6 5 ; t h u s a c o m p a r i s o n o v e r f o u r s e a s o n s i s p o s s i b l e , 1 9 6 4 t o 1 9 6 7 . T h e t w o s e a s o n s i n t h i s s t u d y r e p r e s e n t t h e e x t r e m e s , 1 9 6 6 b e i n g t h e l a t e s t a n d 1 9 6 7 t h e e a r l i e s t . O b s e r v a t i o n s o n p s i t t a c u l a c h i c k s i n d i c a t e a s i m i l a r l y l a t e e g g - l a y i n g i n 1 9 6 6 a n d d i r e c t 6 6 L e g e n d f o r T a b l e 8 E g g - l a y i n g i n P a r a k e e t , C r e s t e d , a n d L e a s t a u k l e t s . A n a l y s i s f r o m t w o s e a s o n s o n S t . L a w r e n c e I s l a n d , A l a s k a . T A B L E 8 Y e a r S a m p l e s i z e M e a n d a t e S t a n d a r d d e v i a t i o n R a n g e C. p s i t t a c u l a 1 9 6 6 1 J u l y 5 1 9 6 7 13 J u n e 2 3 . 2 2.0 d a y s 2 1 J u n e - 7 J u l y Y e a r S a m p l e s i z e M e a n d a t e S t a n d a r d d e v i a t i o n R a n g e A. c r i s t a t e l l a 1 9 6 6 20 J u l y 3.4 4 . 1 d a y s 3 0 J u n e - 14 J u l y 1 9 6 7 22 J u n e 2 1 . 8 6.3 d a y s 1 4 J u n e - 3 J u l y Y e a r S a m p l e s i z e M e a n d a t e S t a n d a r d d e v i a t i o n R a n g e A. p u s i l l a 1 9 6 6 3 6 J u l y 1.4 3.1 d a y s 24 J u n e - 5 J u l y 1 9 6 7 2 8 J u n e 1 8 . 0 4.4 d a y s 12 J u n e - 4 J u l y 6 7 observations on egg-laying i n t h i s species showed e a r l y egg-laying i n 1967. I f e e l t h a t there i s a s i g n i f i c a n t b i o l o g i c a l reason f o r t h i s d i f f e r e n t i a l t i m i n g of egg-a l y i n g i n these species i n 1966 and 1967 and w i l l d i s c u s s i t i n Chapter VI. b. The d a i l y p a t t e r n of egg-laying The few data that I have on the time of day when au k l e t s l a y t h e i r eggs suggest that l a y i n g i s concentrated d u r i n g the e a r l y morning hours. N e s t - s i t e s were checked between 0200 and 0800 hr each morning during the egg-l a y i n g p e r i o d . No eggs i n nests s t u d i e d appeared between 0800 and 0200 hr. However, si n c e the m a j o r i t y of n e s t -s i t e s were i n a c c e s s i b l e i t i s p o s s i b l e t h a t some eggs were l a i d d uring the l a t t e r p e r i o d . Considering the c i r c a d i a n rhythm of the a u k l e t s i n t h i s colony (see Bedard, 1967), one might suspect l a y i n g to be concentrated during the e a r l y morning hours (as Drent (1961) and Winn (1950) suggested f o r Cepphus). The f o l l o w i n g observations strengthen t h i s suggestion: At 0235 hr on 25 June 1967 walked along the snow on brow of Sevuokuk Mountain checking f o r a u k l e t eggs l a i d on the snow. Returned by same route at 0305 hr and found one p u s i l l a egg, l a i d between 0235 and 0305 hr. At 0410 hr on 18 June 1967 p u s i l l a nest #16 was v i s i t e d but found to be unoccupied. At 0440 hr I looked i n t o t h i s nest and found an a d u l t w i t h an egg. U s i n g a t e m p e r a t u r e r e c o r d e r p l a c e d i n n e s t s w h e r e t h e f e m a l e s w e r e b a n d e d o n M a n d a r t e I s l a n d , B r i t i s h C o l u m b i a , D r e n t (1961:98) o b t a i n e d t w o o b s e r v a t i o n s s h o w i n g t h a t C e p p h u s l a i d e g g s b e t w e e n 0705 a n d 0730 h r a n d " a l m o s t c e r t a i n l y b e t w e e n 0810 a n d 0910 h r " . C. T h e C l u t c h i n P a r a k e e t , C r e s t e d a n d L e a s t A u k l e t s a . D e s c r i p t i o n o f t h e e g g s . T h e s i n g l e e g g o f C. p s i t t a c u l a i s g e n e r a l l y o v a t e i n s h a p e w i t h a t e n d e n c y i n some t o w a r d e l l i p t i c a l o v a t e f o r m s . T h e e g g i s f i n e l y g r a n u l a t e d , r o u g h a n d w i t h o u t l u s t r e . I t s c o l o r i s d u l l w h i t e w i t h a v e r y s u b t l e b l u i s h t i n g e ; h o w e v e r , n o n e w a s f o u n d t o b e " d e c i d e d l y b l u i s h , a b o u t t h e c o l o r o f h e r o n ' s e g g s " ( B e n t , 1919:118). T h e s i n g l e e g g s o f A. c r i s t a t e l l a a n d A. p u s i l l a a r e d u l l w h i t e a n d w i t h o u t l u s t r e b u t d o n o t s h o w t h e b l u i s h t i n g e o r f e e l a s r o u g h a s t h o s e o f p s i t t a c u l a . E a c h s p e c i e s ' e g g s o f t e n b e c o m e s t a i n e d f r o m m o i s t e a r t h o n t h e n e s t f l o o r a s i n c u b a t i o n p r o g r e s s e s . C r e s t e d a n d L e a s t a u k l e t e g g s v a r y i n s h a p e f r o m o v a t e t o p o i n t e d o v a t e . T a b l e 9 g i v e s d i m e n s i o n s o f P a r a k e e t A u k l e t e g g s a n d t a b l e 10 g i v e s t h o s e o f C r e s t e d a n d L e a s t o n S t . L a w r e n c e I s l a n d ; c o m p a r a t i v e m e a s u r e m e n t s f r o m t h e l i t e r a t u r e a r e a l s o g i v e n . I t i s a p p a r e n t t h a t p s i t t a c u l a 6 9 L e g e n d f o r T a b l e 9 D i m e n s i o n s o f P a r a k e e t A u k l e t e g g s . T A B L E 9 No. o f E x t r e m e s M e a n L o c a l i t y M e a s u r e m e n t s (mm) (mm) S o u r c e B e r i n g S e a a r e a 3 3 5 8 . 0 x 3 3 . 5 5 4 . 3 x 3 7 . 3 B e n t ( 1 9 1 9 ) 5 7.5 x 4 0 . 0. 5 1 . 5 x 3 7 . 0 5 2 . 5 x 3 3 . 0 A s i a n S e a c o a s t ? 5 1 . 5 t o 5 8 . 0 l o n g ? K o z l o v a ( 1 9 5 7 ) 3 3 . 0 t o 4 0 . 0 w i d e S t . L a w r e n c e i s l a n d 1 8 5 8 . 7 x 3 7 . 2 5 3 . 3 x 3 7 . 3 T h i s s t u d y 5 3 . 0 x 3 9 . 5  5 0 . 0 x 3 9 . 5 5 1 . 4 x 3 3 . 4 70 L e g e n d f o r T a b l e 10 D i m e n s i o n s o f C r e s t e d a n d L e a s t a u k l e t e g g s . TABLE 10 No. of Extremes Mean Source L o c a l i t y Measurements (mm) (mm) CRESTED AUKLET Bering Sea 30 60. 0 x 41.0 54. 2 X 37. 9 Bent (1919) area 59.0 x 42.5 50. 0 x 38.5 55. 0 x 32.5 Asian Seacoast ? 5 0 to 60 long ? Kozlova (1957) 32.5 to 42.5 wide St. Lawrence 65 58.3 x 38.4 56. 8 X 37. 2 This study I s l a n d 53.4 x 38.9 50. 0 x 36.1 51.6 x 31.8 LEAST AUKLET Bering Sea 57 43. 0 x 28.5 39. 5 X 28. 5 Bent (1919) area 40. 0 x 33.5 33.5 x 29.0 40.0 x 27.0 Asian Seacoast p 33.5 to 43.0 long •> Kozlova (1957) 27.0 to 33.5 wide St. Lawrence 126 44.5 x 27.0 39. 8 X 28. 3 This .study I s l a n d 42. 8 x 32.9 35. 8 x 28.2 39.5 x 26.5 and c r i s t a t e l l a eggs are i n d i s t i n g u i s h a b l e from each other based on s i z e , however, p u s i l l a eggs are r e a d i l y i d e n t i f i e d without observing the adul t on the nest. Tables 11 and 12 record changes i n weight of some a l c i d eggs during i n c u b a t i o n and these egg-weights expressed as percentages of a d u l t body-weights, r e s p e c t i v e l y . The egg and ad u l t weights of A l c a , U r i a , Cepphus and F r a t e r c u l a a r c t i c a i n t a b l e 11 are from Johnson (1944); the eggs weighed by Johnson i r r e g a r d l e s s of t h e i r stage i n in c u b a t i o n , have been entered under the "fresh-egg" column f o r our purposes. I t may be seen from t a b l e 12 t h a t the weight of the egg i n pr o p o r t i o n t o the body weight of the adult v a r i e s among these a l c i d s , ranging from 9o7 percent i n F. c o r n i c u l a t a to 19.0 percent i n p u s i l l a f o r "fresh eggs". This i s i n agreement w i t h the general trend of v a r i a t i o n found w i t h i n each f a m i l y of b i r d s , t h a t i s , f o r smaller species to have p r o p o r t i o n a t e l y l a r g e r eggs (Heinroth, 1922). Lack (1967) showed that c l u t c h s i z e and the r e l a t i v e s i z e of eggs i n waterfowl are i n v e r s e l y r e l a t e d . He st a t e d (p. 126) t h a t " i t i s reasonable to suggest t h a t the c l u t c h s i z e and the s i z e of eggs have been evolved i n r e l a t i o n t o the average a v a i l a b i l i t y of food f o r the female around the time of l a y i n g " . Lack a l s o suggests (p. 126) "the female has l i m i t e d food reserves which can be used t o form e i t h e r a few la r g e 72 L e g e n d f o r T a b l e 1 1 W e i g h t s o f f r e s h a n d p i p p e d e g g s i n e i g h t s p e c i e s o f a l c i d s . D a t a f o r A l c a t o r d a , U r i a a a l g e , C e p p h u s g r y l l e , a n d F r a t e r c u l a a r c t i c a a r e f r o m J o h n s o n ( 1 9 4 0 ) . D a t a f o r F_. c o r n i c u l a t a f r o m S e a l y , u n p u b l i s h e d d a t a . T h e v a l u e o u t s i d e t h e p a r e n t h e s e s i s t h e m e a n v a l u e ; t h e f i r s t n u m b e r i n s i d e t h e p a r e n t h e s e s i s t h e s a m p l e s i z e , t h e l a s t t w o n u m b e r s a r e t h e e x t r e m e s . A d u l t b o d y - w e i g h t s i n c l u d e d f o r c o m p a r i s o n . TABLE 11 Species Fresh Eggs* Pipped Eggs * Adul t s A l c a t o r d a Ur i a aalge Cepphus g r y l l e Cy ch1orrhynchu s  ps i t t a c u l a A e t h i a c r i s t a t e l l a A e t h i a p u s i l l a F r a t e r c u l a a r c t i c a F. c o r n i c u l a t a 85.4 (38:73.5-100) 103.4 (15:83-117) 49. 2 (23:42-65) 37.5 (3 :36. 6-39. 1) 40.5 (10:37.6-42.8) 17.5 (14:14.2-19.8) 55. 9 (30:54.5-73. 2) 57.1 (2 :56. 1-58. 1) 34. 8 (4:28.4-34.5) 32.8 (3 :31. 2-33.6) 13.7 (7:12.3-14.9) 686 (7:608-740) 964.7 (89:815-1150) 419 (69: ) 280.6 (17:224. 7-316.2) 286.6 (192:25 0.5-324.6) 92. 0 (125 :70. 2-113.1) 476.1 (29:407-542) 587.1 (15:499.6-690.9) * Weights i n grams 73 L e g e n d f o r T a b l e 12 E g g - w e i g h t i n r e l a t i o n t o b o d y - w e i g h t i n some a l c i d s ( w e i g h t s i n g r a m s ) . E g g a n d b o d y - w e i g h t s o f A l c a t o r d a , U r i a a a l g e , C e p p h u s g r y l l e , a n d F r a t e r c u l a a r c t i c a a r e f r o m J o h n s o n ( 1 9 4 0 ) , t h e w e i g h t s o f F_. c o r n i c u l a t a a r e f r o m S e a l y , u n p u b l i s h e d d a t a . J o h n s o n ' s e g g - w e i g h t s a r e c o n s i d e r e d t o b e f r e s h e g g s . T A B L E 12 S p e c i e s F r e s h E g g s P i p p e d E g g s A l c a t o r d a 1 2 . 4 % -- •-U r i a a a l g e 1 0 . 1% — •-• C e p p h u s g r y l l e 1 1 . 1% — •-C y c h l o r r h y n c h u s p s i t t a c u l a 1 3 . 3% 1 2 . 4 % A e t h i a c r i s t a t e l l a 1 4 . 2% 1 1 . 5 % A e t h i a p u s i l l a 1 9 . 0% 1 4 . 6 % F r a t e r c u l a a r c t i c a 1 1 . 1% '-- •-F. c o r n i c u l a t a 9. 1% — • — 74 eggs or more smaller ones". Examination of the shape and c o l o r a t i o n of a l e i d eggs r e l a t i v e to t h e i r n e s t i n g h a b i t s r e v e a l s c e r t a i n apparent adaptive f e a t u r e s . The egg-form v a r i e s . f r o m e l l i p t i c a l i n p u f f i n s , ovate i n a u k l e t s t o p y r i f o r m i n murres. B e l o p o l s k i i (1961) and Tuck (1961) demonstrated the adaptive s i g n i f i c a n c e of pyriform-shaped eggs of murres which are l a i d on open, rocky ledges. Here a d i s l o d g e d egg r o t a t e s on i t s a x i s i n a manner governed by i t s s t a t e of i n c u b a t i o n (Tuck, 1961) and t h e r e f o r e c u r t a i l s the chance of r o l l i n g o f f the smooth surface. P u f f i n and auklet eggs, which are u s u a l l y l a i d i n burrows and c r e v i c e s , r e s p e c t i v e l y , are i n l e s s danger of r o l l i n g . The c o l o r of auk eggs a l s o v a r i e s apparently according to the type of n e s t - s i t e u t i l i z e d by the p a r t i c u l a r species. Those which nest i n open or semi-open s i t u a t i o n s have c r y p t i c a l l y c o l o r e d eggs, e.g., the e x t i n c t Pinguinus, A l c a , Ur i a spp., Cepphus, and those n e s t i n g i n concealed s i t u a t i o n s , e.g., Plautus, Cychlorrhynchus, A e t h i a , are d u l l white or b l u i s h . B e l o p o l s k i i (1961) s t a t e d t h a t f a i n t markings on some p u f f i n eggs, which are l a i d i n burrows, are s u p e r f i c i a l . An exception are the spotted eggs of Endomychura and Synthliboramphus, which are a l s o l a i d i n burrows. This may i n d i c a t e these l a t t e r two species acquired the burrow-nesting h a b i t l a t e i n the h i s t o r y of the A l c i d a e , however, Dawson (1920:14) s t a t e d that the submerged markings on the eggs of these species " i n d i c a t e a considerable a n t i q u i t y , but there i s no evidence of a c t u a l l o s s of c o l o r through t r o g l o d y t i c h a b i t , unless, p o s s i b l y i n the l i g h t e r ground shades of S. antiquus". Tschanz (1959) demonstrated that the c a p a c i t y to l e a r n the i n d i v i d u a l c h a r a c t e r i s t i c s of an egg i s w e l l developed i n Common Murres. He found t h a t they have a strong i n h i b i t i o n against r e t r i e v i n g an egg of another b i r d , unless i t c l o s e l y resembles t h e i r own. b. C l u t c h s i z e Cychlorrhynchus, A. c r i s t a t e l l a and A. p u s i l l a l a y one egg to a c l u t c h . There i s one record i n the l i t e r a t u r e of Cychlorrhynchus and A e t h i a l a y i n g "two unmarked eggs (Storer, 1945:455) but t h i s i s apparently i n e r r o r f o r he e a r l i e r s t a t e d (p. 453) that "In shape of the hind limb and p e l v i s and the s i n g l e white, ovate egg the Auklets (Ptychoramphus, Cychlorrhynchus and Aethia) form a very homogeneous group". One-egg c l u t c h e s i s the general r u l e i n the A l c i d a e , except Cepphus (Wynne-Edwards, 1955) where two eggs are most common (Drent, 1965), Endomychura (Bent, 1919) and Synthliboramphus (Drent and Guiguet, 1961). One-egg c l u t c h e s have been recorded i n Cepphus (Drent, 1965; Thoresen and Booth, 1958; Winn, 1950) as w e l l as three-egg c l u t c h e s (Winri, 1950), but the l a t t e r i s considered by Drent (1965) to be probably the work of two females or p o s s i b l y replacement l a y i n g . Rare instances of two-egg c l u t c h e s i n p u f f i n s (F. a r c t i c a ) have been reported (Kaftanowskii, 1951) and A l c a (Fisher and Lockley, 1954). Storer (1945) described Cerorhinca, F r a t e r c u l a and Lunda as l a y i n g two eggs which are u s u a l l y f a i n t l y marked. According to Bent (1919), Dawson and Bowles (1909), Kozlova (195 7) and Richardson (1961) , Cerorhinca lays only one egg, however, "Apparently a second egg may be l a i d i f the f i r s t i s destroyed (Richardson, 1961:463). Lunda a l s o l a y s only one egg (Bent, 1919; Kozlova, 1957; Drent and Guiguet, 1961; Drent, et a_l, 1964) . c. Replacement of l o s t or destroyed eggs I t i s known th a t most b i r d s are capable of l a y i n g successive c l u t c h e s , provided the f i r s t c l u t c h i s l o s t soon a f t e r l a y i n g (Sleptsov, 1948). The f a m i l y A l c i d a e i s no exception f o r repeat c l u t c h e s have been reported f o r most auks s t u d i e d . Despite adequate sampling and examination of o v a r i e s , Bedard (1967) observed only one apparent instance (A. p u s i l l a i n 1966) of repeat l a y i n g i n Cychlorrhynchus and A e t h i a . In 1967 I observed an i r r e f u t a b l e case of r e n e s t i n g i n Cychlorrhynchus and two p o s s i b l e instances of r e n e s t i n g i n each of A. c r i s t a t e l l a and A. p u s i l l a . 77 On 26 J u n e 1 9 6 7 a n a d u l t P a r a k e e t A u k l e t w a s c a p t u r e d b y h a n d i n a n e m p t y n e s t - s i t e o n S e v u o k u k M o u n t a i n a n d b a n d e d n o . 5 1 4 - 3 8 1 0 9 ; a f u l l y s h e l l e d e g g i n i t s o v i d u c t c o u l d b e f e l t . Oh 27 J u n e t h e e g g w a s p r e s e n t a n d o n 29 J u n e i t w a s a c c i d e n t a l l y b r o k e n b y me a n d r e m o v e d . On 4 A u g u s t t h i s n e s t w a s r e v i s i t e d a n d t h e same f e m a l e w a s f o u n d i n c u b a t i n g a n e g g ; i t h a t c h e d o n 1 8 A u g u s t b u t t h e c h i c k w a s k i l l e d b y a m i c r o t i n e r o d e n t b y 19 A u g u s t . I d o n o t k n o w i f t h e s a m e m a l e w a s i n v o l v e d i n t h i s r e n e s t i n g ; h o w e v e r , t h e m a i n t e n a n c e o f t h e p a i r - b o n d t h r o u g h o u t t h e b r e e d i n g s e a s o n a n d p r o b a b l y o v e r a n u m b e r o f y e a r s w o u l d s u g g e s t t h a t t h e s a m e m a l e w a s i n v o l v e d . C o n s i d e r i n g t h e h a t c h i n g d a t e o f t h e s e c o n d e g g , 1 8 A u g u s t , a n d t h e 3 5 - d a y i n c u b a t i o n p e r i o d o f C y c h l o r r h y n c h u s o n S t . L a w r e n c e I s l a n d , t h e s e c o n d e g g m u s t h a v e b e e n l a i d a b o u t 14 J u l y o r a b o u t 16 d a y s a f t e r t h e f i r s t o n e w a s d e s t r o y e d . On 17 J u n e i n p u s i l l a n e s t #5, a n e g g w a s b e i n g i n c u b a t e d i n a b o u t t w o cm o f w a t e r . On 14 J u l y t h e o r i g i n a l e g g w a s s t i l l p r e s e n t i n t h e n e s t b u t p u s h e d a s i d e , a n d a n a d u l t w a s i n c u b a t i n g a n o t h e r e g g . T h i s e g g w a s b e i n g i n c u b a t e d o n 20 J u l y b u t w a s a b a n d o n e d - b y 25 J u l y ; i t w a s a d d l e d . N e i t h e r a d u l t f r o m n e s t #5 w a s m a r k e d m a k i n g i t i m p o s s i b l e t o b e s u r e r e n e s t i n g o c c u r r e d . On 17 J u l y a p u s i l i a n e s t c o n t a i n i n g t w o e g g s , o n e b e i n g i n c u b a t e d i n a b o u t o n e cm o f w a t e r a n d t h e o t h e r ' , b r o k e n a n d p u s h e d a s i d e , w a s f o u n d . T h e e g g b e i n g i n c u b a t e d s h o w e d n o 78 e m b r y o n a l d e v e l o p m e n t a n d t h e " o r i g i n a l " e g g w a s a d d l e d . T h e a d u l t f e m a l e w a s c o l l e c t e d a n d i t s o v a r i e s w e r e d i s s e c t e d a n d e x a m i n e d ; o n l y o n e p o s t o v u l a t e d f o l l i c l e w a s e v i d e n t , a s e c o n d o r p r e v i o u s l y o v u l a t e d f o l l i c l e i f p r e s e n t , w a s n o t d i s c e r n a b l e . On 26 J u n e t h e e g g i n c r i s t a t e l l a n e s t #36 w a s l a i d ; o n 20 J u l y i t w a s f o u n d t h a t e g g #36 w a s p u s h e d a s i d e a n d a s e c o n d e g g w a s b e i n g i n c u b a t e d . N e i t h e r a d u l t i n n e s t #36 w a s b a n d e d . D e s e r t i o n o c c u r r e d a b o u t 25 J u l y a n d n e i t h e r e g g s h o w e d e m b r y o n a l d e v e l o p m e n t . R u n - o f f w a t e r w a s d e e m e d t h e c a u s e o f t h e f i r s t e g g b e i n g a b a n d o n e d . A s e c o n d p o s s i b l e r e n e s t i n g a t t e m p t i n c r i s t a t e l l a w a s f o u n d o n 5 A u g u s t o n t h e w e s t s l o p e o f S e v u o k u k M o u n t a i n ; t w o e g g s w e r e p r e s e n t , o n e w a s p u s h e d a s i d e a n d t h e o t h e r w a s b e i n g i n c u b a t e d . T h e e g g b e i n g i n c u b a t e d c o n t a i n e d a w e 1 1 - d e v e l o p e d e m b r y o b u t t h e " f i r s t " e g g w a s a d d l e d . I t a p p e a r s , a l t h o u g h t h e e v i d e n c e r e g a r d i n g c r i s t a t e l l a a n d p u s i l l a i s c i r c u m s t a n t i a l , t h a t r e n e s t i n g may o c c u r i n t h e s e a u k l e t s , p a r t i c u l a r l y i n a n e a r l y s e a s o n . T h e f a c t t h a t r e n e s t i n g i n p s i t t a c u l a n e s t #6 i s i r r e f u t a b l e m a y s u p p o r t t h e p o s s i b i l i t y o f i t s o c c u r r e n c e i n A e t h i a . T h e a d a p t i v e s i g n i f i c a n c e o f r e n e s t i n g i n a u k l e t s i n a n e a r l y s e a s o n l i k e 1 9 6 7 i s a p p a r e n t w h e n s n o w - m e l t i s c o n s i d e r e d . E v i d e n t a l l y t h e c a u s e o f e g g 79 r e j e c t i o n in the above p u s i l l a and one c r i s t a t e l l a nests was submergence in run-off water which flows down the slope in small streamlets among the rocks when snow melts. As t h i s brow-snow continued to melt i t produced continuous run-off which no doubt found.its way to numerous auklet nests. It i s probable that auklets can successfully hatch an egg that has been temporarily submerged in water, as has been found in Brant (Barry, 1962), but continued submergence in cold water would probably k i l l an embryo. The temperature inside a pus i l i a egg which was being incubated in water on 17 July 1967 (the second p u s i l l a nest mentioned above) was 11.2°C compared to about 38°C in eggs under "normal" incubation. In a. la t e r season the brow-snow melts shortly after egg-laying commences throughout the colony and auklet eggs are exposed to minimal run-off water. Thus, loss of eggs in an early season may be compensated for by abandoning the f i r s t egg and laying a second. Drent (1965) found in C. columba that no replacements were noted i f only one of a two-clutch was l o s t , but i f the entire clutch was l o s t a repeat clutch appeared in approximately 13 days in about h a l f of the cases. For C. g r y l l e Winn (1950) recorded two repeat clutches in 15 days or less and Uspenski (1958) recorded one 18-day i n t e r v a l . For C. columba Thoresen and Booth (1958) estimated two cases of 18 days. Alca, Ur ia spp. 80 and F r a t e r c u l a a r c t i c a are a l s o known to renest i f t h e i r eggs are removed e a r l y i n incubation (Paluden, 1947; Uspenski, 1958; Tschanz,. 1959; Kartaschew, 1960) . D. Incubation i n Parakeet, Crested and Least Auklets a. Incubation periods i n a u k l e t s Assuming normal, undisturbed i n c u b a t i o n , the average time i n t e r v a l between l a y i n g an egg and emergence of the young b i r d represents the i n c u b a t i o n p e r i o d (Heinroth, 1922). However, according to Tucker (1943) and Swanberg (1950), a b i r d can s i t on an egg without heating i t , thus, f o r p r a c t i c a l purposes a s p e c i e s ' incubation p e r i o d may be d e f i n e d as the i n t e r v a l between l a y i n g the l a s t egg of a c l u t c h and hatching of the l a s t egg (assuming that a l l eggs hatch). Observations on a u k l e t s on St. Lawrence I s l a n d showed that a d u l t s c o n t i n u a l l y sat on the one-egg c l u t c h e s immediately a f t e r they were l a i d but these observations are not accompanied by temperature data t o show e x a c t l y when' the eggs were f i r s t heated. For purposes of t h i s study i t i s assumed that eggs i n undisturbed nests are heated from the time they were l a i d u n t i l they hatched. Drent (1965) emphasized the importance of s t a t i n g c l e a r l y the obvious i n t e r v a l s between l a y i n g and hatching. The 24-hour photoperiod which p r e v a i l s throughout most of the breeding season on t h i s I sland enabled l a y i n g dates obtained by d i r e c t observation (as opposed to those obtained L e g e n d f o r T a b l e 13 P e r i o d f r o m l a y i n g e g g u n t i l t h e c h i c k i s f r e e o f t h e s h e l l i n C. p s i t t a c u l a , A. c r i s t a t e l l a , a n d A. p u s i l l a . D a t a f r o m 1 9 6 6 a n d 1 9 6 7 c o m b i n e d . T A B L E 13 C. p s i t t a c u l a 35 d a y s 3 3 6 d a y s 1 N u m b e r o f c a s e s 4 M e a n 3 5 . 2 d a y s c r i s t a t e l l a A. p u s i l l a 3 4 d a y s 2 28 d a y s 1 3 6 d a y s 2 29 d a y s 6 3 7 d a y s 2 32 d a y s 4 33 d a y s 1 34 d a y s 1 3 6 d a y s 2 6 15 3 5 . 6 d a y s 3 1 . . 2 d a y s 8 2 b y d i s s e c t i o n o f e g g - l a y i n g f e m a l e s ) t o b e a c c u r a t e t o w i t h i n a b o u t s i x h o u r s . N e s t - s i t e s w e r e c h e c k e d b e t w e e n 0 2 0 0 a n d 0 8 0 0 h r e a c h m o r n i n g d u r i n g t h e e g g - l a y i n g p e r i o d , e g g s p r e s e n t o n t h e s e c o n d v i s i t o f t h e m o r n i n g w e r e c o u n t e d a s b e i n g l a i d o n t h a t d a y . T h e h a t c h i n g d a t e o f e a c h c h i c k i s a c c u r a t e t o t h e n e a r e s t d a y , t h e n e s t s b e i n g c h e c k e d i n t h e same s e q u e n c e e a c h d a y b e t w e e n 1 0 0 0 a n d 1 4 0 0 h r ; t h e m a x i m u m e r r o r i n t h e d e t e r m i n a t i o n o f t h e i n c u b a t i o n p e r i o d s o f t h e s e a u k l e t s i s t h u s a b o u t 3 0 h o u r s b u t i n m o s t c a s e s i s p r o b a b l y l e s s t h a n 24 h o u r s . D a t a f r o m f o u r n e s t s o f p s i t t a c u l a i n 1 9 6 7 , s i x n e s t s o f c r i s t a t e l l a a n d 15 n e s t s o f p u s i l l a i n 1 9 6 6 a n d 1 9 6 7 a r e s h o w n i n t a b l e 1 3 . My h a t c h i n g d a t a may b e s u m m a r i z e d a s f o l l o w s : t h e i n t e r v a l b e t w e e n t h e o c c u r r e n c e o f t h e f i r s t c r a c k s o n t h e e g g a n d e m e r g e n c e o f t h e c h i c k f r o m t h e s h e l l w a s v a r i a b l e . T h i s t i m e i n t e r v a l i n f o u r e g g s o f p s i t t a c u l a i n 1 9 6 7 w a s 2 t o 4 d a y s (mean, 3.0 d a y s ) , i n 8 e g g s o f c r i s t a t e l l a i n b o t h s e a s o n s w a s 2 t o 6 d a y s (mean, 3.3 d a y s ) , a n d i n 27 e g g s o f p u s i l l a i n b o t h s e a s o n s w a s 1 t o 7 d a y s ( m e a n , 3.2 d a y s ) . A b o u t t w o d a y s p r i o r t o h a t c h i n g i n p s i t t a c u l a a n d c r i s t a t e l l a a n d o n e d a y i n p u s i l i a a d e f i n i t e h o l e ( t h e " p i p p e d " c o n d i t i o n ) a p p e a r e d o n t h e e g g . T h e v o i c e o f t h e u n h a t c h e d c h i c k w a s a h o a r s e c h e e p i n g w h i c h , a c c o r d i n g t o D r e n t ( 1 9 6 1 ) , i s n o d o u b t i m p o r t a n t i n p r e p a r i n g t h e p a r e n t s f o r f e e d i n g , e t c . 83 t o c o m e . He a l s o s t a t e d t h a t t h e c h i c k s ' v o i c e s may f u n c t i o n d i r e c t l y i n e n s u r i n g c o n t i n u o u s i n c u b a t i o n , s i n c e t h e p i p p e d e g g m u s t n o t d r y o u t , a n d f u r t h e r p o s s i b l y p l a y s a r o l e a l o n g w i t h t a c t i l e s t i m u l i i n a l t e r i n g t h e s t a n c e o f t h e a d u l t s o n t h e e g g s . T h e r e a r e n o i n c u b a t i o n p e r i o d s o f C. p s i t t a c u l a , A. c r i s t a t e l l a a n d A. p u s i l l a i n t h e l i t e r a t u r e . I n c u b a t i o n p e r i o d s o f o t h e r p l a n k t o n - f e e d i n g a l c i d s a r e 24 d a y s f o r P l a u t u s ( F a b e r _ i n U s p e n s k i , 1 9 5 8 ) a n d " a t l e a s t 37 d a y s " i n P t y c h o r a m p h u s ( T h o r e s e n , 1 9 6 4 ) . b . I n c u b a t i o n t e m p e r a t u r e s i n P a r a k e e t , C r e s t e d a n d L e a s t a u k l e t s F r o m 20 J u l y t o 12 S e p t e m b e r 1 9 6 6 a m b i e n t t e m p e r a t u r e s i n t h e S e v u o k u k c o l o n y a n d a c o n t i n u o u s r e c o r d i n g o f a i r t e m p e r a t u r e s i n a c r i s t a t e l l a n e s t - s i t e w e r e o b t a i n e d . I n 1 9 6 7 a m b i e n t t e m p e r a t u r e s w e r e r e c o r d e d f r o m 6 J u n e t o 7 S e p t e m b e r a n d s p o r a d i c c o n t i n u o u s r e c o r d i n g s o n t h e f l o o r o f a p u s i l l a n e s t w e r e o b t a i n e d . A f t e r 15 J u l y 1 9 6 7 a t e l e t h e r m o m e t e r w a s a v a i l a b l e a n d w a s u s e d i n t h e r m o r e g u l a t o r y s t u d i e s ( r e p o r t e d i n C h a p t e r I I I ) . S e v e r a l " s p o t " m e a s u r e m e n t s o f n e s t - s i t e a i r t e m p e r a t u r e s i n e a c h s p e c i e s w e r e o b t a i n e d d u r i n g t h e t h e r m o r e g u l a t i o n s t u d i e s a n d a r e s h o w n i n t a b l e 2 4 . 1. N e s t t e m p e r a t u r e s S i n c e i n c l e m e n t w e a t h e r , p a r t i c u l a r l y c h i l l i n g 84 w i n d s , i s a common f e a t u r e o f S t . L a w r e n c e I s l a n d ' s s u m mer c l i m a t e , i t w a s d e e m e d i m p o r t a n t t o s e e w h a t s t a b i l i z i n g a n d s h e l t e r i n g e f f e c t s i f a n y w e r e a f f o r d e d b y t h e n e s t m i c r o - e n v i r o n m e n t , a mong t h e i n t e r s t i c e s o f t h e r o c k s . F i g u r e 16 c o m p a r e s t h e a i r t e m p e r a t u r e i n a c r i s t a t e l l a n e s t - s i t e t o t h e a m b i e n t t e m p e r a t u r e s f r o m a b o u t 20 J u l y t o 13 S e p t e m b e r 1 9 6 6 ( t a b l e 3) I t i s s e e n t h a t t e m p e r a t u r e s i n t h i s n e s t - s i t e w e r e f a i r l y s t a b l e d e s p i t e h i g h e r o r l o w e r a m b i e n t t e m p e r a t u r e s . T h i s n e s t -s i t e n e v e r r e a c h e d t h e g e n e r a l m i n i m u m , a f a c t p o s s i b l y e x p l a i n e d b y t h e s l o w c o o l i n g o f t h e s u r r o u n d i n g r o c k ( D r e n t , 1 9 6 1 ) . T h e n e s t t e m p e r a t u r e w a s g r e a t e r t h a n t h e a m b i e n t t e m p e r a t u r e t h r o u g h o u t m o s t o f t h e p e r i o d o f m e a s u r e m e n t . T h i s i s m o s t l i k e l y d u e t o t h e c h i l l i n g e f f e c t o f t h e o c e a n o n t h e a i r a b o v e t h e s l o p e ( T r e w a r t h a , 1 9 5 4 ) , i n t h i s c a s e a t t h e 8m c o n t o u r . T h e c h i l l i n g e f f e c t s o f t h i s a i r i n s i d e t h e n e s t s i s p o s s i b l y g r e a t b u t w a s n o t m e a s u r e d . T a b l e 14 s h o w s s p o r a d i c t e m p e r a t u r e r e c o r d i n g s i n o n e p u s i l l a n e s t a t t h e 55m c o n t o u r o n t h e n o r t h e a s t s l o p e o f S e v u o k u k M o u n t a i n a n d o n e p u s i l i a n e s t o n t h e w e s t s l o p e o f t h e M o u n t a i n a t t h e 100m c o n t o u r . P r o b e s w e r e p l a c e d o n t h e n e s t f l o o r , p r i o r t o e g g - l a y i n g i n t h e k n o w n n e s t - s i t e o n t h e w e s t s l o p e a n d a f t e r t h e e g g h a d b e e n l a i d i n t h e n o r t h e a s t s l o p e n e s t - s i t e , i n a m a n n e r w h e r e b y t h e p r o b e w a s n o t i n f l u e n c e d b y t h e a d u l t . T h e h i g h e r n e s t f l o o r t e m p e r a t u r e s o b t a i n e d d u r i n g t h e 85 L e g e n d f o r F i g u r e 16 M e a n m a x i m u m a n d m i n i m u m a i r t e m p e r a t u r e s i n a n e s t -s i t e o f A. c r i s t a t e l l a d u r i n g t h e l a t t e r h a l f o f t h e b r e e d i n g s e a s o n , 1 9 6 6 , S t . L a w r e n c e I s l a n d . M e a n m a x i m u m a n d m i n i m u m a m b i e n t t e m p e r a t u r e s f o r t h e s a m e p e r i o d a r e a l s o g i v e n . T e m p e r a t u r e s r e c o r d e d a t t h e 8m c o n t o u r o n t h e s l o p e . I 8-14 15-21 22-28 29-31 1-7 8-14 15-21 22-28 29-31 1-7 8-14 15-21 July | August I September nest temperature @ @ air temperature L e g e n d f o r T a b l e 14 T e m p e r a t u r e s i n s i d e t h e S t . L a w r e n c e I s l a n d , A l a s k a , i n ° C . n e s t - s i t e o f A e t h i a p u s i l l a , 1 9 6 7 . T e m p e r a t u r e s m e a s u r e d T A B L E 14 M e a n M e a n P e r i o d M a x i m u m M i n i m u m . x T e m p e r a t u r e J u n e 2-8 * 1 4 . 7 1 0 . 0 1 2 . 4 9 - 1 1 * 1 6 . 7 1 1 . 7 1 4 . 2 J u l y 2 1 - 2 8 * * 8.3 7.2 7.7 A u g u s t 1 1 - 1 9 * * 5.2 6.0 5.6 * One n e s t - s i t e o n w e s t s l o p e o f S e v u o k u k M o u n t a i n * * One n e s t - s i t e o n n o r t h e a s t s l o p e o f S e v u o k u k M o u n t a i n 87 two periods i n June (June 2-8, 9-11) may be accounted f o r by the f a c t t h i s nest was lo c a t e d on the west slope of the Mountain where d i r e c t s u n l i g h t , which i s more pre v a l e n t i n t h i s month, would apparently be f e l t . The J u l y and August recordings are from the northeast slope which i s g e n e r a l l y shaded. The lower nest f l o o r temperatures obtained d u r i n g the l a t t e r readings as compared to ambient temperatures from the same slope may be due to the damp s o i l on the nest f l o o r . I t appears t h a t a u k l e t s ' nest-temperature regimes have the f o l l o w i n g s i g n i f i c a n c e : (1) the eggs and chi c k s are subjected to low but s t a b l e nest micro-environmental temperatures d e s p i t e wide ranges of ambient temperatures and c h i l l i n g winds, (2) the n e s t - s i t e temperatures do not reach the minimum ambient temperatures, and (3) n e s t - s i t e temperatures are greater than the a i r temperatures above the slope p o s s i b l y due to the absence of the c h i l l i n g f a c t o r from the ocean. 2. Brood patches and brood patch temperatures Two brood patches are present on C. p s i t t a c u l a , A. C r i s t a t e l l a and A. p u s i l l a ; each i s l o c a t e d on the f l a n k s under each wing. The average brood patch .dimensions i n f i v e p s i t t a c u l a was 44 x 27mm, i n four c r i s t a t e l l a 43 x 27mm, and s i x p u s i l l a 25 x 15mm. According to B a i l e y (1952) and Kozlova (1957) brood patches are present i n a l l a l c i d s . T h e v a r y i n g n u m b e r a n d l o c a t i o n o f t h e s e b r o o d p a t c h e s i n a l c i d s h a s b e e n s t u d i e d i n s e v e r a l s p e c i e s ( s e e P a y n e , 1 9 6 6 ) . T h e a b s e n c e o f a b r o o d p a t c h o r p a t c h e s i n P t y c h o r a m p h u s a l e u t i c a a n d i t s a p p a r e n t s i g n i f i c a n c e h a s b e e n d i s c u s s e d b y P a y n e ( 1 9 6 6 ) . I f e e l t h a t o b s e r v a t i o n s g a i n e d i n t h e p r e s e n t s t u d y d o n o t f u l l y s u p p o r t P a y n e ' s a r g u m e n t s . P a y n e s t a t e d ( p . 2 0 9 ) t h a t " T h e a b s e n c e o f a b r o o d p a t c h i n C a s s i n A u k l e t s may b e r e l a t e d t o t h e s m a l l s i z e o f t h e s e s e a - b i r d s . T h e b o d y s u r f a c e - v o l u m e r a t i o i s l a r g e r i n s m a l l b i r d s , a n d t h e p r e s e n c e o f a r e l a t i v e l y l a r g e u n f e a t h e r e d a r e a o n t h e b o d y m i g h t b r i n g o n e x c e s s l o s s o f h e a t t o t h e c o l d o c e a n " . H e l a t e r p o i n t e d o u t t h a t o n l y t h o s e a l c i d s r e p o r t e d h a v i n g b r o o d p a t c h e s , e x c e p t f o r P l a u t u s , a r e l a r g e r t h a n P t y c h o r amphu s. T h e p r e s e n c e o f b r o o d p a t c h e s i n A e t h i a p u s i l l a , w h i c h w e i g h s a b o u t 9 0 g c o m p a r e d t o a b o u t 1 7 2 g f o r P t y c h o r a m phu s ( T h o r e s e n , 1 9 6 4 ) , a p p e a r s t o s u p p o r t t h i s o b j e c t i o n t o P a y n e , a t l e a s t r e g a r d i n g t h i s p o i n t . I t i s a l s o i n t e r e s t i n g t o n o t e t h a t t h e t e m p e r a t u r e o f t h e B e r i n g S e a i n summer i n t h e v i c i n i t y o f S t . L a w r e n c e I s l a n d v a r i e s a r o u n d 0 - 1 0 ° C ( G o o d m a n , e t a l , 1 9 4 2 ; t h i s s t u d y ) w h i l e t h e o c e a n t e m p e r a t u r e n e a r S o u t h F a r a l l o n I s l a n d , C a l i f o r n i a ( w h e r e P a y n e ' s w o r k w a s d o n e ) , i s a b o u t 1 1 - 1 5 ° C i n t h e summer ( S v e r d r u p , e t a l , 1 9 4 2 ) . T h e a v e r a g e b o d y t e m p e r a t u r e o f s i x P t y c h o r a m p h u s w a s 4 1 . 5 ° C a n d t h e t e m p e r a t u r e o f t h e s k i n 8 9 b e n e a t h t h e i r w i n g s w a s 3 9 . 7 ° C ( P a y n e , 1 9 6 6 ) . S i m i l a r m e a s u r e m e n t s o f 13 p u s i l l a w e r e 4 0 . 7 ° C a n d 3 8 . 0 ° C ( t a b l e 1 5 ) , r e s p e c t i v e l y , o n S t . L a w r e n c e I s l a n d . D r e n t ( 1 9 6 5 ) , w o r k i n g w i t h C e p p h u s , o b t a i n e d d a t a o n t e m p e r a t u r e a t t h e i n t e r f a c e b e t w e e n t h e u p p e r e g g s u r f a c e a n d b r o o d p a t c h ( t e r m e d " i n c u b a t i o n t e m p e r a t u r e " f o l l o w i n g F a r n e r , 1 9 5 8 ) w h i c h s h o w e d t h a t t h e d e f i n i t i v e l e v e l o f t h i s t e m p e r a t u r e i s n o t r e a c h e d u n t i l t h e s e c o n d e g g h a s b e e n l a i d , o r s o o n t h e r e a f t e r . B y u s i n g a t e l e t h e r m o m e t e r a n d p r o b e s t a p e d t o t h e s h e l l o f t h e e g g i n s u c h a w a y a s t o b e i n c o n t a c t w i t h t h e a d u l t ' s b r o o d p a t c h , h e w a s a b l e t o s e c u r e t h e s e t e m p e r a t u r e r e a d i n g s . I n t h e p r e s e n t s t u d y o n l y " s p o t " m e a s u r e m e n t s o f b r o o d p a t c h t e m p e r a t u r e s i n a d u l t a u k l e t s n e a r t h e e n d o f i n c u b a t i o n w e r e o b t a i n e d . T h e r e s u l t s , p r e s e n t e d w i t h b o d y t e m p e r a t u r e s f o r c o m p a r i s o n i n t a b l e 1 5 , . c a n n o t b e a c c u r a t e l y c o m p a r e d t o D r e n t ' s d a t a f o r h i s b r o o d p a t c h t e m p e r a t u r e s w e r e m e a s u r e d d i r e c t l y f r o m a d u l t s s i t t i n g o n a n d p r e s u m a b l y a p p l y i n g h e a t t o t h e i r e g g s . My r e a d i n g s m e a s u r e d w i t h i n 15 m i n u t e s a f t e r r e m o v i n g t h e a u k l e t s f r o m t h e i r n e s t s , i n v o l v e d e x c i t e d , " h a n d l e d " b i r d s w h e r e b i a s i s i m m i n e n t ( U d v a r d y , 1 9 5 3 ) . H o w e l l a n d B a r t h o l o m e w ( 1 9 6 1 ) , h o w e v e r , u s e d t h i s l a t t e r m e t h o d w i t h a p p a r e n t s u c c e s s i n D i o m e d e a . D r e n t ( 1 9 6 1 ) s u m m a r i z e d t h e r o l e o f i n c u b a t i o n p a t c h e s i n b i r d s , e m p h a s i z i n g t h e i r s p e c i a l m o d i f i c a t i o n L e g e n d f o r T a b l e 15 T e m p e r a t u r e s o f t h e f u l l y d e v e l o p e d b r o o d p a t c h c o m p a r e d t o t h e b o d y t e m p e r a t u r e s i n a u k l e t s . B o d y t e m p e r a t u r e s a r e e s o p h a g e a l a n d m e a s u r e d i n ° C . T A B L E 15 D e s c r i p t i o n S a m p l e S i z e M e a n C. p s i t t a c u l a i n c u b a t i n g e g g C. p s i t t a c u l a b r o o d p a t c h A. c r i s t a t e l l a i n c u b a t i n g e g g A. c r i s t a t e l l a b r o o d p a t c h A. p u s i l l a i n c u b a t i n g e g g P u s i l l a b r o o d p a t c h 9 12 2 3 13 12 4 0 . 4 3 6 . 9 4 0 . 1 3 8 . 1 4 0 . 7 3 8 . 0 9 1 t o a p p l y t e m p e r a t u r e s t o e g g - s u r f a c e s t h a t i s a l m o s t a s h i g h a s t h e p a r e n t ' s b o d y t e m p e r a t u r e . A n e x a m i n a t i o n o f t a b l e 15 r e v e a l s t h a t t h e b r o o d p a t c h t e m p e r a t u r e o f p s i t t a c u l a i s a b o u t 4 ° C l e s s t h a n t h e b o d y t e m p e r a t u r e a n d a b o u t 1-2°C l o w e r i n c r i s t a t e l l a a n d p u s i l l a . T a b l e 16 s u m m a r i z e s a v a i l a b l e i n f o r m a t i o n o n b r o o d p a t c h a n d b o d y t e m p e r a t u r e s i n a l c i d s . C o n s i d e r i n g t a b l e s 15 a n d 1 6 , i t i s s e e n t h a t a u k l e t b o d y t e m p e r a t u r e s o n S t . L a w r e n c e I s l a n d a r e c o m p a r a b l e t o e a c h o t h e r a n d t o w i t h i n o n e o r t w o d e g r e e s o f b o d y t e m p e r a t u r e s o f a l c i d s i n o t h e r l o c a l i t i e s . T h e b r o o d p a t c h t e m p e r a t u r e s o f a u k l e t s a r e l o w e r t h a n t h o s e o f o t h e r a l c i d s e x c e p t f o r C e p p h u s  g r y l l e . T h e t h r e e r e a d i n g s f o r F_. c o r n i c u l a t a w e r e o b t a i n e d i n a n i d e n t i c a l m a n n e r t o t h a t o f t h e a u k l e t s , b u t t h e t e c h n i q u e s i n v o l v e d w i t h t h e o t h e r s p e c i e s , e x c e p t C. c o l u m b a , a r e u n k n o w n ; i t i s t h u s u n w i s e t o b a s e c o n c l u s i o n s o n t h e s e d i f f e r e n c e s . c . I n c u b a t i o n r h y t h m i n P a r a k e e t , C r e s t e d a n d L e a s t a u k l e t s T h e f e w a v a i l a b l e r e p o r t s i n t h e l i t e r a t u r e i n d i c a t e t h a t b o t h s e x e s i n P a r a k e e t , C r e s t e d a n d L e a s t a u k l e t s i n c u b a t e ( B e d a r d , 1 9 6 7 , f o r a l l t h r e e s p e c i e s ; B e n t , 1 9 1 9 , a n d G a b r i e l s o n a n d L i n c o l n , 1 9 5 9 , f o r c r i s t a t e l l a ; G a b r i e l s o n a n d L i n c o l n , 1 9 5 9 , f o r p u s i l l a ) , b u t n o t e s o n a t t e n t i v e n e s s , i n c u b a t i o n s h i f t s a n d t h e t i m e w h e n s t e a d y i n c u b a t i o n a c t u a l l y s e t s i n a r e l a c k i n g . E x c e p t 92 L e g e n d f o r T a b l e 16 T e m p e r a t u r e s o f t h e f u l l y d e v e l o p e d b r o o d p a t c h c o m p a r e d t o b o d y t e m p e r a t u r e i n s ome a l c i d s . T e m p e r a t u r e s a r e o m e a s u r e d i n C. TABLE 16 Species Brood Patch Temperature Body Temperature Author i t y Ur i a lomv i a 41. 0 39.0 Kartaschew (1960) U. lomvia 41.5 41.5 Uspenski (1958) Cepphus g r y l l e 35 - 37 — Kartaschew (1960) C. columba 40. 6 39.4 Drent (1965); r e c t a l * F r a t e r c u l a a r c t i c a 42. 3 42. 3 Lockley (1953); r e c t a l * F. c o r n i c u l a t a * * 40. 1 38. 0 Sealy (unpublished data) ; esophageal* Method of o b t a i n i n g body temperature Three i n sample f o r B e d a r d , t h e k n o w l e d g e t h a t b o t h s e x e s i n t h e s e a u k l e t s i n c u b a t e a p p e a r s t o b e u n q u a l i f i e d , p o s s i b l y b a s e d o n t h e p r e t e x t t h a t b o t h s e x e s i n m a n y o t h e r a l c i d s a r e k n o w n t o s h a r e i n c u b a t i o n d u t i e s . T h e p r e s e n c e o f b r o o d p a t c h e s o n m a l e a u k l e t s i s i n d i c a t i v e o f t h e i r p a r t i c i p a t i o n i n i n c u b a t i o n , h o w e v e r , t h e s e x e s a r e n o t s e x u a l l y d i m o r p h i c w i t h r e s p e c t t o e x t e r n a l m o r p h o l o g y , a n d i t i s n e c e s s a r y t o c a p t u r e a n d d i s s e c t i n c u b a t i n g a d u l t s b e f o r e a s e t i n c u b a t i o n p a t t e r n , i f o n e c o u l d b e d e t e r m i n e d , e x i s t s . T h e c o n c e a l e d n a t u r e o f t h e n e s t - s i t e s p r e c l u d e d d i r e c t o b s e r v a t i o n s o f i n c u b a t i o n a n d a t e m p e r a t u r e r e c o r d e r w a s n o t a v a i l a b l e t o o v e r c o m e t h i s d i f f i c u l t y , o r t o d e t e r m i n e t h e e x a c t o n s e t o f i n c u b a t i o n . F i v e i n c u b a t i n g a u k l e t s , t h r e e c r i s t a t e l l a a n d t w o p u s i l i a , w e r e c o l l e c t e d d u r i n g b o t h t h e e v e n i n g a n d m i d - d a y p e r i o d s i n t h e i n c u b a t i o n s t a g e ; d i s s e c t i o n r e v e a l e d m a l e s a n d f e m a l e s i n c u b a t e d u r i n g e i t h e r p e r i o d . T h e s a m p l e i s t o o s m a l l f o r a p a t t e r n , i f o n e e x i s t s , c o n c e r n i n g t h e r o l e o f t h e s e x e s i n i n c u b a t i o n t o b e d i s c e r n e d . I n t h e l i t e r a t u r e , s o - c a l l e d e v e n i n g a n d m o r n i n g s h i f t s i n i n c u b a t i o n h a v e b e e n d e s c r i b e d , t h e c h a n g i n g o f t h e s e s h i f t s p r o v i d i n g a s p e c t a c u l a r b i r d d i s p l a y ( d e s c r i b e d i n B e n t , 1 9 1 9 ; G a b r i e l s o n a n d L i n c o l n , 1 9 5 9 ) . A c c o r d i n g t o B e d a r d ( p e r s o n a l c o r r e s p o n d e n c e ) t h e c h a n g e o f . s h i f t s i s n o t t h e c a u s e o f t h e s p e c t a c u l a r d i s p l a y o b s e r v e d b y t h e f o r m e r a u t h o r s ; h e f e e l s t h a t . t h i s c h a n g e i s r e l a t e d t o t h e i r c i r c a d i a n r h y t h m a n d i s i n d e p e n d e n t o f i n c u b a t i n g p a r t n e r s . 94 CHAPTER I I I . The Chick Stage A discussion of the manner of r a i s i n g young within the auk family i s given by Drent (1965). He stated (p. 134) that auks r a i s e t h e i r young "by three d r a s t i c a l l y d i f f e r e n t methods". The f i r s t group includes Endomychura and Synth1iboramphus whose chicks scramble to sea within a couple of days after hatching. In the second group, consisting of the open-nesters, Uria spp., and the semi-open-nester, Alca, the chicks are fed at the n e s t - s i t e for about 20 days before they go to sea. In the l a s t group the chicks are fed at the ne s t - s i t e s u n t i l they are f u l l y developed or about one month of age before f l u t t e r i n g out to sea to assume an independent existence. Making up t h i s t h i r d group are many nocturnal and diurnal burrow-nesters, e.g., Cepphus, Ptychoramphus, Cerorhinca, Fratercula, Lunda, and the crevice and c l i f f - n e s t e r s , e.g., Plautus, Cychlorrhynchus, Aethia. A. The Nestling Period in Auklets The n e s t l i n g periods of C. p s i t t a c u l a , A. cr i s t a t e l l a and A. p u s i l l a have not been previously determined. Bent (1919) described young Crested Auklets as remaining in the nesting cavity u n t i l they are f u l l y developed and able to f l y . Similar observations on t h i s 95 s p e c i e s w e r e m a d e b y K o z l o v a ( 1 9 5 7 ) . T a b l e 17 s u m m a r i z e s t h e n e s t l i n g p e r i o d s o f p s i t t a c u l a , c r i s t a t e l l a a n d p u s i l l a o n S t . L a w r e n c e I s l a n d . I n e a c h c a s e t h e c h i c k w a s l a s t s e e n i n t h e n e s t - s i t e b e t w e e n 1 3 0 0 a n d 1 8 0 0 h r o n t h e p r e v i o u s a f t e r n o o n , a n d a s i s s h o w n " l a t e r m o s t o f t h e c h i c k s d e p a r t e d f o r s e a i n t h e e a r l y m o r n i n g ( o f t h e d a y g i v e n i n t a b l e 1 7 ) . I t b e c o m e s a p p a r e n t u p o n e x a m i n a t i o n o f t a b l e 1 7 t h a t t h e a v e r a g e t i m e s p e n t i n t h e n e s t b y t h e c h i c k s may b e l o n g e r o r s h o r t e r f r o m o n e y e a r t o t h e n e x t . B e f o r e c o n s i d e r i n g p o s s i b l e c a u s e s o f s h o r t e n i n g t h e n e s t l i n g p e r i o d i n d i f f e r e n t y e a r s i t i s n e c e s s a r y t o e x a m i n e t h e g r o w t h o f c h i c k s a n d t h e f a c t o r s c o n t r o l l i n g g r o w t h a n d i t s r a t e ; t h i s w i l l b e d o n e l a t e r i n t h i s c h a p t e r a n d s u m m a r i z e d i n C h a p t e r V I . T h e r e i s c o n s i d e r a b l e e v i d e n c e t o s h o w t h a t t h e r e i s a s h o r t e r n e s t l i n g p e r i o d i n a r c t i c - b r e e d i n g b i r d s a s c o m p a r e d t o t e m p e r a t e o r t r o p i c - b r e e d e r s ( A r m s t r o n g , 1 9 5 4 ; I r v i n g , 1 9 6 0 ; O a k e s o n , 1 9 5 4 ; a n d o t h e r s ) . I n t h e A l c i d a e o n l y P t y c h o r amphu s may b e c o m p a r e d t o t h e B e r i n g S e a a u k l e t s r e g a r d i n g t h e d u r a t i o n o f t h e i r n e s t l i n g p e r i o d s . P t y c h o r amphu s, w h o s e s i z e i s i n t e r m e d i a t e b e t w e e n t h e s m a l l e r A. p u s i l l a a n d l a r g e r A. c r i s t a t e l l a a n d C. p s i t t a c u l a , h a s a n e s t l i n g p e r i o d o f 4 1 t o 5 0 d a y s i n s o u t h e r n O r e g o n a n d n o r t h e r n C a l i f o r n i a ( T h o r e s e n , 1 9 6 4 ) . 9 6 L e g e n d f o r T a b l e 17 N e s t l i n g p e r i o d s o f P a r a k e e t , C r e s t e d a n d L e a s t a u k l e t s o n S t . L a w r e n c e I s l a n d , A l a s k a , i n 1 9 6 6 a n d 1 9 6 7 . TABLE 17 N e s t l i n g P e r i o d 1966 1967 1966 and 1967 Parakeet Auklet 34 days — 1 — 35 days — 3 — 36 days — 1 — 37 days — 1 — MEAN Crested 35.3 days Auklet — — 30 days 2 — 2 32 days 1 — 1 33 days — 1 1 34 days 3 6 9 35 days 1 2 3 MEAN 32.0 days Least 34.1 days Auklet 33.5 days 25 days 1 — 1 27 days 1 — 1 28 days 3 1 4 29 days 3 2 5 30 days 1 4 5 31 days 2 1 3 32 days 1 — 1 MEAN 28.9 days 29.6 days 29.2 days 97 B. Feeding Habits of Auklets a. Prey species In the manner c h a r a c t e r i s t i c of plankton-feeding (as d i s t i n c t from f i s h - f e e d i n g ) a l c i d s , Parakeet, Crested and Least a u k l e t parents c a r r y food to t h e i r c h i c k s i n a neck-pouch, a s p e c i a l d i v e r t i c u l u m of the b u c c a l c a v i t y (Bedard, 1967). The parents c a r r y i n g food t o t h e i r c h i c k s are e a s i l y recognized by the swollen c o n d i t i o n of the neck. The food h a b i t s of these a u k l e t s were e x t e n s i v e l y s t u d i e d on St. Lawrence I s l a n d by Bedard (1967) i n the summers of 1964, 1965 and 1966 and a f u n c t i o n a l i n t e r p r e t a t i o n of the e x i s t i n g feeding p a t t e r n s was presented. In 1966 I a s s i s t e d Bedard i n c o l l e c t i n g b i r d s on t h e i r f eeding grounds from May t o J u l y ; during the l a t t e r p a r t of J u l y , 1967, food samples were obtained from adu l t s on the n e s t i n g slope during the mid-day feeding p e r i o d , approximately two hours between 1400 and 1600 hr. Inclement weather immediately p r i o r to hatching i n 1967 prevented c o l l e c t i n g b i r d s on t h e i r feeding grounds at sea at t h i s time. Sampling techniques, a n a l y t i c a l techniques, sources of e r r o r , e t c , have been discussed by Bedard (1967:33-50), and w i l l not be repeated. In t h i s s e c t i o n Bedard 1s f i n d i n g s regarding the food items of a d u l t a u k l e t s and t h a t which i s brought to the c h i c k s , t h a t i s , samples c o l l e c t e d from a d u l t s f o r a g i n g at sea 98 d u r i n g the pre-egg and incubation stages and parents on the n e s t i n g slope d u r i n g the c h i c k - r e a r i n g p e r i o d are summarized. According t o Bedard, p r e l i m i n a r y examination of food samples revealed no d i f f e r e n c e between the d i e t of a d u l t b i r d s themselves and the d i e t they s e l e c t e d f o r t h e i r c h i c k s . The apparent s i g n i f i c a n c e of the d i e t changes that occurs throughout the breeding season i n A e t h i a spp. but not i n Cychlorrhynchus w i l l be discussed i n Chapter VI. Figure 17 ( f i g u r e 20 of Bedard, 1967) presents prey items and t h e i r r e l a t i v e importance i n the e a r l y summer d i e t of A. c r i s t a t e l l a and A. p u s i l l a (food i n t h e i r g u l l e t s ) . Figure 18 ( f i g u r e 21 of Bedard, 1967) summarizes prey items and t h e i r r e l a t i v e importance i n the food brought to the c h i c k s during August and September (food i n neck-pouch) f o r A e t h i a spp. and Cychlorrhynchus. Bedard sorted the food items which appear i n these f i g u r e s according to type and s i z e . The s i z e was determined on o v e r a l l l e n g t h ( t i p of rostrum or cephalothorax to t i p of t e l s o n ) , e x c l u d i n g long appendages such as the antennae of some gammarids. The s i z e c a t e g o r i e s were as f o l l o w s : Size I (0.1 to 7.0mm); Si z e I I (7.1 to 15.0mm); Size I I I (15.1mm and over). The f o l l o w i n g summary of the seasonal feeding patterns of Cychlorrhynchus and Aeth i a spp. are from Bedard (1967:155-156): 99 Legend f o r F i g u r e 17 R e l a t i v e importance (in volume) of v a r i o u s prey-items of v a r i o u s s i z e c a t e g o r i e s i n the e a r l y summer d i e t of A e t h i a p u s i l l a and A e t h i a c r i s t a t e l l a (food i n g u l l e t s ) . Samples from 1964, 1965 and 1966 and both sexes combined. From, Bedard (1967:46, f i g u r e 20). Code f o r s i z e c a t e g o r i e s d i s c u s s e d i n t e x t of the present t h e s i s . i n m Size categor ies 100 L e g e n d f o r F i g u r e 18 R e l a t i v e i m p o r t a n c e ( i n v o l u m e ) o f v a r i o u s p r e y t y p e s o f v a r i o u s s i z e c a t e g o r i e s i n t h e f o o d b r o u g h t t o t h e c h i c k d u r i n g A u g u s t a n d S e p t e m b e r ( f o o d i n n e c k - p o u c h e s ) . S a m p l e s f r o m 1 9 6 4 , 1 9 6 5 a n d 1 9 6 6 a n d b o t h s e x e s c o m b i n e d . F r o m , B e d a r d ( 1 9 6 7 : 4 7 , f i g u r e 2 1 ) . C o d e f o r s i z e c a t e g o r i e s a s i n f i g u r e 1 7 . Relative importance (% of total volume) Calanus  f inmarchicus Calanus  cristatus Eucalanus  bungii H Y P E R I I D E A • E U P H A U S I A C E A • MYSIDACEA C A R I D E A 1 — ro o o o o cn O o O o > CD —«-a 101 (1) The two species of A e t h i a e x h i b i t r a t h e r s i m i l a r p a tterns of dependence upon the food source; both show during e a r l y summer a d i v e r s i f i e d d i e t c o n s i s t i n g of mysids, h y p e r i i d s , gammarids, e t c . , but r e s t r i c t themselves l a r g e l y t o one p r i n c i p a l prey d u r i n g the c h i c k - r e a r i n g p e r i o d . Then, A. p u s i l l a eats mostly Calanus finmarchicus while, A. c r i s t a t e l l a eats Thysanoessa spp. (2) This sharp r e v e r s a l to monophagy duri n g the c h i c k - r e a r i n g p e r i o d apparently r e f l e c t s a sudden increase i n the a v a i l a b i l i t y of these prey items i n the surrounding waters. A v a i l a b l e evidence i n d i c a t e s that the food c a r r i e d to the chick does not d i f f e r from the food used by a d u l t b i r d s themselves. In a l l years, hatching c o i n c i d e d c l o s e l y w i t h the appearance of these prey items i n the environment and i t i s b e l i e v e d t h a t the breeding season has been adjusted to t h e i r c y c l i c a l abundance. (3) Cychlorrhynchus occupies a s l i g h t l y higher p o s i t i o n i n the t r o p h i c pyramid. This i s i n d i c a t e d by i t s e a t i n g a higher p r o p o r t i o n of carnivorous zooplankton (such as h y p e r i i d s , f i s h , pteropods, cephalopods, etc.) than e i t h e r species of A e t h i a . (4) Although sampling i s l e s s adequate i n the case of Cychlorrhynchus, there i s no sig n that t h i s species r e v e r t s to one p r i n c i p a l type of prey during the p e r i o d of r e a r i n g t h e i r c h i c k s . They seem r a t h e r to show a 1 0 2 p r e f e r e n c e f o r n u m e r o u s t y p e s o f p r e y d u r i n g t h a t p e r i o d . C. G r o w t h o f C h i c k s G r o w t h o f b o d y w e i g h t a n d c e r t a i n b o d y p a r t s w a s s t u d i e d i n t h e C r e s t e d a n d L e a s t a u k l e t s i n b o t h s e a s o n s a n d i n P a r a k e e t A u k l e t s i n 1 9 6 7 . T h e r e a r e n o p r e v i o u s s t u d i e s o f g r o w t h i n t h e s e s p e c i e s . T a b l e s 1 8 , 19 a n d 2 0 , a n d f i g u r e s 1 9 a n d 20 s u m m a r i z e b o d y w e i g h t r e c o r d s f o r e a c h s p e c i e s o b t a i n e d d u r i n g t h e s t u d y . T h e n u m b e r o f c h i c k s o f k n o w n h a t c h i n g d a t e i n v. a c c e s s i b l e n e s t s d i d n o t r e m a i n c o n s t a n t d u r i n g t h e s t u d y d u e i n p a r t t o m i c r o t i n e p r e d a t i o n ; a l s o , m a n y c h i c k s , p a r t i c u l a r l y c r i s t a t e l l a , b e c a m e i m p o s s i b l e t o r e a c h i n t h e n e s t ^ - s i t e s a s t h e y b e c a m e o l d e r a n d m o r e a w a r e o f d a n g e r f o r t h e y o f t e n r e t r e a t e d t o t h e i n n e r r e c e s s e s o f t h e r o c k c r e v i c e s o u t o f r e a c h . T a b l e 2 1 c o m p a r e s w e i g h t s a n d m e a s u r e m e n t s o f t h e o u t e r p r i m a r y , t a r s u s , c u l m e n a n d f i r s t r e c t r i x i n y o u n g a u k l e t s a t h a t c h i n g ( d a y 0) a n d p o i n t o f d e p a r t u r e w i t h t h o s e o f t h e a d u l t s . I n e a c h c a s e t h e b o d y w e i g h t o f y o u n g a t t h e t i m e o f d e p a r t u r e r e p r e s e n t s my l a s t r e c o r d f o r t h a t c h i c k - i t h a d d e p a r t e d b y t h e t i m e o f my l a s t n e s t - c h e c k t h e f o l l o w i n g d a y . When y o u n g a u k l e t s l e a v e t h e n e s t t o t a k e u p a p p a r e n t l y i n d e p e n d e n t e x i s t e n c e s , t h e y h a v e a t t a i n e d , o n t h e a v e r a g e , 7 9 . 3 % , 7 9 . 6 % a n d 8 7 . 5 % o f t h e a d u l t b o d y w e i g h t s i n p s i t t a c u l a , c r i s t a t e l l a Legend f o r Table 18 Growth i n Parakeet A u k l e t s , St. Lawrence I s l a n d , 1967. TABLE 18 Age i n Mean Range Days Sample S i z e (g) (g) 0 4 28. 1 25.6-34.4 1 4 32. 9 27.5-38.9 2 4 39.5 31.9-45.5 3 5 45. 2 37.9-51.2 4 6 56.5 48.2-62.3 5 6 63.0 52.4-71.2 6 6 73. 7 61.7-79.8 7 5 87.4 68.4-114.3 8 6 94.8 _ 73.3-108.7 9 6 100.3 84.7-118.9 10 6 108. 2 93.2-141.2 11 6 117. 7 94.4-149.2 12 6 127. 0 111.1-153.3 13 6 140. 6 110.4-169.4 14 6 154.8 134.5-182.6 15 5 166.5 152.2-195.8 16 6 175. 2 153.3-220.6 17 5 184. 7 169.2-214.1 18 5 191.3 171.4-217.1 19 6 191. 7 180.1-214.2 20 6 195.4 183.4-212.9 21 6 203. 2 182.7-234.7 22 6 207.5 185.1-250.9 23 5 206. 8 187.4-259.4 24 6 215. 7 169.7-263.4 25 4 222. 0 191.1-271. 7 26 4 249.0 207.2-276.6 27 5 237.9 205.5-265.4 28 5 249.1 230.1-278.9 29 4 251. 0 232.7-280.9 30 4 238. 7 225.1-251.2 31 4 238.4 217.7-256.7 32 4 219.2 203.6-244.4 33 4 227. 3 205.0-248.6 34 5 236. 1 206.1-264.4 35 2 218. 1 194.1-242.1 36 1 241.1 37 1 235. 6 1 0 4 L e g e n d f o r T a b l e 19 G r o w t h i n t h e C r e s t e d A u k l e t s , S t . L a w r e n c e I s l a n d . D a t a f o r 1 9 6 6 a n d 1 9 6 7 c o m b i n e d . TABLE 19 Age i n Mean Range Days Sample S i z e (g) (g) 0 13 29.5 24.1-34. .1 1 12 33. 9 30.1-35.8 2 10 39.6 35.3-43.0 3 12 48. 6 40.6-56.4 4 14 55.1 48.4-61.0 5 13 63. 9 57.6-74.2 6 15 74. 2 54.9-83.4 7 14 83.4 70.8-94.5 8 15 93.6 83.3-102.4 9 14 107.6 91.6-113.5 10 12 120. 0 105.6-135.6 11 12 133. 8 117.1-142.3 12 12 148.4 139.8-160.0 13 13 159. 7 149.4-175.1 14 12 172.4 157.8-185.6 15 14 182. 0 175.4-210.6 16 12 186. 8 166.2-198.7 17 13 194. 2 159.5-217.1 18 11 207. 2 155.6-238.8 19 12 214.4 170.8-237.1 20 12 221. 3 186.2-253.6 21 13 238. 2 196.6-271.8 22 11 250.0 207.6-290.6 23 12 240.8 215.7-274.1 24 12 256.9 221.7-279.7 25 10 249. 3 211.2-268.7 26 12 252. 3 222.8-287.1 27 12 260. 2 203.7-294.3 28 11 254.4 214.3-295.6 29 11 254. 3 209.3-284.1 30 9 252. 1 238.8-281.6 31 9 240.6 225.3-262.5 32 7 233. 5 217.3-248.4 33 7 218. 9 203.6-241.7 34 3 221.1 212.2-235.6 35 1 215.6 1 0 5 L e g e n d f o r T a b l e 20 G r o w t h i n L e a s t A u k l e t s o n S t . L a w r e n c e I s l a n d , A l a s k a . D a t a f o r 1 9 6 6 a n d 1 9 6 7 p r e s e n t e d s e p a r a t e l y . TABLE 20 1966 1967 Age i n Sample Mean Range Age i n Sample Mean Range Days S i z e (g) (q) Days S i z e (q) (q) 0 17 12. 3 9.5-14.6 0 15 12.4 9.9-15.9 1 18 15.4 10.9-18.1 1 16 14.5 10.9-17.9 2 17 18. 1 14.8-21.1 2 14 17.5 11.2-20.8 3 14 21. 9 14.2-27.9 3 14 21. 8 16.1-27.7 4 15 26. 1 14.9-32.6 4 13 26.4 22.0-27.7 5 17 29. 2 16.2-36.5 5 11 29. 1 23.7-33.2 6 17 34.4 18.5-47.3 6 11 35. 0 29.3-45.2 7 13 39. 3 27.6-56.2 7 10 40. 0 31.7-51.9 8 12 41. 2 26.7-56.2 8 10 46.1 35.8-55.2 9 15 45. 9 26.4-59.3 9 7 50.3 39. 1-57. 1 10 14 51. 8 30.2-76.4 10 8 57.2 47.6-62.9 11 13 54. 8 31.1-69.7 11 6 58. 9 51.7-67.8 12 14 59. 3 38.9-75.1 12 10 62. 7 53.9-71.3 13 14 65. 8 40.6-79.5 13 9 67. 7 57.4-76.6 14 .14 68.0 43.2-79.6 14 10 71. 7 63.0-78.9 15 13 73. 0 55.6-84.0 15 9 74. 7 69.2-82.2 16 12 74.1 52.7-92.9 16 8 79. 0 69.8-88.9 17 13 82. 6 64.4-101.4 17 7 81.4 73.1-86.4 18 13 ' 81. 3 62.7-97.2 18 6 84. 8 77.2-89.6 19 14 85.5 68.1-109.8 19 6 86,5 77,2-91,3 20 13 89.8 72.5-109.8 20 8 85.3 79.5=94.1 21 12 89.0 71.7-114.2 21 8 87. 0 79.4-95.6 22 13 89.8 72.5-109.8 22 7 85. 2 77.4-92.6 23 13 90.0 64.0-108.2 23 7 84.4 79.2-91.2 24 12 92. 3 66.3-111.4 24 8 84..2 79.5-96.9 25 10 94. 7 78.9-110.2 25 7 86.8 74.4-95.2 26 11 89.3 73.8-106.8 26 8 85. 2 73.9-101.1 27 9 88. 9 64.1-105.5 27 7 82. 6 73.8-91.1 28 7 87. 2 74.5-102.6 28 6 78. 0 70.8-84.3 29 4 89.6 82.2-97.6 29 5 78.4 70.5-83.1 30 3 88.1 84.8-91.7 30 1 81. 2 31 1 88. 2 1 0 6 L e g e n d f o r T a b l e 2 1 B o d y - w e i g h t s a n d m e a s u r e m e n t s o f y o u n g a u k l e t s a t h a t c h i n g a n d a t t i m e o f s e a - g o i n g , S t . L a w r e n c e I s l a n d , A l a s k a . W e i g h t s a n d m e a s u r e m e n t s a r e f o r 1 9 6 6 a n d 1 9 6 7 c o m b i n e d . T h e n u m b e r o u t s i d e t h e p a r e n t h e s e s i s t h e mean v a l u e ; t h e n u m b e r i n s i d e t h e p a r e n t h e s e s i s t h e s a m p l e s i z e f o l l o w e d b y t h e e x t r e m e v a l u e s . A d u l t b o d y - w e i g h t s a n d m e a s u r e m e n t s a r e i n c l u d e d f o r c o m p a r i s o n . TABLE 21 A t H a t c h i n g A t Sea-going A d u l t s _C. p s i t t a c u l a w e i g h t (g) o u t e r p r i m a r y (mm) t a r s u s (mm) culmen (mm) #1 r e c t r i x (mm) A. c r i s t a t e l l a w e i g h t (g) o u t e r p r i m a r y (mm) t a r s u s (mm) culmen (mm) #1 r e c t r i x A. p u s i l l a w e i g h t (g) o u t e r p r i m a r y (mm) t a r s u s (mm) culmen (mm) #1 r e c t r i x (mm) 28.1 (4:25. 6-34.4) 17. 9 (4:17. 0-18. 9) 8.6 (5:7. 9-8.8) 29.3 (13:24.1-34.1) 16.9(9:15.6-18.9) 7.6 (10:7.3-8.2). 12.6(22:9.9-15.9) 13.1 (16:11.2-15.5) 5.4(20:4.8-5.9) 222.6 (6:194.1-259.1) 65.3 (6:61.1-68.1) 27.2 (4:23.7-33.2) 13.3 (4:13.1-13.6) 27.6 (6:25.1-31.3) 228. 2 (15 .-203.6-251. 1) 63. 8 (14:58. 7-70. 1) 29.4(11:27.6-30.7) 10.1 (14:10.7-11.6) 25.3 (5 :24.8-27.3) 80.5 (25:64.1-101.6) 46. 1.(19:36. 2-53. 1) 19.6 (12:18.9-20.1) 8.4 (13:8.1-9.0) 17.8 (7:16.5-19. 2) 280.6 (17:224. 7-316. 2) 84. 0 (3 :81.1-85. 8) 29.6 (3 :29. 2-30.6) 14.2 (3:13.2-15.7) 36. 1 (3 :31.5-39.3) 286.6 (192:250.5-324.6) 75.5 (5 :74.6-76.8) 32.7 (11:30.3-36.1) •12.0(9:10.6-13.5) 31.7(5 :27.6-34.4) 92. 0 (125 :70.2-113. 1) 51.9 (3:51. 2-52.7) 22. .9 (13 :20.7-24.8) 9.9 (15:9.0-12.0) 26. 6 (3 :25. 9-27. 7) 1 0 7 L e g e n d f o r F i g u r e 1 9 G r o w t h o f P a r a k e e t A u k l e t s . M e a n s o f 1 9 6 7 d a t a . o o o o o o o m o in o 10 c\j CM - -( S L U D J 6 ) m&jaM 1 0 8 L e g e n d f o r F i g u r e 20 G r o w t h o f C r e s t e d a n d L e a s t a u k l e t s . M e a n s o f 1 9 6 6 a n d 1 9 6 7 d a t a . 1 0 9 and p u s i l l a , r e s p e c t i v e l y (table 27). The outer primary, t a r s u s , culmen and f i r s t r e c t r i x a l s o average s l i g h t l y l e s s than ad u l t dimensions at t h i s time (tables 21 and 27). I t i s not known whether these dimensions are maintained as y e a r l i n g s or whether ad u l t s i z e i s assumed soon a f t e r departure f o r sea. Storer (1952) determined that there was a s i g n i f i c a n t d i f f e r e n c e i n wing-length between y e a r l i n g and older Cepphus and U r i a . Brody (1945:508) has advocated use of the instantaneous growth r a t e i n growth comparisons; the f i g u r e s are u s u a l l y given as a percentage gain per day. Instantaneous d i a l y percentage growth r a t e s were c a l c u l a t e d using h i s method f o r Parakeet, Crested and Least au k l e t s and presented i n averages i n t a b l e 22; these instantaneous growth r a t e s are from pooled data and the breakdown i n t o age c l a s s e s corresponds to that used by Drent (1965:144). Included i n t a b l e 22 are comparative values of the instantaneous growth r a t e s c a l c u l a t e d by Drent (1965:144) f o r Cepphus  columba from h i s study, Ptychoramphus from Thoresen (1964) and F r a t e r c u l a a r c t i c a from Myrberget (1962). The r a t e of growth of a u k l e t c h i c k s during t h e i r n e s t l i n g stage i s t r e a t e d u s i n g the d e f i n i t i o n provided by Brant (1951:346) who s t a t e d "early r a t e of growth i n the pro g r e s s i v e augmentation of the body as measured by the change i n weight per u n i t of time". By comparing the slopes of the growth curves i n f i g u r e s 19 and 20 and from t a b l e 22 110 L e g e n d f o r T a b l e 22 A v e r a g e d a i l y i n s t a n t a n e o u s g r o w t h r a t e s i n t h e P a r a k e e t , C r e s t e d a n d L e a s t a u k l e t s . D a t a a r e c a l c u l a t e d f r o m m e a n b o d y - w e i g h t s o f s e v e r a l c h i c k s o f k n o w n a g e . C o m p a r a t i v e d a t a f o r t h e P i g e o n G u i l l e m o t , C a s s i n A u k l e t , a n d P u f f i n f r o m T a b l e 9 o f D r e n t ( 1 9 6 5 : 1 4 4 ) , a r e a l s o g i v e n . TABLE 22 Days a f t e r P a r a k e e t C r e s t e d L e a s t P i g e o n Cass i n h a t c h i n g A u k l e t A u k l e t A u k l e t G u i l l e m o t A u k l e t P u f f i n 1-6 15.7 15.7 16.1 14.0 11.1 6.3 7-12 9.1 10.8 9.1 11.1 9.5 10.5 13-18 6.8 5.4 5.3 6.3 7.3 4.7 19-24 1.8 3.6 1.6 2.6 4.5 4.6 25-30 0.3 -0.01 -1.7 2.6 1.6 2.6 31-36 -2.5 -2.7 - 1.3 1.5 0.7 i t i s evident that growth i n Parakeet and Crested a u k l e t s , the a d u l t s of which have s i m i l a r body weights (about 300g), proceeds at a s i m i l a r r a t e u n t i l about the seventh day when the r a t e of growth of the former species lags behind u n t i l about the 20th day. I t i s al s o seen that i n these a u k l e t s a s i g n i f i c a n t weight l o s s occurs immediately p r i o r t o sea-going. Parakeet c h i c k s reach 89.4% of the average a d u l t body weight at about 29 days of age and then l o s e about 10% before d e p a r t i n g to sea; Crested c h i c k s reach 90.8% of the average ad u l t weight at about 27 days of age and then lose about 11% of the adu l t weight before sea-going; Leasts a t t a i n 98.0% of the average ad u l t weight at about 25 days of age and then l o s e 10.5% of the a d u l t weight before going t o sea. Thus, the c h i c k s of the congeners, A. c r i s t a t e l l a and A. p u s i l l a , show n e a r l y i d e n t i c a l p a tterns and r a t e s of growth w h i l e growth of. Cychlorrhynchus c h i c k s d i f f e r s o n l y s l i g h t l y . The p r o p o r t i o n a t e l y more r a p i d growth r a t e of p u s i l l a , the ad u l t s which weigh only about 90g, may p o s s i b l y be due to the s i z e d i f f e r e n c e between i t and the 300-gram c r i s t a t e l l a ( B e l o p o l s k i i , 1961; Brody, 1945); smaller species have l e s s o v e r a l l body mass to i n i t i a l l y accumulate. I t i s not p o s s i b l e at t h i s time to provide an adequate or c o n c l u s i v e e x p l a n a t i o n f o r the pronounced pre-sea-going weight l o s s e x h i b i t e d by these a u k l e t s , 1 1 2 h o w e v e r , some p o s s i b i l i t i e s come t o m i n d . I n F r a t e r c u l a , a s t a r v a t i o n p e r i o d o f 5 - 1 1 d a y s e x i s t s ; t h e n e s t l i n g i s a b a n d o n e d b y i t s p a r e n t s a t a b o u t 3 9 d a y s ( M y r b e r g e t , 1 9 6 2 ) . T h i s m o s t c e r t a i n l y a c c o u n t s f o r t h e c o n s i d e r a b l e w e i g h t l o s s s h o w n b y t h i s s p e c i e s p r i o r t o s e a - g o i n g . I n t h e p r e s e n t s t u d y , f o o d w a s f o u n d i n t h e n e c k - p o u c h o f t w o C y c h l o r r h y n c h u s c h i c k s o n t h e d a y i m m e d i a t e l y p r i o r t o t h e i r d e p a r t u r e t o s e a a n d i t i s s u s p e c t e d t h a t c h i c k s o f A e t h i a s p p . a r e s i m i l a r l y f e d . A n o b s e r v a t i o n o n 17 A u g u s t 1 9 6 7 i s o f i n t e r e s t ; u p o n v i s i t i n g p u s i l i a n e s t n u m b e r 10 a t a b o u t 13 00 h r i t w a s f o u n d t h a t t h e c h i c k h a d d e p a r t e d s i n c e my l a s t v i s i t , t h e p r e v i o u s a f t e r n o o n , a t a n a g e o f 3 0 d a y s . A n a d u l t p u s i l l a w i t h f o o d i n i t s n e c k - p o u c h , p o s s i b l y o n e o f t h e p a r e n t s o f t h i s c h i c k , w a s i n t h e n e s t ; h o w e v e r , s i n c e n e i t h e r p a r e n t s w a s b a n d e d i t i s n o t p o s s i b l e t o b e s u r e i t w a s t h i s c h i c k ' s p a r e n t . D r e n t ( 1 9 6 5 ) f o u n d t h a t C e p p h u s p a r e n t s r e t u r n e d t o t h e i r n e s t i n g g r o u n d a f t e r t h e i r y o u n g h a d f l e d g e d , b u t i n t h e c a s e o f A e t h i a I h a v e n o o b s e r v a t i o n s t o s u g g e s t t h i s . I f e e l , h o w e v e r , t h a t t h i s i s p r o b a b l y n o t t h e c a s e i n a u k l e t s f o r o n c e t h e c h i c k s b e g i n t o l e a v e f o r s e a t h e r e i s a n o t i c e a b l e t h i n n i n g o u t o f a d u l t s i n t h e c o l o n y . I h a v e n o d a t a o n f e e d i n g r a t e s w h i c h m i g h t s u g g e s t a r e d u c t i o n i n t h e a m o u n t o f f o o d b e i n g b r o u g h t t o t h e c h i c k s a t t h i s t i m e a s c o m p a r e d t o t h e f e e d i n g r a t e e a r l i e r i n t h e c h i c k - r e a r i n g s t a g e . A w e i g h t l o s s p r i o r t o s e a - g o i n g 1 1 3 w a s a l s o s h o w n i n U. a a l g e ( J o h n s o n , 1 9 4 4 ) a n d U. l o m v i a ( T u c k , 1 9 6 1 ) b u t n o a t t e m p t w a s m a d e b y e i t h e r a u t h o r t o a c c o u n t f o r t h i s l o s s . T a b l e 22 s h o w s C e p p h u s a n d P t y c h o r a m p h u s e x h i b i t m e r e l y r e t a r d e d g r o w t h p r i o r t o s e a - g o i n g . D a t a f o r t h e p u f f i n w a s c a l c u l a t e d o n l y f o r t h e p e r i o d o f a c t i v e f e e d i n g b y t h e p a r e n t s ( D r e n t , 1 9 6 5 ) „ I t h a s b e e n n o t e d i n m a n y s p e c i e s o f b i r d s t h a t t h e w e i g h t o f g r o w i n g y o u n g i n c r e a s e s t o a p e a k a b o v e n o r m a l a d u l t w e i g h t a n d t h e n d e c r e a s e s b e f o r e f l e d g i n g ( R i c k l e f s , 1 9 6 8 ) . E d s o n ( 1 9 3 0 ) h a s a t t r i b u t e d t h i s p h e n o m e n o n o f w e i g h t r e c e s s i o n t o v a r i o u s c a u s e s ( e . g . , d r y i n g o u t o f t h e f e a t h e r s , h i g h e n e r g y d e m a n d s w i t h r a p i d f e a t h e r g r o w t h , s t a r v a t i o n p e r i o d s , d e c r e a s e i n t h e s i z e o f t h e d i g e s t i v e o r g a n s ) b u t p o i n t e d o u t t h a t l i t t l e e v i d e n c e h a s b e e n s o u g h t t o s u p p o r t a n y o f t h e s e h y p o t h e s e s . R i c k l e f s ( 1 9 6 8 ) a t t r i b u t e d t h i s w e i g h t r e c e s s i o n i n n e s t l i n g B a r n S w a l l o w s ( H i r u n d a r u s t i c a ) t o b e d u e t o t h e h i g h w a t e r c o n t e n t o f e m b r y o n i c t i s s u e s , e s p e c i a l l y f e a t h e r s , a n d t h e l o s s o f w a t e r d u r i n g t h e m a t u r a t i o n o f t h e s e t i s s u e s . S u c h a s i t u a t i o n may b e o p e r a t i v e i n t h e s e a u k l e t s . M a n y c h i c k s , p a r t i c u l a r l y p u s i l l a , w e r e o b s e r v e d e x e r c i s i n g t h e i r w i n g s a t t h e e n t r a n c e s t o t h e i r n e s t -s i t e s j u s t p r i o r t o s e a - g o i n g . T h i s i n c r e a s e d a c t i v i t y a t t h i s t i m e may r e s u l t i n i n c r e a s e d e n e r g y d e m a n d s r e s u l t i n g i n a c o n s e q u e n t d r o p i n b o d y w e i g h t . T h i s r a i s e s 114 the question of the development of the feather coat which i s at t h i s time r a p i d l y approaching completion i n these species. According to B e l o p o l s k i i (1961), the e x t r a energy expended on growth and formation of t r a n s i t i o n a l f eathers i n murres c u r t a i l s the general weight increase of the f l e d g l i n g s . I t i s i n t e r e s t i n g to note t h a t these a u k l e t s have no t r a n s i t i o n a l feather coat or "mesoptile" plumage (see Grasse, 1950) but acquire t h e i r j u v e n a l plumage d i r e c t l y . Kaftanowski (1951) a l s o suggested that the energy d r a i n imposed by the development of the mesoptile plumage reduced the general o v e r a l l weight gain i n U r i a and A l c a , however, the growth pat t e r n s i n a u k l e t s d i f f e r such that the i n t e r p r e t a t i o n s f o r U r i a and A l c a are not g e n e r a l l y a p p l i c a b l e . Growth of the outer primary of each a u k l e t species i s shown i n f i g u r e 21. This primary begins to protrude through the s k i n on about the f i f t h day i n p s i t t a c u l a , s i x t h day i n c r i s t a t e l l a and t h i r d day i n p u s i l l a . Growth i s r a p i d and s i m i l a r i n each species; t h i s primary reaches 11.1%, 84.5% and 88.8% of the a d u l t primary lengths (table 27) i n p s i t t a c u l a , cr i s t a t e l l a and pus i l i a , r e s p e c t i v e l y , before going to sea. Bent (1919:130) s t a t e d of pus i l i a t h a t the "wings begin to sprout when the young b i r d i s about h a l f grown". I t i s p o s s i b l e that he aged these c h i c k s i n c o r r e c t l y as i s the case i n h i s d e s c r i p t i o n of plumage development i n Ptychoramphus where he i n d i c a t e d 115 L e g e n d f o r F i g u r e 2 1 G r o w t h o f t h e o u t e r p r i m a r y i n P a r a k e e t , C r e s t e d a n d L e a s t a u k l e t s . M e a n s o f 1 9 6 6 a n d 1 9 6 7 d a t a . 70 Age (days) 116 (p. 113) t h a t "pinfeathers begin to show at the base of the down when the chick i s but 2 or 3 days o l d " . The v a l i d i t y of Bent's observation i s questioned by Thoresen (1964) who found p r i m a r i e s to protrude through the s k i n between the t w e l f t h and s i x t e e n t h day a f t e r hatching. R e f e r r i n g to Gabrielson and L i n c o l n (1959) who c i t e d the above statement of Bent, Thoresen (1964:467) accounted f o r the apparent discrepancy i n these observations when he s t a t e d "However, 10- t o 12-day-old c h i c k s are s t i l l q u i t e s m a l l , s o f t , and downy and when compared to many other species may e a s i l y be mistaken f o r two- to three-day-old c h i c k s " . As mentioned i n Chapter I I I , the length of the n e s t l i n g periods apparently may d i f f e r from one year to the next. This has been found by B e l o p o l s k i i (1961) to e x i s t when var i o u s p o i n t s i n a species' range are considered and a l s o according t o the time when the p a r t i c u l a r c h i c k s hatch. To i l l u s t r a t e t h i s , B e l o p o l s k i i (1961:228) p l o t t e d the growth curves of two p u f f i n n e s t l i n g s which hatched at an i n t e r v a l of 15 days i n northern Russia. He found a c e r t a i n slowing down of the weight increase of the late-hatched c h i c k compared to the e a r l i e r hatched one, a c o n d i t i o n he a t t r i b u t e d due t o the f a c t t h a t the growth of i t s f e a t h e r s was f a s t e r than those of the f i r s t n e s t l i n g . He found that the remiges appeared on the f i r s t n e s t l i n g on the 13th day w h i l e on the second chick they 1 1 7 a p p e a r e d o n t h e 1 1 t h d a y . T o w a r d t h e 4 5 t h d a y t h e p r i m a r i e s o n t h e f i r s t n e s t l i n g r e a c h e d 82mm a n d o n t h e 3 5 t h d a y t h e y w e r e 70mm o n t h e s e c o n d c h i c k . T h e r a t e o f d e v e l o p m e n t o f t h e p r i m a r i e s w a s 2.6mm p e r d a y i n t h e f i r s t c h i c k a n d 2.9mm p e r d a y i n t h e s e c o n d . T h i s d i f f e r e n t i a l p a t t e r n o f g r o w t h a c c o r d i n g t o t i m e o f h a t c h i n g w a s a l s o s h o w n t o e x i s t i n R e d h e a d s ( A y t h y a a m e r i c a n a ) ( S m a r t , 1 9 6 5 : 5 3 5 ) , w h e r e " n o t o n l y d i d t h e p r i m a r i e s o f t h e l a t e - h a t c h e d g r o u p m a t u r e f a s t e r t h a n d i d t h o s e o f t h e e a r l y h a t c h e d b i r d s , b u t a l s o t h e i r t e n t h p r i m a r i e s g e n e r a l l y m a t u r e d w h e n s h o r t e r t h a n t h o s e o f t h e e a r l y - h a t c h e d g r o u p " . A s i m i l a r d i s p a r i t y i n g r o w t h o f L e a s t A u k l e t c h i c k s i n r e l a t i o n t o t h e i r t i m e s o f h a t c h i n g i n 1 9 6 6 w a s f o u n d . F i g u r e 22 p r e s e n t s a v e r a g e g r o w t h c u r v e s o f L e a s t A u k l e t c h i c k s i n r e l a t i o n t o t h e i r h a t c h i n g d a t e s i n 1 9 6 6 ; t h e d u r a t i o n o f t h e s e c h i c k s ' n e s t l i n g p e r i o d a p p e a r s i n t a b l e 23 ( s a m p l e s i z e i n f i g u r e 22 same a s i n t a b l e 2 3 ) . F i g u r e 23 s h o w s t h e g r o w t h c u r v e s o f t w o p u s i l l a c h i c k s h a t c h e d s e v e n d a y s a p a r t o n S t . L a w r e n c e I s l a n d i n 1 9 6 6 . G r o w t h i n e a c h n e s t l i n g p r o c e e d e d a t t h e sam e r a t e u n t i l a b o u t t h e 1 2 t h d a y w h e n t h e g r o w t h o f t h e f i r s t c h i c k (#169) b e g a n t o p r o c e e d a t a g r e a t e r r a t e . T h e a b r u p t i n c r e a s e s i n w e i g h t o f c h i c k #15 9 o n d a y s 10 a n d 20 may b e e x p l a i n e d b y t h e p r e s e n c e o f f o o d i n i t s n e c k - p o u c h a t . t h e t i m e o f w e i g h i n g . T h e f i r s t c h i c k , h a t c h e d o n 29 J u l y , s h o w e d a s t e a d y w e i g h t i n c r e a s e u n t i l r 1 1 8 L e g e n d f o r F i g u r e 22 G r o w t h i n L e a s t A u k l e t s i n r e l a t i o n t o t h e i r h a t c h i n g d a t e s i n 1 9 6 6 . G r o w t h c u r v e o f c h i c k s h a t c h e d b e t w e e n 2 8 - 3 1 J u l y 1 9 6 6 c o m p u t e d f r o m m e a n s o f f i v e c h i c k s ; g r o w t h c u r v e o f c h i c k s h a t c h e d b e t w e e n 5-6 A u g u s t 1 9 6 6 c o m p u t e d f r o m m e a n s o f t h r e e c h i c k s . Age (days) 1 1 9 L e g e n d f o r F i g u r e 23 * G r o w t h c u r v e s o f A. p u s i l l a c h i c k (#169) h a t c h e d 29 J u l y 1 9 6 6 a n d A. p u s i l l a c h i c h (#159) h a t c h e d 5 A u g u s t 1 9 6 6 . I20-. 100 -80 -E sz 'co 60 -4 0 -20 -0 sea - going (no. 169) sea - going (no. 159) hatching dates : 2 9 J u l y 1966 5 A u g u s t 1966 20 (days) 25 30 35 1 2 0 L e g e n d f o r T a b l e 23 N e s t l i n g p e r i o d s o f L e a s t A u k l e t s i n r e l a t i o n t o t h e i r h a t c h i n g d a t e s , 1 9 6 6 , S t . L a w r e n c e I s l a n d , A l a s k a . T A B L E 23 P e r i o d s o f H a t c h i n g 2 8 - 3 1 J u l y 5-6 A u g u s t H a t c h i n g D a t e N e s t l i n g P e r i o d H a t c h i n g D a t e N e s t l i n g P e r i o d 2 8 J u l y 2 9 J u l y 3 0 J u l y 3 1 J u l y 3 1 J u l y 3 1 d a y s 3 2 d a y s 28 d a y s 30 d a y s 3 1 d a y s 5 A u g u s t 6 A u g u s t 6 A u g u s t 2 9 d a y s 27 d a y s 25 d a y s MEAN 3 0 . 4 d a y s 2 7 . 0 d a y s 121 a b o u t t h e 2 0 t h d a y o f l i f e ; t h e s e c o n d n e s t l i n g , h a t c h e d o n 5 A u g u s t , i n c r e a s e d i n w e i g h t u n t i l a b o u t t h e 1 5 t h d a y . When t h e f i r s t n e s t l i n g r e a c h e d i t s 2 0 t h d a y o f l i f e , i t s w e i g h t h a d a l r e a d y r e a c h e d i t s m a x i m u m ; o n t h e 3 2 n d d a y o f l i f e , w h e n i t f l e w t o s e a , i t s w e i g h t h a d c o n s i d e r a b l y d e c r e a s e d . On i t s 2 0 t h d a y o f l i f e , t h e s e c o n d c h i c k w a s m u c h s m a l l e r b u t c o n t i n u e d t o g r o w f o r t h r e e o r f o u r m o r e d a y s , t h o u g h m o r e s l o w l y , a n d f l e w t o s e a a t 2 9 d a y s o f a g e a n d w e i g h e d l e s s . T h e g r o w t h o f t h e o u t e r p r i m a r i e s i n t h e s e t w o p u s i l i a c h i c k s d i d n o t e x h i b i t p a t t e r n s c o m p l e t e l y s i m i l a r t o t h o s e d e m o n s t r a t e d b y B e l o p o l s k i i a n d S m a r t . T h e p r i m a r i e s a p p e a r e d o n t h e f i r s t c h i c k a t 5 d a y s o f a g e w h i l e o n t h e s e c o n d t h e y a p p e a r e d o n t h e 4 t h d a y ; h o w e v e r , o n t h e 3 2 n d d a y w h e n t h e f i r s t c h i c k f l e w o u t t o s e a , i t s o u t e r p r i m a r y m e a s u r e d 53.1mm w h i l e t h e s e c o n d c h i c k ' s p r i m a r y w a s 44.1mm w h e n i t f l e w o u t a t 2 9 d a y s o f a g e . T h e r a t e o f d e v e l o p m e n t o f t h e p r i m a r i e s w a s 2.1mm p e r d a y i n t h e f i r s t c h i c k a n d 1.8mm p e r d a y i n t h e s e c o n d . I n o t h e r w o r d s , t h e r a t e o f p r i m a r y g r o w t h w a s s l o w e r i n t h e s e c o n d c h i c k . C o n s i d e r i n g t h e d e v e l o p m e n t o f t h e o u t e r p r i m a r i e s o f f i v e p u s i l i a c h i c k s w h i c h h a t c h e d b e t w e e n 2 8 a n d 3 1 J u l y a n d t h r e e c h i c k s w h i c h h a t c h e d b e t w e e n 5 a n d 6 A u g u s t 1 9 6 6 t h e r a t e o f d e v e l o p m e n t o f t h i s p r i m a r y w a s 2.1mm a n d 1.8mm p e r d a y , r e s p e c t i v e l y . F r o m t h e l i m i t e d d a t a a v a i l a b l e i t a p p e a r s t h a t p u s i l l a c h i c k s o f l a t e r - h a t c h i n g s d e v e l o p 1 2 2 t h e i r p l u m a g e s l i g h t l y m o r e s l o w l y b u t a t a n a p p r e c i a b l e s a c r i f i c e i n b o d y w e i g h t . D u e t o h i g h c h i c k l o s s i n 1 9 6 7 t h e s e d i f f e r e n t i a l g r o w t h p a t t e r n s w e r e n o t s t u d i e d . D. T h e r m o r e g u l a t i o n N e s t l i n g s o f b i r d s a r e d i v i d e d i n t o t w o g r o u p s -t h o s e a b l e t o m a i n t a i n m o r e o r l e s s c o n s t a n t b o d y t e m p e r a t u r e s s h o r t l y a f t e r h a t c h i n g ( p r e c o c i a l ) , a n d t h o s e t h a t a r e u n a b l e t o d o t h i s , s o t h a t t h e i r b o d y t e m p e r a t u r e s v a r y w i t h t h e a m b i e n t t e m p e r a t u r e s ( a l t r i c i a l ) . I n t h e A l c i d a e ( e x c e p t E n d o m y c h u r a a n d S y n t h l i b o r a m p h u s w h o s e c h i c k s g o t o s e a a c o u p l e o f d a y s a f t e r h a t c h i n g ) we f i n d a c o n d i t i o n w h e r e t h e c h i c k i s f a i r l y w e l l d e v e l o p e d , a l e r t a n d c o v e r e d w i t h d o w n a t h a t c h i n g ( p r e c o c i a l a t t r i b u t e s ) , b u t r e m a i n s i n t h e n e s t a n d i s f e d b y t h e p a r e n t s u n t i l , i n m a n y c a s e s , i t i s n e a r l y f u l l y g r o w n . A l t h o u g h m u c h i n f o r m a t i o n h a s b e e n a c c u m u l a t e d o n b o d y t e m p e r a t u r e s a n d t h e r m o r e g u l a t i o n i n b i r d s ( s e e B a l d w i n a n d K e n d e i g h , 1 9 3 2 ; S c h o l a n d e r , e t aJL, 1 9 5 0 a , b a n d c ; S m i t h , 1 9 5 8 ; K i n g a n d F a r n e r , 1 9 6 1 ; a n d o t h e r s ) o u r k n o w l e d g e o f t h e o n t o g e n y o f t h e r m o r e g u l a t i o n i s n o t e x t e n s i v e , p a r t i c u l a r l y i n b i r d s w h i c h b r e e d i n a n a r c t i c e n v i r o n m e n t . I n t h i s e n v i r o n m e n t t h e d e v e l o p m e n t o f e f f i c i e n t t h e r m o r e g u l a t i o n a p p e a r s t o b e a c r i t i c a l p e r i o d i n t h e c h i c k s ' l i v e s f o r c o l d r e s i s t e n c e i n b i r d s i s n o t f u l l y d e v e l o p e d a t h a t c h i n g a n d t h e c h i c k s a r e o f t e n e x p o s e d t o l o w t e m p e r a t u r e s u p o n h a t c h i n g . 1 2 3 P r e v i o u s i n v e s t i g a t i o n s o n t e m p e r a t u r e c o n t r o l a n d i t s o n t o g e n y i n t h e A l c i d a e h a v e b e e n c a r r i e d o u t i n t h e R u s s i a n A r c t i c b y K a f t a n o w s k i ( 1 9 5 1 ) a n d R o l n i k ( 1 9 4 8 ) . T h e s e . a u t h o r s p l a c e d n e w l y h a t c h e d c h i c k s i n c o o l e r s o f c . 1 0 ° C a i r t e m p e r a t u r e a n d r e c o r d e d t h e i r b o d y t e m p e r a t u r e s f o r s e v e r a l h o u r s u s i n g t h e r m o c o u p l e s . T h e i r o b s e r v a t i o n s i n d i c a t e a d e q u a t e d e v e l o p m e n t o f t h e r m o r e g u l a t i o n a t a b o u t t h r e e d a y s i n U r i a a a l g e , t h r e e t o f o u r d a y s i n A l c a t o r d a , t h r e e t o f o u r d a y s i n C e p p h u s g r y l l e a n d s i x t o s e v e n d a y s i n F r a t e r c u l a  a r c t i c a . T h e y f o u n d t h a t o n c e t h e r m o r e g u l a t i o n h a d d e v e l o p e d , t h e b o d y t e m p e r a t u r e s o f o l d e r c h i c k s s u b j e c t e d t o p r o l o n g e d c o o l i n g ( 1 4 - 1 6 h o u r s ) r e m a i n e d a l m o s t u n c h a n g e d as' c o m p a r e d t o t h a t b e f o r e t h e b e g i n n i n g o f t h e e x p e r i m e n t . W o r k i n g o h C e p p h u s i n a t e m p e r a t e a r e a , D r e n t ( 1 9 6 5 ) f o u n d t h a t c h i c k s w e r e a b o u t o n e d a y o l d b e f o r e t h e y c o u l d m a i n t a i n s t a b l e b o d y t e m p e r a t u r e s e v e n a t m o d e r a t e a m b i e n t t e m p e r a t u r e s ; t h e i r m e t a b o l i c r e s p o n s e s t o e n v i r o n m e n t a l t e m p e r a t u r e s , h o w e v e r , w e r e a l r e a d y h o m i o t h e r m o u s o n t h e d a y o f h a t c h i n g . R i c h a r d s o n ( 1 9 6 1 ) n o t e d t h a t t e m p e r a t u r e s o f y o u n g C e r o r h i n c a w e r e r a t h e r v a r i a b l e b u t i n d i c a t e d w e l l - e s t a b l i s h e d t e m p e r a t u r e c o n t r o l a t h a t c h i n g o r s o o n a f t e r . On S t . L a w r e n c e I s l a n d , C y c h l o r r h y n c h u s a n d A e t h i a s h o w s l i g h t d i f f e r e n c e s i n t i m i n g o f b r e e d i n g a n d i n n e s t - s i t e s e l e c t i o n , b u t t h e r e i s m u c h o v e r l a p i n b o t h 124 of these aspects of t h e i r breeding c y c l e s . They are s i m i l a r i n the p h y s i o l o g i c a l c h a r a c t e r i s t i c s that I was able to study, and I could not detect any s i g n i f i c a n t d i f f e r e n c e s i n adaptations i n f l u e n c i n g temperature c o n t r o l and i t s development under n a t u r a l c o n d i t i o n s . Each species l a y s i t s eggs among the rocks or i n a c l i f f c r e v i c e which have a remarkably s t a b l e temperature regime (see t a b l e s 14 and 24, f i g u r e 16). The time of hatching and of e a r l y l i f e as n e s t l i n g s on t h i s I s l a n d c o i n c i d e s w i t h the maximum summer temperatures f o r t h i s a r c t i c i s l a n d (see t a b l e s 1, 3 and 4). However, s i n c e the n e s t - s i t e temperatures apparently remain n e a r l y constant throughout the n e s t i n g season, the environmental temperatures d i d not appear to a f f e c t the chi c k s d i r e c t l y . An attempt w i l l be made here to e l u c i d a t e the adaptations f o r s u r v i v a l by c h i c k s during t h e i r e a r l y l i v e s i n a nest micro-environment of about l l ° c . a > Body temperatures and thermoregulation i n auklet chicks Tables 24 and 25 and f i g u r e s 24 t o 27, i n c l u s i v e , r e v e a l t h a t w i t h i n three or four days c h i c k s of p s i t t a c u l a and cr i s t a t e l l a have s u f f i c i e n t l y adequate thermoregulation to maintain e s s e n t i a l l y a d u l t body temperatures or a l i t t l e lower i n the n e s t - s i t e micro-environment of about 11°C. A. p u s i l l a c h i c k s are capable of maintaining steady body temperatures about f i v e days a f t e r hatching. The 1 2 5 L e g e n d f o r T a b l e 24 E s o p h a g e a l t e m p e r a t u r e s i n C y c h l o r r h y n c h u s p s i t t a c u l a , A e t h i a c r i s t a t e l l a , a n d A. p u s i l l a c h i c k s i n r e l a t i o n t o a g e a n d b u r r o w t e m p e r a t u r e . T e m p e r a t u r e s a r e i n ° C . TABLE 24 Age Sample Brooded Mean Mean Burrow Difference (days) Size by Adult Esophageal Temperature Between Chick Temperature and Burrow Temperature Cychlorrhynchus p s i t t a c u l a 0 4 yes 36. 7 11. 1 25.6 1 4 yes 38.4 10. 6 27.8 2 5 yes 39.0 10.6 28.4 3 5 yes 38. 8 10. 0 28. 0 4 3 no 39. 2 11.5 27. 7 5 3 no 39.4 11.4 28. 0 Aethia c r i s t a t e l l a 0 2 yes 37.5 10. 1 27.4 1 2 yes 38. 1 11.5 26. 6 2 2 yes 38. 3 10. 1 28. 2 3 1 yes 38. 3 11. 3 27. 0 4 1 yes 39.0 11.5 27.5 5 1 no 39. 0 11.1 27.. 9 6 1 no 39. 1 11. 6 27.5 Aethia p u s i l l a 0 14 yes 37.0 11. 2 25. 8 1 14 yes 37.8 11. 2 26.6 2 12 yes 38. 0 11.4 26. 6 3 12 yes 38. 2 11.1 27.1 4 12 yes 38.4 11. 2 27. 2 5 9 yes 38.4 11.5 26. 9 6 8 no 38.4 11.2 27. 2 7 6 no 38.5 11. 2 27. 3 8 4 no 38. 7 11. 2 27.5 9 3 no 38. 8 11. 3 27.5 10 2 no 39. 0 11. 3 27. 7 126. L e g e n d f o r T a b l e 25 E s o p h a g e a l t e m p e r a t u r e s o f C y c h l o r r h y n c h u s p s i t t a c u l a , A e t h i a c r i s t a t e l l a , a n d A. p u s i l l a d u r i n g t h e r m o r e g u l a t i o n e x p e r i m e n t s . T e m p e r a t u r e s a r e m e a s u r e d i n ° C . One c h i c k w a s u s e d f o r e a c h e x p e r i m e n t . TABLE 25 Esophageal Temperature Age Brooded A t S t a r t A f t e r 40 minutes i n Change S h i v e r i n g (days) Ambient Temperature about 10°C C y c h l o r r h y n c h u s p s i t t a c u l a 0 yes 37.6 33.5 -4.1 yes 2 yes 39.1 36. 2 -2.9 yes 4 yes 39. 9 38. 1 -1.8 yes 6 no 38. 9 38.8 -0.1 no A e t h i a c r i s t a t e l l a 0 yes 37.1 31. 6 -5.5 yes 1 ye s 38. 2 37.1 -1.1 yes 3 yes 38. 3 37.4 -0.9 yes A e t h i a p u s i l l a 0 yes 38.1 30.9 -7. 2 yes 1 yes 38. 2 30. 8 -7.4 yes 2 yes 39.8 35. 1 -4. 7 yes 3 yes 38. 3 37.0 -1.3 yes 4 yes 38.4 37. 1 -1.3 yes 5 yes 39. 0 38.8 -0. 2 yes 6 no 39. 3 39. 1 -0.2 yes 1 2 7 L e g e n d f o r F i g u r e 24 B o d y t e m p e r a t u r e s i n n e s t l i n g P a r a k e e t , C r e s t e d a n d L e a s t a u k l e t s a f t e r e x p o s u r e t o a m b i e n t t e m p e r a t u r e s a b o u t 1 1 ° C f o r 4 0 m i n u t e s . P l o t t e d w i t h r e s p e c t t o b o d y w e i g h t . 40 - i .9 3 O O O O Parakeet auklet © Crested auklet © Least auklet r 1 1 1 1 1 10 20 30 40 50 60 70 Body weight (grams) 128 L e g e n d f o r F i g u r e 25 R e s p o n s e s o f P a r a k e e t A u k l e t o f a g e s 0 d a y t o 6 d a y s t o a m b i e n t t e m p e r a t u r e s . T h e s a m e c h i c k w a s u s e d t h r o u g h o u t t h e e x p e r i m e n t . A u g u s t , 1 9 6 7 , S t . L a w r e n c e I s l a n d , A l a s k a . 1 2 9 L e g e n d f o r F i g u r e 2 6 R e s p o n s e s o f C r e s t e d A u k l e t o f a g e s 0 d a y t o 3 d a y s t o a m b i e n t t e m p e r a t u r e s . T h e s a m e c h i c k w a s u s e d t h r o u g h o u t t h e e x p e r i m e n t . A u g u s t , 1 9 6 7 , S t . L a w r e n c e I s l a n d , A l a s k a . Temperature ( ° C ) 130 L e g e n d f o r F i g u r e 27 R e s p o n s e s o f L e a s t A u k l e t o f a g e s 0 d a y t o 6 d a y s t o a m b i e n t t e m p e r a t u r e s . T h e s a m e c h i c k w a s u s e d o n e a c h s u c c e s s i v e d a y . J u l y , 1 9 6 7 , S t . L a w r e n c e I s l a n d , A l a s k a . Temperature (PC) a g e s a t w h i c h t h e s e a u k l e t s a r e a b l e t o t h e r m o r e g u l a t e a p p e a r t o c o i n c i d e w i t h t h e c e s s a t i o n o f c o n t i n u o u s b r o o d i n g b y a d u l t s , a t l e a s t d u r i n g t h e d a y . B e d a r d ( 1 9 6 4 ) a n d D r e n t ( 1 9 6 1 ) s h o w e d t h a t o l d e r c h i c k s o f A l c a a n d C e p p h u s , r e s p e c t i v e l y , w e r e b r o o d e d b y t h e p a r e n t s e v e n t h o u g h t h e a b i l i t y t o t h e r m o r e g u l a t e h a d b e e n e s t a b l i s h e d . T h e n a t u r e o f t h e a u k l e t n e s t - s i t e s p r e c l u d e d d i r e c t o b s e r v a t i o n s o f b r o o d i n g a d u l t s a n d t h e o b s e r v a t i o n s p r e s e n t e d i n t a b l e 25 w e r e o b t a i n e d b y n e s t v i s i t a t i o n s t h r o u g h o u t t h e c h i c k -r e a r i n g p e r i o d . S t e a d y b r o o d i n g o c c u r r e d u p t o t h e t i m e i n d i c a t e d i n t a b l e 25 a n d s u b s e q u e n t t o t h a t b r o o d i n g p a r e n t s w e r e n e v e r e n c o u n t e r e d d u r i n g t h e d a y t i m e v i s i t a t i o n p e r i o d . I t i s p o s s i b l e t h a t b r o o d i n g o f o l d e r c h i c k s t o o k p l a c e d u r i n g t h e n i g h t b u t t h i s w a s n o t c h e c k e d . T h o r e s e n ( 1 9 6 4 : 4 6 7 ) f o u n d a s i m i l a r s i t u a t i o n i n P t y c h o r amphu s w h e r e " A p p a r e n t l y t h e a d u l t s n o r m a l l y s t a y w i t h t h e c h i c k d u r i n g t h e d a y u n t i l i t i s t h r e e o r f o u r d a y s o l d a t w h i c h s t a g e t h e c h i c k i s a b l e t o m a i n t a i n i t s own b o d y t e m p e r a t u r e " . T e m p e r a t u r e s o f s e a - g o i n g c h i c k s s h o w e d t h a t a d u l t t e m p e r a t u r e s w e r e a t t a i n e d b y e a c h s p e c i e s . T h e a v e r a g e b o d y t e m p e r a t u r e o f f o u r s e a - g o i n g p s i t t a c u l a c h i c k s w a s 4 0 . 1 ° C , o f s i x c r i s t a t e l l a w a s 4 0 . 0 ° C a n d o f 1 1 p u s i l l a w a s 4 0 . 3 ° C . T h u s , t h e r e a p p e a r s t o b e a n e a r l y a t t a i n m e n t . o f t h e r m o r e g u l a t o r y a b i l i t y a n d a s u b s e q u e n t 132 attainment of ad u l t body temperatures before the c h i c k s depart f o r sea. Table 25 and f i g u r e 24 show that the body temperature of a zero-day-old p s i t t a c u l a chick weighing 26.3g, dropped from 37.6°C to 33.5°C w i t h i n 40 minutes subjected to ambient temperatures of 11.0-11.8°C. Under equal c o n d i t i o n s , a s i m i l a r drop i n temperature of a day-0 cr i s t a t e l l a c h i c k weighing 28.9g was observed. In c o n t r a s t , a 10.6g, day-0 p u s i l l a c h i c k took only about 30 minutes to reach a body temperature of 32.2°C. The small s i z e of p u s i l l a c h i c k s may account f o r t h e i r most r a p i d d e c l i n e i n body temperature under s i m i l a r c o n d i t i o n s . A s i m i l a r c o n c l u s i o n was drawn by Howell (195 9) who found Least Terns (Sterna  a l b i f r o n s ) cooled more r a p i d l y than heavier, young K i t t i w a k e s (Rissa t r i d a c t y l a ) s t u d i e d by R o l n i k (1948) under s i m i l a r c o n d i t i o n s . F i g u r e 24 shows the body temperatures of p s i t t a c u l a , c r i s t a t e l l a and pus i l i a a f t e r exposure to ambient temperatures ,c. 11°C f o r 40 minutes p l o t t e d w i t h respect to body weight. There i s an increase i n thermoregulatory a b i l i t y from hatching to approximate weights of 50g, 45g and 30g i n p s i t t a c u l a , c r i s t a t e l l a and p u s i l l a , corresponding to ages of 3-4 days, 3-4 days and f i v e days, r e s p e c t i v e l y . The slower r a t e of development of temperature c o n t r o l i n p u s i l l a c h i c k s compared to p s i t t a c u l a and c r i s t a t e l l a chicks may p o s s i b l y be accounted f o r by t h e i r smaller s i z e ; newly hatched p u s i l l a c hicks w e i g h 4 3 . 8 p e r c e n t a n d 4 1 . 7 p e r c e n t o f t h e a v e r a g e w e i g h t o f n e w l y h a t c h e d p s i t t a c u l a a n d c r i s t a t e l l a c h i c k s , r e s p e c t i v e l y . T h e s u r f a c e : m a s s r a t i o o f n e w l y h a t c h e d p u s i l l a c h i c k s i s t h u s g r e a t e r t h a n e i t h e r p s i t t a c u l a o r c r i s t a t e l l a , t h u s f a c i l i t a t i n g g r e a t e r h e a t l o s s i n p u s i l l a . T h e s e q u e n c e o f s u b c u t a n e o u s f a t , a n e f f i c i e n t i n s u l a t o r , d e p o s i t i o n i n c h i c k s o f k n o w n a g e w a s s t u d i e d i n 1 9 6 7 a n d i s p r e s e n t e d i n t a b l e 2 6 . E v e n t h o u g h s a m p l e s i z e s a r e s m a l l i t may b e s e e n t h a t i n i t i a l d e p o s i t s o f f a t , o n t h e a b d o m e n a n d a n t e r i o r p a r t o f t h e b a c k , o c c u r a t a b o u t t h r e e d a y s i n p s i t t a c u l a a n d c r i s t a t e l l a a n d a b o u t f i v e d a y s i n p u s i l l a ; t h i s c o r r e s p o n d s c l o s e l y t o t h e o n s e t o f t h e r m o r e g u l a t i o n i n t h e s * e s p e c i e s b u t i t i s n o t k n o w n t h e d e g r e e o f i m p o r t a n c e t o b e a t t a c h e d t o t h i s r e l a t i o n s h i p . I n v i e w o f t h e a p p a r e n t d e m a n d s b y t h e a r c t i c e n v i r o n m e n t o n n e w l y h a t c h e d a u k l e t s , i t i s u s e f u l t o r e v i e w some a s p e c t s o f b e h a v i o r a n d b i o l o g y o f c h i c k s a n d a d u l t s w h i c h a p p e a r t o r e d u c e t h e e f f e c t s o f a c o l d b u t c o n s t a n t n e s t - s i t e m i c r o - e n v i r o n m e n t a n d f a c i l i t a t e s u r v i v a l d u r i n g t h e d e v e l o p m e n t o f t h e r m o r e g u l a t i o n . T h e p r o b l e m o f h e a t c o n s e r v a t i o n a p p e a r s t o b e m e t b y t h e f o l l o w i n g a d a p t a t i o n s d u r i n g t h e e a r l y l i f e o f a u k l e t c h i c k s : 1 3 4 L e g e n d f o r T a b l e 26 S u b c u t a n e o u s f a t d e p o s i t i o n i n c h i c k s o f C. p s i t t a c u l a , A. c r i s t a t e l l a a n d A. p u s i l i a f r o m h a t c h i n g t o s e a - g o i n g . A s c a l e o f 5 ( 0 - 4 ) i s u s e d . TABLE 26 Age of chick in days C. p s i t t a c u l a A. c r i s t a t e l l a A. p u s i l l a 0 0 (2)* 0 (3) 0 (2) 3 1 (2) 1 (1) 0 (2) 5 1 (1) 1 (2) 1 (2) 14 2 (1) 2 (1) 2 (1) 24 3 (2) 3 (2) 4 (3) 28 4 (1) 4 (3) 3** (4) 33 4 (2) 4 (2) 35 3** (3) ' 3** (2) Sample size in parenthesis Sea-going age 1 3 5 (1) C h i c k s a r e c o v e r e d w i t h f i n e , l o n g d o w n a t t h e t i m e o f h a t c h i n g , a n d t h i s d o w n i s r e t a i n e d u n t i l g r a d u a l l y r e p l a c e d b y t h e j u v e n a l p l u m a g e ; t h u s , t h e c h i c k s a r e w e l l i n s u l a t e d a t a l l s t a g e s o f g r o w t h . T h e l e n g t h o f t h e d o w n o n p a r t s o f t h e b o d y , m e a s u r e d i n m i l l i m e t e r s , o f o n e - d a y - o l d c h i c k s o f p s i t t a c u l a , c r i s t a t e l l a a n d p u s i l l a , r e s p e c t i v e l y , w e r e a s f o l l o w s : c r o w n , 7; d o r s u m , 1 6 ; v e n t o r , 8; w i n g s , 1 3 . C r o w n , 8; d o r s u m , 1 4 ; v e n t o r , 8; w i n g s , 1 1 . C r o w n , 6; d o r s u m , 1 3 ; v e n t o r , 7; w i n g s , 7. (2) A u k l e t s l a y t h e i r e g g s a n d r a i s e t h e i r y o u n g i n n e s t - s i t e s w h i c h h a v e a v e r y s t a b l e m i c r o - e n v i r o n m e n t a l t e m p e r a t u r e . (3) T h e c h i c k i s c o n t i n u a l l y b r o o d e d b y t h e p a r e n t s a f t e r h a t c h i n g f o r a b o u t t h r e e d a y s i n p s i t t a c u l a , a b o u t f o u r d a y s i n c r i s t a t e l l a a n d a b o u t f i v e d a y s i n p u s i l i a ; t h i s p e r i o d o f b r o o d i n g c o i n c i d e s w i t h t h e a g e a t w h i c h t h e s e s p e c i e s ' a r e c a p a b l e o f m a i n t a i n i n g c o n s t a n t b o d y t e m p e r a t u r e s . I t i s n o t k n o w n t o w h a t e x t e n t i f a n y o l d e r c h i c k s a r e b r o o d e d a n d n i g h t b r o o d i n g t a k e s p l a c e . (4) Y o u n g , s e m i - p r e c o c i a l a u k l e t c h i c k s r e m a i n i n t h e n e s t - s i t e a n d a r e f e d b y t h e p a r e n t s ; c o n s e q u e n t l y m o r e e n e r g y c a n b e u s e d f o r m o r e r a p i d g r o w t h a n d f o r m o r e r a p i d d e v e l o p m e n t o f e f f i c i e n t t h e r m o r e g u l a t i o n . T h i s p o i n t i s d i s c u s s e d b y K o s k i m i e s a n d L a h t i ( 1 9 6 4 ) . (5) S h i v e r i n g , a n i m p o r t a n t m e a n s o f e x t r a h e a t p r o d u c t i o n i n b i r d s ( W e s t , 1 9 6 5 ) , o c c u r r e d i n e a c h s p e c i e s 136 soon a f t e r exposure to temperatures c. 11 C d u r i n g t h e i r e a r l y l i f e . (6) Subcutaneous f a t , an e f f i c i e n t i n s u l a t o r , was d e p o s i t e d w i t h i n the f i r s t few days of l i f e i n c h i c k s of each s p e c i e s . (7) The r a t e of c o o l i n g of a hot body depends on i t s s u r f a c e area and m o d i f i c a t i o n s i n the e f f e c t i v e area are achieved by a l t e r a t i o n s i n p o s t u r e (Davson, 1964). The t y p i c a l p o s t u r e of a newly hatched a u k l e t c h i c k i s a huddled p o s i t i o n u s u a l l y i n a corner of the n e s t c r e v i c e . ' (8) The development o f the f e a t h e r coat, i n i t i a l l y composed l a r g e l y of b l o o d - q u i l l s which i n c r e a s e the s u r f a c e area through which b l o o d i s f l o w i n g and consequently the a r e a through which heat may be l o s t , develops a f t e r e s s e n t i a l l y adequate t h e r m o r e g u l a t i o n s e t s i n . E - F l e d g i n g of Chicks Parakeet, Crested and Least a u k l e t c h i c k s depart f o r sea, on the average, at 35, 34 and 29 days of age, r e s p e c t i v e l y , when they are f u l l y f e a t h e r e d i n the j u v e n a l plumage and w i t h homiothermy comparable to t h a t of the a d u l t s . Table 27 r e v e a l s the s l i g h t l y s m a l l e r s i z e s of the c h i c k s a t sea-going compared t o a d u l t s . D e s p i t e the f a c t t h a t c h i c k s are s m a l l e r at sea-going than a d u l t s , t h e i r wing areas r e l a t i v e to t h e i r body weights are high, 1 3 7 L e g e n d f o r T a b l e 27 S u m m a r y o f r e l a t i v e c h i c k b o d y - w e i g h t s a n d m e a s u r e m e n t s t o a d u l t b o d y - w e i g h t s a n d m e a s u r e m e n t s i n C_. p s i t t a c u l a , A. c r i s t a t e l l a , a n d A. p u s i l l a . TABLE 27 _C. p s i t t a c u l a A. c r i s t a t e l l a A. p u s i l l a we i g h t o u t e r primary-t a r s u s culmen #1 r e c t r i x 79. 3% 77. 7% 91. 8% 93.6% 76.4% 79. 6% 84.5% 89. 9% 84. 1% 79.8% 87.5% 88. 8% 85.5% 84.8% 76. 9% 1 3 8 i n f a c t , i n c r i s t a t e l l a t h e y a r e h i g h e r t h a n t h a t o f t h e a d u l t s ( t a b l e 2 8 ) . A n e x p l a n a t i o n f o r t h e f a c t t h a t w i n g l o a d i n g i n a d u l t s v e r s u s c h i c k s i s s m a l l e r i n c r i s t a t e l l a a n d l a r g e r i n t h e o t h e r t w o s p e c i e s i s n o t o b v i o u s . T h e l a r g e r w i n g a r e a o f a d u l t p s i t t a c u l a may p o s s i b l y b e a c c o u n t e d f o r b y i t s a p p a r e n t m o r e e x t e n s i v e m i g r a t i o n s , h o w e v e r , i n f o r m a t i o n i n t h i s r e g a r d i s s c a n t y . T h e f e e d i n g m e t h o d s a n d p a t t e r n s o f p u r s u i t o f p r e y may a l s o b e i m p o r t a n t h e r e w h e n c o n s i d e r i n g w i n g l o a d i n g . S e a - g o i n g b y a u k l e t c h i c k s , w h i c h t a k e s p l a c e p r i m a r i l y a t n i g h t a n d e a r l y m o r n i n g , w a s o b s e r v e d o n n u m e r o u s o c c a s i o n s i n 1 9 6 7 . M a n y c h i c k s w e r e a l s o o b s e r v e d e x e r c i s i n g t h e i r w i n g s a t t h e e n t r a n c e s o f t h e i r n e s t - s i t e s d u r i n g d a y l i g h t h o u r s . S e v e r a l c r i s t a t e l l a a n d p u s i l l a c h i c k s f l e w o u t s i n g l y t o s e a a t m i d - d a y b u t n o n e w a s o b s e r v e d l e a v i n g a t d u s k a s i s common i n U r i a s p p . ( T u c k , 1 9 6 1 ) a n d C. g r y l l e ( W i n n , 1 9 5 0 ) . B e d a r d ( 1 9 6 7 ) p r e s u m e d t h a t m o s t a u k l e t c h i c k s l e f t f o r s e a d u r i n g t h e n i g h t a n d e a r l y m o r n i n g a n d D r e n t ( 1 9 6 5 ) f e l t t h a t _C. c o l u m b a c h i c k s a l s o d e p a r t e d a t t h i s t i m e . A c c o r d i n g t o L o c k l e y ( 1 9 5 3 ) , p u f f i n c h i c k s a l s o l e a v e t h e i r b u r r o w s a t n i g h t a n d g o t o s e a a s d o c h i c k s o f S y n t h 1 i b o r amphu s ( D r e n t a n d G u i g u e t , 1 9 6 1 ) . U p o n b e c o m i n g a i r - b o r n e , a u k l e t c h i c k s f l y d i r e c t l y t o s e a a t r i g h t a n g l e s t o t h e s l o p e d e p e n d i n g u p o n t h e 139 Legend f o r T a b l e 28 Body-weights and w i n g a r e a r a t i o s o f a u k l e t s (method o f c a l c u l a t i o n f o l l o w s P o o l e , 1938). TABLE 28 Species Mean Body Wing Area Wing Area Weight i n (cm2) P e r 9" r a m (g) c. p s i t t a c u l a (adults) 280. 6 (17) * 415. 4 1. 480 c. p s i t t a c u l a (sea-going chicks) 222. 6(6) 249. 7 1. 121 A. c r i s t a t e l l a (adults) 286. 6 (192) 254. 8 o. 889 A. c r i s t a t e l l a (sea-going chicks) 228. 2(15) 229. 2 1. 004 A. p u s i l l a (adults) 92. 0(125) 132. 9 1. 444 A. p u s i l l a (sea-going chicks) 80. 5 (25) 96. 4 1. 197 * Body-weight sample s i z e i n parenthesis 1 4 0 d i r e c t i o n o f t h e w i n d . T h e i r f l i g h t a p p e a r e d t o b e f a i r l y s t r o n g a n d d i r e c t w i t h l a n d i n g o n t h e w a t e r o c c u r r i n g a b o u t o n e - h a l f km f r o m s h o r e , a f e w i n s t a n c e s w i t h i n 1 00m f r o m s h o r e . T h e a d u l t s a r e n o t d i r e c t l y i n v o l v e d w i t h t h e f l y i n g o u t o f t h e c h i c k s a n d i t a p p e a r s t h a t t h e c h i c k s a r e c o m p l e t e l y i n d e p e n d e n t o n c e a t s e a . W i n n ( 1 9 5 0 ) a n d T h o r e s e n a n d B o o t h ( 1 9 5 8 ) s t a t e d t h a t j u v e n i l e C e p p h u s a r e c o a x e d o u t o f t h e n e s t b y t h e p a r e n t s w h i c h d a n g l e f i s h i n f r o n t o f t h e m . A c c o r d i n g t o B e d a r d ( 1 9 6 4 ) A l c a c h i c k s , w h i c h l e a v e f o r s e a a t d u s k , a r e c o a x e d b y o n e p a r e n t t o l e a v e t h e n e s t - s i t e a n d f l u t t e r t o s e a . On 2 1 A u g u s t 1 9 6 7 a p u s i l l a c h i c k , 2 8 d a y s o f a g e , w a s r e l e a s e d a t 0 4 0 0 h r f r o m a b o u t 100m e l e v a t i o n o n t h e n e s t i n g s l o p e . I t f l e w d i r e c t l y t o w a r d t h e w a t e r a n d a l i g h t e d a b o u t o n e km f r o m s h o r e w h e r e i t b e g a n t o s w i m o u t t o s e a a n d d i v e w i t h i n 10 m i n u t e s a f t e r a l i g h t i n g . On 24 A u g u s t a y o u n g p s i t t a c u l a w a s o b s e r v e d f l y i n g o u t t o s e a a t 0 3 0 0 h r d u r i n g a m o d e r a t e w i n d . I t r e m a i n e d a i r - b o r n e f o r a b o u t t h r e e m i n u t e s b e f o r e d r o p p i n g d o w n t o n e a r l y w a t e r - l e v e l t h e n a l i g h t e d . On 2 S e p t e m b e r t w o y o u n g c r i s t a t e l l a w e r e o b s e r v e d a b o u t 200m f r o m s h o r e a t 1 3 3 0 h r ; m a n y d i v e s o f 25 t o 35 s e c o n d s d u r a t i o n w e r e u n d e r t a k e n . No a d u l t s w e r e s e e n o n t h e w a t e r w i t h t h e s e c h i c k s . I n c l e m e n t w e a t h e r a d v e r s e l y a f f e c t e d t h e s u r v i v a l o f m a n y s e a - g o i n g c h i c k s d u r i n g b o t h s e a s o n s . D u r i n g h i g h w i n d s w h i c h p r e v a i l e d i n t e r m i t t e n t l y d u r i n g t h e s e a - g o i n g p e r i o d s i n e a c h y e a r , m a n y c h i c k s w e r e b l o w n " o f f c o u r s e " w h e n a t t e m p t i n g t o f l y o u t t o s e a . S e v e r a l p u s i l l a c h i c k s w e r e f o u n d d e a d f r o m o n e - h a l f t o t h r e e km b a c k o n t h e t u n d r a o n t o p o f S e v u o k u k M o u n t a i n ; t h e y h a d b e e n b l o w n t h e r e b y s t r o n g w i n d . On 1 S e p t e m b e r 1 9 6 6 a t 1 1 3 0 h r I o b s e r v e d o n e p u s i l l a c h i c k a t t e m p t i n g t o f l y o u t f r o m t h e t o p o f t h e M o u n t a i n . S o o n a f t e r i t b e c a m e a i r - b o r n e i t w a s c a u g h t b y w i n d a n d s w e p t b a c k o n t o t h e t u n d r a a b o u t o n e km a w a y . I t i s d o u b t f u l t h a t m a n y o f t h e s e c h i c k s w o u l d s u r v i v e f o r j a e g e r s c o m m o n l y p a t r o l t h i s a r e a a t t h i s t i m e . On 1 S e p t e m b e r 1 9 6 7 a c r i s t a t e l l a c h i c k w a s f o u n d r u n n i n g o n t h e g r a v e l n e a r G a m b e l l , p r o b a b l y b l o w n t h e r e d u r i n g i t s d e s c e n t t o s e a f r o m t h e w e s t s l o p e o f t h e M o u n t a i n . On s i x o c c a s i o n s i n 1 9 6 6 s i n g l e p u s i l l a c h i c k s w e r e f o u n d d e a d o n t h e n e s t i n g s l o p e h u d d l e d a g a i n s t a r o c k w i t h f e e t d r a w n u n d e r t h e m . T h e s e v e r e c h i l l i n g f o r c e o f t h e w i n d h a d e v i d e n t a l l y c a u s e d t h e i r d e a t h s . A s a l s o p o i n t e d o u t b y B e d a r d ( 1 9 6 7 ) , m a n y f l e d g l i n g s w h i c h g o t o s e a o n s t o r m y d a y s s e e m u n a b l e t o e s c a p e t h e s t r o n g t i d e r i p s a n d c u r r e n t s t h a t p r e v a i l a t t h e b a s e o f S e v u o k u k M o u n t a i n a n d m a n y w e r e f o u n d d y i n g o n n e a r - b y b e a c h e s . T h e i m p a c t o f s u c h m o r t a l i t y i s i m p o s s i b l e t o a s s e s s b e c a u s e l a r i d s r e m o v e t h e c a r c a s s e s b e f o r e t h e o b s e r v e r h a s a c h a n c e t o o b t a i n a q u a n t i t a t i v e s a m p l e 1 4 2 ( B e d a r d , 1 9 6 7 ; t h i s s t u d y ) a n d t h e i n a c c e s s i b l e n a t u r e o f t h e n e s t - s i t e s p r e c l u d e d d e t e r m i n i n g t h e n u m b e r o f c h i c k s i n i t i a l l y p r o d u c e d i n t h e c o l o n y . On 13 S e p t e m b e r 1 9 6 6 w i n d - b l o w n s n o w f e l l o n t h e n e s t i n g s l o p e , h o w e v e r , i t w a s l i g h t , d i d n o t f i l l a u k l e t n e s t i n g c r e v i c e s a n d w a s a p p a r e n t l y n o t h a r m f u l t o a u k l e t s . T a b l e 2 9 s u m m a r i z e s s e a - g o i n g d a t e s o f P a r a k e e t , C r e s t e d a n d L e a s t a u k l e t s i n n e s t s s t u d i e d i n 1 9 6 6 a n d 1 9 6 7 . 143 L e g e n d f o r T a b l e 2 9 S e a - g o i n g d a t e s o f C. p s i t t a c u l a , A. c r i s t a t e l l a , a n d A., p u s i l l a o n S t . L a w r e n c e I s l a n d , A l a s k a , i n 1 9 6 6 a n d 1 9 6 7 T A B L E 29 1 9 6 6 1 9 6 7 N u m b e r D a t e o f S e a - g o i n g N u m b e r D a t e o f S e a - g o i n g C. p s i t t a c u l a 1 1 S e p t e m b e r N u m b e r o f c a s e s M e a n .2 1 2 1 2 1 1 1 0 S e p t e m b e r 2.1 A. c r i s t a t e l l a 1 1 3 1 1 1 1 1 1 5 S e p t e m b e r 7 S e p t e m b e r 8 S e p t e m b e r 9 S e p t e m b e r 10 S e p t e m b e r 1 1 S e p t e m b e r 12 S e p t e m b e r 13 S e p t e m b e r 14 S e p t e m b e r 5 1 2 .1 1 N u m b e r o f c a s e s 1 1 M e a n S e p t e m b e r 9.8 I'O S e p t e m b e r 3.0 A. p u s i l l a 3 6 4 1 1 1 1 28 A u g u s t 30 A u g u s t 3 1 A u g u s t 1 S e p t e m b e r 2 S e p t e m b e r 3 S e p t e m b e r 7 S e p t e m b e r 1 '2 1 4 1 .1 1 2 2 9 A u g u s t 3 1 A u g u s t 1 S e p t e m b e r 2 S e p t e m b e r 3 S e p t e m b e r 4 S e p t e m b e r 7 S e p t e m b e r S e p t e m b e r S e p t e m b e r S e p t e m b e r S e p t e m b e r S e p t e m b e r 15 A u g u s t 17 A u g u s t 18 A u g u s t 1 9 A u g u s t 2 1 A u g u s t 23 A u g u s t 25 A u g u s t 26 A u g u s t N u m b e r o f c a s e s 17 1 3 M e a n S e p t e m b e r 1.1 A u g u s t 2 0 . 5 1 4 4 C H A P T E R I V . P r e d a t i o n A s p o i n t e d o u t b y B e d a r d ( 1 9 6 7 ) , p r e d a t i o n u p o n a u k l e t s w a s l o w o n S t . L a w r e n c e I s l a n d . T h e r e a s o n f o r t h i s i s n o t o b v i o u s f o r q u a l i t a t i v e o b s e r v a t i o n s m ade a t v a r i o u s o t h e r a l c i d c o l o n i e s s h o w t h a t t h e y a r e g e n e r a l l y p l a g u e d b y a h o s t o f p r e d a t o r s ( L a r s o n , 1 9 6 0 ; S a l o m o n s e n , 1 9 5 1 ; T u c k , 1 9 6 1 ; a n d o t h e r s ) . A u s t i n ( 1 9 3 2 ) s t a t e d t h a t t h e m a i n r e q u i s i t e t o d a y f o r a s u c c e s s f u l c o l o n y o f p u f f i n s i s t h a t i t s h o u l d b e i n a c c e s s i b l e t o man a n d p r e d a t o r y a n i m a l s . T h e n o c t u r n a l b r e e d i n g h a b i t s p f m a n y l o w a r c t i c a n d b o r e a l P a c i f i c a l c i d s ( e . g . , S y n t h 1 i b o r a m p h u s , E n d o m y c h u r a , P t y c h o r amphu s, C e r o r h i n c a ) p r o b a b l y d e v e l o p e d t o c u r t a i l a e r i a l p r e d a t i o n ( B e d a r d ( 1 9 6 7 ) . T h i s c a n n o t h o l d e n t i r e l y t r u e o n S t . L a w r e n c e I s l a n d a n d o t h e r a r c t i c a l c i d c o l o n i e s f o r a 2 4 - h o u r p h o t o p e r i o d p r e v a i l s d u r i n g t h e g r e a t e r p o r t i o n o f t h e b r e e d i n g s e a s o n . A e r i a l p r e d a t o r s w e r e f e w , h o w e v e r , i n t h e S e v u o k u k c o l o n y . P e r e g r i n e F a l c o n s ( F a l c o p e r e g r i n u s ) , d e e m e d i m p o r t a n t a e r i a l p r e d a t o r s o n a l c i d s ( G a b r i e l s o n a n d L i n c o l n , 1 9 5 9 ; M u r i e , 1 9 5 9 ) , a r e r e p r e s e n t e d i n t h i s I s l a n d ' s a v i f a u n a b y o n l y t w o i s o l a t e d r e c o r d s ( B a i l e y , 1 9 5 6 ; S e a l y , F a y a n d B e d a r d , m a n u s c r i p t i n p r e p a r a t i o n ) . I t s c o n g e n e r , t h e G y r f a l c o n , i s a l s o r e l a t i v e l y u n c ommon o n S t . L a w r e n c e I s l a n d ( F a y a n d C a d e , 1 9 5 9 ) . I n 1 9 6 6 I o b s e r v e d f o u r 145 G y r f a l c o n s i n t h e v i c i n i t y o f t h e Sevuofouk c o l o n y ; one seen on 17 June p u r s u i n g an a d u l t A. c r i s t a t e l l a was l o s t b e f o r e t h e outcome of t h e chase c o u l d be a s c e r t a i n e d . Rough-legged Hawks (Buteo lagopus) whicln were n o t o b s e r v e d d u r i n g t h e s t u d y have been r e c o r d e d t a k i n g C y c h l o r r h y n c h u s and A e t h i a . (Fay and Cade, 1959). I t i s d i f f i c u l t t o account f o r t h e p a u c i t y o f t h e s e o p p o r t u n i s t i c p r e d a t o r s on S t . Lawrence I s l a n d . Bedard (1967) f e e l s th\at f o g , a p r e v a l e n t c l i m a t i c f e a t u r e i n summer on t h i s I s l a n d , may be r e s p o n s i b l e t h r o u g h r e d u c i n g t h e p r e d a t o r s ' h u n t i n g e f f i c i e n c y . T h i s cannot be t h e o v e r a l l f a c t o r f o r f o g i s an i n t e g r a l p a r t o f t h e c l i m a t e o f t h e A l e u t i a n I s l a n d s ( M u r i e , 1959) where, a c c o r d i n g t o G a b r i e l s o n and L i n c o l n (1959:285), p r e d a t i o n by t h e P e a l e ' s F a l c o n (F. p_. p e a l e i ) i s " s e v e r e " i n n e a r l y e v e r y A l e u t i a n c o l o n y . Cade (I960) a l s o f a i l e d t o o f f e r an e x p l a n a t i o n c o n c e r n i n g t h e absence o f b r e e d i n g f a l c o n s on t h e n o r t h B e r i n g Sea i s l a n d s d e s p i t e numerous p o t e n t i a l n e s t i n g c l i f f s and abundant f o o d . J a e g e r p r e d a t i o n was a p p a r e n t l y n e g l i g i b l e i n b o t h summers. On 8 June 1966 a Pomarine J a e g e r was f l u s h e d from a f r e s h l y k i l l e d A. pus i l i a b u t i t i s n o t known whether the j a e g e r k i l l e d t h a a a k l e t or was m e r e l y s c a v e n g i n g . L o n g - t a i l e d J a e g e r s were o b s e r v e d h u n t i n g i n t h e c o l o n y on numerous o c c a s i o n s ; however, upon a n a l y s i s o f f i v e stomachs i t was found t h a t m i c r o t i n e r o d e n t s were b e i n g 146 t a k e n . F a y a n d C a d e ( 1 9 5 9 ) e x a m i n e d 10 L o n g - t a i l e d J a e g e r s t o m a c h s t a k e n i n A u g u s t ( t h e a u k l e t c h i c k - r e a r i n g p e r i o d ) , 1 9 5 6 a n d 1 9 5 7 ; s e v e n c o n t a i n e d M i c r o t u s , t w o c o n t a i n e d i n s e c t s a n d o n e h a d e a t e n a f i s h . S n o w y O w l s ( N y e t e a s c a n d i a c a ) w e r e o b s e r v e d f i v e t i m e s b e t w e e n 29 J u n e a n d 2 S e p t e m b e r 1 9 6 7 n e a r t h e S e v u o k u k c o l o n y b u t n o t i n i t . R a v e n s n e s t e d i n t h e c o l o n y f o r t h e l a s t f o u r y e a r s ( f r o m t h e b e g i n n i n g o f B e d a r d ' s s t u d y t o t h e e n d o f t h e p r e s e n t s t u d y ) b u t a p p a r e n t l y a s s u m e d t h e r o l e o f a s c a v e n g e r r a t h e r t h a n a p r e d a t o r . G l a u c o u s - w i n g e d G u l l s a n d K i t t i w a k e s w e r e o b s e r v e d o f t e n i n t h e c o l o n y ; t h e f o r m e r p r o b a b l y t a k e s s o me a u k l e t e g g s a n d y o u n g b u t t h e l a t t e r i s p r i m a r i l y a p l a n k t o n - f e e d e r ( T u c k , 1 9 6 1 ) . H e r r i n g G u l l s , w h i c h n e s t o n t h e s o u t h s i d e o f t h e I s l a n d ( F a y a n d C a d e , 1 9 5 9 ) , e l i c i t m a s s i v e p a n i c f l i g h t s b y t h e i r m e r e a p p e a r a n c e ( B e d a r d , 1 9 6 7 ; t h i s s t u d y ) , e s p e c i a l l y a m o n g A. p u s i l l a . T h r e e a d u l t H e r r i n g G u l l s w e r e c o l l e c t e d i n t h e S e v u o k u k c o l o n y i n A u g u s t , 1 9 6 7 , a n d t h e i r s t o m a c h s w e r e e x a m i n e d . E a c h o f t w o o f t h e s t o m a c h s c o n t a i n e d o n e p a r t i a l l y d i g e s t e d p u s i l l a c h i c k a n d t h e o t h e r w a s e m p t y . P r e d a t i o n b y G l a u c o u s G u l l s w a s n o t o b s e r v e d i n t h i s c o l o n y . A r c t i c f o x e s ( A l o p e x l a g o p u s ) a n d s l e d g e d o g s ( C a n i s f a m i l i a r i s ) w e r e a c t i v e i n t h e S e v u o k u k c o l o n y b u t t h e i r i m p a c t o n t h e p o p u l a t i o n w a s n o t a s c e r t a i n e d . T h r e e s l e d g e d o g s ( e s c a p e e s f r o m G a m b e l l ) l i v e d t h e summer 147 o f 1 9 6 7 i n t h e S e v u o k u k c o l o n y , p a r t i c u l a r l y o n t h e w e s t s l o p e o f t h e M o u n t a i n , a n d o n n u m e r o u s o c c a s i o n s w e r e s e e n h u n t i n g a m o n g t h e b o u l d e r s p r e s u m a b l y f o r a u k l e t s . A u k l e t r e m a i n s ( p r e d o m i n a n t l y c r i s t a t e l l a ) w e r e o f t e n f o u n d n e a r d o g t r a c k s a n d f e c e s . T h e n a t u r e o f t h e n e s t i n g h a b i t s o f A e t h i a s p p . a n d some t a l u s s l o p e - n e s t i n g C y c h l o r r h y n c h u s r e n d e r t h e m v u l n e r a b l e t o f o x p r e d a t i o n a n d i n d e e d t h i s a n i m a l i s a n i m p o r t a n t p r e d a t o r i n o t h e r a l c i d c o l o n i e s o n S t . L a w r e n c e I s l a n d , w h i c h a r e r e l a t i v e l y f r e e o f h u m a n m o l e s t a t i o n , f o r e x a m p l e , t h e K o n g k o k c o l o n y ( B e d a r d , 1 9 6 7 ; F a y a n d C a d e , 1 9 5 9 ) . C l i f f - n e s t i n g C y c h l o r r h y n c h u s a r e r e l a t i v e l y f r e e f r o m t e r r e s t i a l p r e d a t o r s . A l t h o u g h t h e t u n d r a s h r e w , a r c t i c g r o u n d s q u i r r e l , r e d - b a c k e d v o l e a n d t u n d r a v o l e l i v e i n j u x t a p o s i t i o n t o t h e n e s t i n g a u k l e t s o n S e v u o k u k M o u n t a i n , n o d i r e c t e v i d e n c e t h a t s h r e w s o r g r o u n d s q u i r r e l s p r e y e d o n t h e s e b i r d s w a s o b t a i n e d . T h e m e a t - e a t i n g t e n d e n c i e s o f t h e g r o u n d s q u i r r e l o n S t . L a w r e n c e I s l a n d h a v e b e e n d o c u m e n t e d b y G e i s t ( 1 9 3 3 ) a n d C a d e ( 1 9 5 1 ) . B o t h a u t h o r s r e p o r t e d t h i s s p e c i e s f e e d i n g o n o t h e r g r o u n d s q u i r r e l s a s w e l l a s o t h e r m a m m a l s ; h o w e v e r , t h e y w e r e n o t o b s e r v e d e a t i n g b i r d s . R e f e r r i n g t o s h r e w s , g r o u n d s q u i r r e l s a n d t u n d r a v o l e s , F a y a n d C a d e ( 1 9 5 9 : 8 1 ) s t a t e t h a t " S i n c e e a c h o f t h e s e m a m m a l s l i v e s i n j u x t a p o s i t i o n t o n e s t i n g b i r d s , we s u s p e c t t h a t some e g g s a n d y o u n g may b e e a t e n b y t h e m " . 1 4 8 B e d a r d ( 1 9 6 7 ) d i d n o t o b s e r v e g r o u n d s q u i r r e l s n o r r e d -b a c k e d v o l e s i n t e r a c t i n g d i r e c t l y w i t h a u k l e t s b u t h e l d t h e m r e s p o n s i b l e f o r a l a r g e p r o p o r t i o n o f d e a t h s a m o n g e m b r y o s a n d c h i c k s ; t h e l a t t e r w e r e o f t e n f o u n d m u t i l a t e d i n a w a y t h a t i n d i c a t e d r o d e n t p r e d a t i o n . S e v e n g r o u n d s q u i r r e l s s t o m a c h s , e x a m i n e d b y me i n 1 9 6 6 , c o n t a i n e d p l a n t m a t e r i a l , p r e d o m i n a n t l y S a x i f r a g a a n d Sedum, w h i c h g r e w b e t w e e n t h e r o c k " s t r i p e s " o n t h e t a l u s s l o p e . M u r i d r o d e n t p r e d a t i o n o n s e a - b i r d s h a s b e e n d o c u m e n t e d b y H a g u e ( 1 8 6 2 ) , H o w l a n d ( 1 9 5 5 ) a n d K e p l e r ( 1 9 6 7 ) . K e p l e r ( 1 9 6 7 ) d e s c r i b e d p r e d a t i o n b y P o l y n e s i a n r a t s ( R a t t u s e x u l a n s ) o n L a y s a n A l b a t r o s s e s ( D i o m e d e a  i m m u t a b i l i s ) o n K u r e A t o l l , t h e w e s t e r n m o s t a t o l l i n t h e H a w a i i a n L e e w a r d I s l a n d s . He f o u n d m a n y d y i n g a n d d e a d a d u l t a l b a t r o s s e s w i t h l a r g e g a p i n g w o u n d s i n t h e i r b a c k s w h i c h h e l a t e r a t t r i b u t e d t o r a t p r e d a t i o n . A s i m i l a r s i t u a t i o n e x i s t e d o n S t . L a w r e n c e I s l a n d i n v o l v i n g t h e t h r e e a u k l e t s p e c i e s a n d C l e t h r i o n o m y s a n d M i c r o t u s . S e v e r a l a u k l e t s o f s e a - g o i n g a g e w e r e f o u n d w i t h o p e n w o u n d s o n t h e i r b a c k s , t h e w o r k o f v o l e s . T h e s e w o u n d s w e r e a l w a y s o n t h e d o r s u m o f t h e b i r d s , u s u a l l y j u s t a n t e r i o r t o t h e u r o p y g i a l g l a n d s b u t i n o n e i n s t a n c e , a c r i s t a t e l l a c h i c k , t h e w o u n d e x t e n d e d f r o m t h e n a p e t o t h e p o s t e r i o r b o r d e r o f t h e s c a p u l a e . C l o s e e x a m i n a t i o n o f t h e w o u n d s s h o w e d t h a t o n l y t h e s k i n w a s r e m o v e d , t h e h o l e s n e v e r b e i n g d e e p e n o u g h t o e x p o s e t h e t h o r a c i c 1 4 9 c a v i t y , r i b s o r l u n g s a s w a s o f t e n t h e c a s e w i t h a l b a t r o s s e s ( K e p l e r , 1 9 6 7 ) . I n 1 9 6 6 s e v e r a l p u s i l l a c h i c k s o f s e a -g o i n g a g e w e r e f o u n d d e a d o n t h e n e s t i n g s l o p e ; e x a m i n a t i o n s h o w e d w o u n d s l i k e t h o s e d e s c r i b e d a b o v e . I t w a s t h o u g h t t h a t t h e w o u n d s w e r e i n f l i c t e d a f t e r t h e c h i c k s h a d d i e d d u e t o o t h e r c a u s e s b u t s u b s e q u e n t o b s e r v a t i o n s o f l i v e c h i c k s w i t h w o u n d s s h o w e d t h i s t o b e n o t e n t i r e l y t r u e . W h i l e s t u d y i n g g r o w t h o f a u k l e t c h i c k s i n 1 9 6 7 t w o p s i t t a c u l a c h i c k s w e r e f o u n d w i t h t h e s e c h a r a c t e r i s t i c w o u n d s ; o n e w a s i n f l i c t e d o n 2 9 A u g u s t w h e n i t w a s 3 1 d a y s o l d a n d t h e o t h e r o n 1 S p e t e m b e r w h e n i t w a s 2 9 d a y s o f a g e ( f i g u r e 2 8 ) . When a u k l e t c h i c k s w e r e d i s t r u b e d b y me t h e y c h a r a c t e r i s t i c a l l y n e s t l e d i n t o a c o r n e r o f t h e n e s t - , s i t e l e a v i n g o n l y t h e i r d o r s a l s u r f a c e s e x p o s e d . I f e e l t h a t a s i m i l a r p o s t u r e w o u l d b e e l i c i t e d w h e n a v o l e e n t e r e d a n a c t i v e n e s t - s i t e , t h u s e n a b l i n g t h e r o d e n t t o c h e w o n t h e a u k l e t ' s d o r s a l s u r f a c e . On 13 J u n e 1 9 6 7 a n a d u l t A. c r i s t a t e l l a w a s n e t t e d b y E s k i m o s a n d l e f t o n t h e g r o u n d n e a r a t e n t a m i d t h e a u k l e t n e s t i n g c o l o n y . On 14 J u n e a t 0 3 0 0 h r I o b s e r v e d a r e d - b a c k e d v o l e f e e d i n g o n t h e a u k l e t . I t f e d f o r a b o u t 15 m i n u t e s b e f o r e l e a v i n g . On 19 J u n e I w i t n e s s e d a n e n c o u n t e r b e t w e e n a M i c r o t u s a n d a n a d u l t A. p u s i l l a w h i c h r e s u l t e d i n t h e v o l e b i t i n g t h e a u k l e t ' s s h o u l d e r a n d s e v e r i n g a m u s c l e w h i c h r e n d e r e d t h e a u k l e t f l i g h t l e s s . T h e b i r d , a n a d u l t m a l e , w e i g h e d 9 3 . 2 g a n d s h o w e d e x t e n s i v e 1 5 0 L e g e n d f o r F i g u r e 28 P a r a k e e t A u k l e t c h i c k , 2 9 d a y s o l d , 1 S e p t e m b e r 1 9 6 7 . N o t e w o u n d o n i t s b a c k . L e g e n d f o r F i g u r e 2 9 L e a s t A u k l e t c h i c k , 2 8 d a y s o l d , 3 1 A u g u s t 1 9 6 7 . N o t e m u t i l a t e d c o n d i t i o n o f t h e l e f t e y e . 1 5 1 s u b c u t a n e o u s h e m m h o r a g e o n t h e b a c k n e a r t h e b a s e o f t h e n e c k . On 24 J u n e I f l u s h e d a C l e t h r i o n o m y s f r o m a n a d u l t A. p u s i l l a c a r c a s s w h i c h h a d b e e n n e a r l y c o m p l e t e l y c l e a n e d o f i t s m u s c u l a t u r e a n d v i s c e r a . T h e c a u s e o f d e a t h o f t h e a u k l e t w a s n o t k n o w n . No d i r e c t e n c o u n t e r s b e t w e e n t h e v o l e s a n d a d u l t _C. p s i t t a c u l a a n d A. c r i s t a t e l l a w e r e o b s e r v e d . S e v e r a l e g g s o f e a c h s p e c i e s , p r e d o m i n a n t l y c r i s t a t e l l a a n d p u s i l l a / w e r e f o u n d w i t h l a r g e h o l e s a p p a r e n t l y c h e w e d b y r o d e n t s ; o n 1 8 J u l y 1 9 6 7 a C l e t h r i o n o m y s w a s o b s e r v e d f e e d i n g o n a l i v e e m b r y o i n a p i p p e d p u s i l l a e g g . M a n y c h i c k s , p r e d o m i n a n t l y L e a s t s , w e r e f o u n d d e a d s h o r t l y a f t e r t h e y h a d h a t c h e d w i t h t o o t h m a r k s o n t h e i r f l a n k s a n d p a r t l y e a t e n , u s u a l l y t h e i r h e a d a n d b r a i n b u t o f t e n t h e i r w i n g s w e r e c h e w e d . One p u s i l l a c h i c k w h o s e l e f t e y e w a s d e s t r o y e d b y a v o l e o r v o l e s w h e n t h e c h i c k w a s t w o d a y s o l d , l i v e d u n t i l i t w a s 2 8 d a y s o l d ( f i g u r e 2 9 ) . U t i l i z a t i o n o f b i r d s b y S t . L a w r e n c e I s l a n d E s k i m o s h a s b e e n d i s c u s s e d b y F a y a n d C a d e ( 1 9 5 9 ) a n d H u g h e s ( 1 9 6 0 ) . 152 CHAPTER V. Molt of Ad u l t s and J u v e n i l e s The molt of Cychlorrhynchus and A e t h i a spp. on St. Lawrence I s l a n d was stu d i e d by Bedard (1967; unpublished data). I t w i l l s u f f i c e here to summarize b r i e f l y the b a s i c molt patterns of the breeders showing t h e i r r e l a t i o n s to the breeding c y c l e s . Upon a r r i v a l at the breeding ground i n May, Cychlorrhynchus and most A e t h i a have completed t h e i r p r e n u p t i a l molt. The p o s t n u p t i a l molt of breeding Cychlorrhynchus and A e t h i a i s c h a r a c t e r i z e d by a gradual l o s s and replacement of p r i m a r i e s a few at a time, from the inner p r i m a r i e s outward, r a t h e r than the simultaneous l o s s and replacement t h a t occurs i n the l a r g e r f l y i n g a l c i d s , f o r example, Ur i a spp. (Tuck, 1961) and anatids (Kortwright, 1942) . Both genera.of a u k l e t s r e t a i n the outer p r i m a r i e s w h i l e molting the inner ones. The wing molt of A e t h i a spp. s t a r t e d about mid-July i n 1966 and 1967 followed by body molt beginning i n mid-August. The molt of non-breeders, not st u d i e d here, i s b r i e f l y discussed by Bedard (1967). Figures 30, 31 and 32 show the 1966 and 1967 schedules of breeding and molt i n Parakeet, Crested and Least a u k l e t s on St. Lawrence I s l a n d . I t i s i n t e r e s t i n g to note that the molt p a t t e r n of C. p s i t t a c u l a d i f f e r s from that of A e t h i a spp. i n that i t s p r e n u p t i a l 1 5 3 L e g e n d f o r F i g u r e 3 0 A g e n e r a l i z e d s u m m a r y o f b r e e d i n g a c t i v i t i e s a n d m o l t i n P a r a k e e t A u k l e t s o n S t . L a w r e n c e I s l a n d i n 1 9 6 6 a n d 1 9 6 7 . June July August September ^ estimated 1 5 4 L e g e n d f o r F i g u r e 3 1 A g e n e r a l i z e d s u m m a r y o f b r e e d i n g a c t i v i t i e s a n d m o l t i n C r e s t e d A u k l e t s o n S t . L a w r e n c e I s l a n d i n 1 9 6 6 a n d 1 9 6 7 . molt arrival of adults on slope 1966 post - breeding departure of adults growth of young egg-laying •m. I hatching sea-going of A*,,, chicks I Aethia c r is ta te l l a molt arrival of adults on slope 1967 post-breeding departure of adults growth of young I egg-laying hatching sea-going of chicks June July August September 1 5 5 L e g e n d f o r F i g u r e 3 2 A g e n e r a l i z e d s u m m a r y o f b r e e d i n g a c t i v i t i e s a n d m o l t i n L e a s t A u k l e t s o n S t . L a w r e n c e I s l a n d i n 1 9 6 6 a n d 1 9 6 7 . mol t a r r i v a l of a d u l t s on s lope 1966 p o s t - b r e e d i n g depar tu re of adu l t s /A growth of young I l k e g g - l a y i n g hatching s e a - g o i n g of ch icks Aethia pusil la -molt a r r i v a l of a d u l t s on s lope 1967 post -b reed ing depar tu re of a d u l t s | I growth of young e g g - l a y i n g hatching Ilk. of c h i c k s June July August September 156 m o l t o c c u r s p r i o r t o a r r i v a l o n t h e n e s t i n g s l o p e a n d i t s p o s t n u p t i a l m o l t c o m m e n c e s i n e a r l y S e p t e m b e r a f t e r t h e i r c h i c k s a r e r e a r e d . T h e r e i s t h u s , p a r t i a l o v e r l a p b e t w e e n b r e e d i n g a n d m o l t i n A e t h i a s p p . b u t a l m o s t n o n e i n C y c h l o r r h y n c h u s . A s a ' r e s u l t o f t h e p o s t n a t a l m o l t , y o u n g a u k l e t s a c q u i r e t h e i r f i r s t f e a t h e r c o v e r i n g , t h e J u v e n a l p l u m a g e . A l t h o u g h t h e s e s p e c i e s a r e c o m p l e t e l y c o v e r e d w i t h f e a t h e r s ( p r i m a r i e s a r e a b o u t 9 0 % o f t h e a d u l t l e n g t h a t f l e d g i n g ) w h e n t h e y l e a v e t h e n e s t , f e a t h e r g r o w t h p r o b a b l y c o n t i n u e s a f t e r f l e d g i n g b u t i t i s n o t k n o w n f o r h o w l o n g . T h e l a s t t r a c e s o f p o s t n a t a l m o l t r e m a i n o n t h e d o r s a l p o r t i o n o f t h e d o r s a l t r a c t , t h e a x i l a r r e g i o n , t h e p o s t - v e n t r a l r e g i o n a n d t h e c e r v i c a l r e g i o n . CHAPTER V I . T i m i n g o f t h e B r e e d i n g C y c l e s i n N o r t h B e r i n g Sea A u k l e t s From t h e f o r e g o i n g e x a m i n a t i o n o f ev e n t s i n t h e a n n u a l c y c l e s o f C y c h l o r r h y n c h u s p s i t t a c u l a , A e t h i a  c r i s t a t e l l a and A. p u s i l l a i n t h e n o r t h B e r i n g Sea, i t i s e v i d e n t t h a t (1) from t h e s p a r s e d a t a a v a i l a b l e , C. p s i t t a c u l a appears t o have a more e x t e n s i v e m i g r a t i o n t h a n A e t h i a (2) a r r i v a l o f a d u l t s o f b o t h genera back on t h e b r e e d i n g grounds i n s p r i n g o c c u r s a p p r o x i m a t e l y mid-May each y e a r , (3) t h e pre-egg s t a g e i s p r o l o n g e d b u t t h e p o s t - b r e e d i n g d i s p e r s a l o f a d u l t s and young from t h e n e s t i n g s l o p e i s r a p i d , (4) b r e e d i n g does n o t t a k e p l a c e a t t h e same t i m e each y e a r , (5) C y c h l o r r h y n c h u s b r e e d s a few days l a t e r than A e t h i a spp., (6) a r e m a r k a b l e change i n d i e t accompanies t h e on s e t o f t h e c h i c k - r e a r i n g p e r i o d i n A e t h i a spp. b u t n o t i n C y c h l o r r h y n c h u s , (7) p a t t e r n s and r a t e s o f growth o f c h i c k s d i f f e r a p p a r e n t l y a c c o r d i n g t o t i m e o f h a t c h i n g , (8) t h e c h i c k s appear t o be w e l l - a d a p t e d t o e a r l y l i f e , (9) p r e d a t i o n i s low i n t h e Sevuokuk c o l o n y , and (10) mol t o f a d u l t s o v e r l a p s t h e b r e e d i n g e f f o r t i n A e t h i a spp. b u t n o t i n C y c h l o r r h y n c h u s . E c o l o g i c a l and b e h a v i o r a l s p e c i a l i z a t i o n s i n t h e a n n u a l c y c l e s o f t h e s e a u k l e t s r e v e a l c e r t a i n a d a p t i v e 158 a d j u s t m e n t s t o t h e a r c t i c e n v i r o n m e n t , p a r t i c u l a r l y t o t h e s h o r t s u mmer. D e p e n d i n g u p o n t h e p h e n o l o g y o f t h e p a r t i c u l a r y e a r , summer o n S t . L a w r e n c e I s l a n d l a s t s f r o m a b o u t t h e m i d d l e o f J u n e t o e a r l y S e p t e m b e r . F r o m a c u r s o r y e x a m i n a t i o n o f t h e b r e e d i n g b i o l o g y o f t h e s e s p e c i e s i t a p p e a r s t h a t t h e y a r e f a c e d w i t h t w o p r o b l e m s i n t i m i n g t h e i r c y c l e s . B r e e d i n g m u s t t a k e p l a c e w i t h i n a p e r i o d w h i c h i s l a r g e l y d i c t a t e d b y c l i m a t e a n d t h e y m u s t m a k e b e s t u s e o f t h e f o o d s u p p l y a s i t n o r m a l l y o c c u r s i n t h a t p e r i o d . I n t h e d i s c u s s i o n t h a t f o l l o w s I s h a l l l o o k a t t h e u l t i m a t e a n d p r o x i m a t e f a c t o r s w h i c h a p p e a r t o b e i m p o r t a n t i n t i m i n g o f a u k l e t s ' b r e e d i n g c y c l e s o n S t . L a w r e n c e I s l a n d . A. U l t i m a t e F a c t o r s a . N e s t i n g S i t e s T h e a v a i l a b i l i t y o f n e s t i n g s i t e s i s d i r e c t l y i n f l u e n c e d b y a i r t e m p e r a t u r e s i n s p r i n g . A u k l e t s a r r i v e b a c k i n t h e w a t e r s p r o x i m a l t o t h e i r b r e e d i n g g r o u n d s a b o u t t h e m i d d l e o f M a y a n d r e t u r n t o t h e s n o w - c o v e r e d n e s t i n g s l o p e s a f e w d a y s l a t e r . I t i s o b v i o u s t h a t b r e e d i n g a n d n e s t i n g c a n n o t p r o c e e d w h e n s n o w s t i l l c o v e r s t h e n e s t - s t i e s . M e a n w h i l e t h e a u k l e t s p a i r r a p i d l y , w i t h i n a b o u t a w e e k o r s o a f t e r t h e i r r e t u r n t o t h e n e s t i n g s l o p e . I n 1 9 6 6 a n d 1 9 6 7 s n o w m e l t f r o m t h e s l o p e a n d t h e c o n s e q u e n t a v a i l a b i l i t y n e s t - s i t e s d i f f e r e d ; 1 9 6 7 1 5 9 w a s a n e a r l y s p r i n g w h i l e t h e 1 9 6 6 s p r i n g w a s l a t e . C o r r e s p o n d i n g l y , t h e d u r a t i o n o f t h e p r e - e g g s t a g e w a s l o n g e r ( a b o u t 3 0 d a y s ) i n 1 9 6 6 a n d s h o r t e r ( a b o u t 20 d a y s ) i n 1 9 6 7 . H o w e v e r , i n b o t h y e a r s t h e f i r s t e g g s ( p u s i l l a ) w e r e f o u n d a b o u t 1 0 d a y s a f t e r t h e s n o w d i s a p p e a r e d a n d n e s t c r e v i c e s b e c a m e a v a i l a b l e . W h a t t h e n " t r i g g e r s " t h e r e p r o d u c t i v e p r o c e s s e s t o f u n c t i o n a t p r e c i s e l y t h e p r o p e r t i m e i n a s e a s o n w h i c h m a y b e l a t e r o r e a r l i e r t h a n t h e p r e v i o u s y e a r ? G o n a d a l m a t u r a t i o n , m a t i n g a n d e g g - l a y i n g p r i o r t o s n o w m e l t i s o b v i o u s l y d i s a d v a n t a g e o u s t o t h e p o p u l a t i o n , w h i c h w a s t h e c a s e i n 1 9 6 7 w h e r e many a u k l e t s f a i t h f u l t o p o r t i o n s o f t h e t a l u s s l o p e o n t h e r i m o f t h e M o u n t a i n l a i d t h e i r e g g s o n t h e s n o w . T h e r e m a i n d e r o f t h e b r e e d i n g p o p u l a t i o n w a s a l r e a d y l a y i n g e g g s a n d i n c u b a t i n g o n t h e s n o w - f r e e r e a c h e s l o w e r o n t h e s l o p e . B a r r y ( 1 9 6 2 ) d e m o n s t r a t e d t h e e f f e c t s o f l a t e s e a s o n s o n B r a n t a w h e r e f e w e r y o u n g a r e p r o d u c e d i n some s e a s o n s t h a n i n o t h e r s . B r a n t , w h i c h a r r i v e o n t h e i r b r e e d i n g g r o u n d s o n t h e s a m e d a t e e a c h y e a r , m u s t a l s o w a i t f o r t h e s n o w t o m e l t a n d u n c o v e r n e s t i n g s i t e s . I f t h e s n o w p e r s i s t s , f o l l i c u l a r a t r e s i a r e s u l t s a n d n o e g g s w i l l b e l a i d i f s n o w m e l t i s e x c e p t i o n a l l y r e t a r d e d . F o l l i c u l a r a t r e s i a w a s n o t o b s e r v e d i n " s n o w -s i t t i n g " a u k l e t s d e s p i t e a d e q u a t e s a m p l i n g ; i n s t e a d t h e e g g s w e r e p r o d u c e d a n d l a i d o n t h e s n o w . F o o d , c o v e r e d b y s n o w a n d c o n s e q u e n t l y u n a v a i l a b l e t o B r a n t , w a s c o n s i d e r e d 160 to be one p o s s i b l e cause of a t r e s i a i n l a t e seasons (Barry, 1962); however, a u k l e t s feed at sea and thus can apparently o b t a i n the necessary energy to produce and maintain mature ova. Lack (1933) found t h a t A r c t i c Terns (Sterna macrura) i n northern Norway l a i d t h e i r eggs at d i f f e r e n t dates i n d i f f e r e n t areas as they s u c c e s s i v e l y became a v a i l a b l e a f t e r snow-melt. He suggested that the delayed a v a i l a b i l i t y of n e s t - s i t e s and the f a i l u r e of gonads to remain i n breeding c o n d i t i o n may combine to make reproduction impossible i n a p a r t i c u l a r year. This s i t u a t i o n i s a l s o i n c o n t r a s t to t h a t shown by the a u k l e t s which appear unable to h a l t t h e i r r e p r o d u c t i v e e f f o r t . Considering Cychlorrhynchus we see that i t s breeding c y c l e i s a few days l a t e r than those of A e t h i a spp. ( f i g u r e s 30, 31 and 32) even though Parakeets are the f i r s t to r e t u r n i n s p r i n g (table 5) . The reason f o r t h i s i s not obvious f o r , as w i l l be seen l a t e r , there i s no apparent adjustment to a food source d u r i n g c h i c k - r e a r i n g . The d i s t r i b u t i o n of n e s t i n g Parakeets at l e a s t i n the -Sevuokuk colony where t h i s species l a r g e l y u t i l i z e s the t a l u s slope f o r n e s t i n g may shed some l i g h t on t h i s problem. S p l i n t e r e d parent rock, which i s l o c a t e d p r i m a r i l y along the rim of the Mountain, provides Parakeets w i t h n e s t i n g s i t e s . I t i s a l s o along the r i m that the g r e a t e s t accumulation of snow occurs ( f i g u r e s 33 and 34) and 1 6 1 Cj L e g e n d f o r F i g u r e 33 N o r t h e a s t s l o p e o f S e v u o k u k M o u n t a i n s h o w i n g a c c u m u l a t i o n o f s n o w o n b r o w o f t h e M o u n t a i n , 5 J u n e 1 9 6 7 . L e g e n d f o r F i g u r e 34 C l o s e - u p v i e w o f b r o w o f n o r t h e a s t s l o p e o f S e v u o k u k M o u n t a i n s h o w i n g a c c u m u l a t i o n o f s n o w , 5 J u n e 1 9 6 7 . T a l u s s l o p e c o v e r e d b y t h e s e s n o w d r i f t s w a s u t i l i z e d f o r n e s t i n g b y s e v e r a l p a i r s o f P a r a k e e t A u k l e t s . 162 remains l a t e s t i n s p r i n g ( f i g u r e 6). By breeding l a t e r Cych1orrhyn chu s i s able to u t i l i z e these p o t e n t i a l n e s t - s i t e s that were u n a v a i l a b l e to them a week or so e a r l i e r when A e t h i a spp. commenced egg-laying; i n 196 7 only A e t h i a eggs were found on the snow even though s e v e r a l Parakeets were f a i t h f u l , i n some instances, to the same snow-covered h a b i t a t at the rim. b. Food and i t s a v a i l a b i l i t y The u l t i m a t e importance of food i n r e g u l a t i n g breeding seasons has been discussed by Lack (1954; 1966) and has been examined f o r many b i r d populations, mostly passerines at temperate and lower l a t i t u d e s (Lack, 1954; Dunnet, 1955; Snow, 1962, 1964; and o t h e r s ) . Lack's hypothesis has been supported by P i t e l k a (1959) and Holmes (1966) who worked on a r c t i c breeding shorebirds. The remarkable change i n d i e t that accompanies the s t a r t of the c h i c k - r e a r i n g p e r i o d i n A e t h i a spp. prompted Bedard (1967) to point out that t h e i r n e s t l i n g p e r i o d has been p o s s i b l y adjusted to the per i o d of maximum a v a i l a b l e energy i n the form of food. Indeed, as summarized from Bedard i n Chapter I I I t h i s s h i f t from a pblyphagous d i e t of zooplankters to a monophagous d i e t ( f i g u r e s 17 and 18) does not appear to be f o r t u i t o u s . The p o s s i b i l i t y that t h i s s h i f t i n d i e t r e f l e c t s a b e h a v i o r a l change i n the a d u l t s was considered but weakly supported 163 by Bedard. From the few data a v a i l a b l e on abundance of . prey throughout the summer i n surrounding waters, he f e e l s t h a t t h i s sharp r e v e r s a l to monophagy by A e t h i a apparently r e f l e c t s a sudden increase i n the a v a i l a b i l i t y of these prey items i n these waters. . When co n s i d e r i n g t h a t t i m i n g of a s p e c i e s ' breeding c y c l e has been adjusted so that i t can b e n e f i t from an increase i n the food supply i m p l i e s that l a b i l i t y i n t i m i n g of the breeding season i s p o s s i b l e . Holmes (1966) demonstrated t h a t a v a i l a b i l i t y of snow-free tundra d i d not appear to r e g u l a t e the onset of breeding i n Red-backed Sandpipers ( E r o l i a alpina) near Barrow, Alaska, but instead, the seasonal peak i n food supply ( l a r g e l y Dipterous i n s e c t s ) seemed important. Bedard (1967) pointed out that a s i m i l a r s i t u a t i o n e x i s t s i n a u k l e t s who spend as much as f i v e weeks on the breeding grounds before l a y i n g . He s t a t e d (p. 64-66) th a t "In p a r t i c u l a r l y good springs (1964), the n e s t - s i t e s are f r e e from snow and i c e two to three weeks e a r l i e r than the a c t u a l l a y i n g date. The b i r d s i n f a c t seem to breed at the l a t e s t p o s s i b l e time i n the study area". Observations on egg-laying i n r e l a t i o n to snow-melt i n t h i s study do not bear t h i s out e n t i r e l y . I t was found that the eggs were l a i d soon a f t e r the snow melted; about 10 days a f t e r snow-melt i n 1966 and 1967 d e s p i t e d i f f e r e n c e s i n t h e i r phenology. I have no data on year t o year abundance or t i m i n g of plankton "blooms" 164 i n t h i s area which might suggest that an e a r l y s p r i n g on a landmass might be accompanied by a correspondingly e a r l y " s p r i n g " i n the surrounding waters. The s i t u a t i o n regarding Cychlorrhynchus i s d i f f e r e n t ; i t does not appear to b e n e f i t d i r e c t l y from the increase, i n August, of Calanus and/or of Thysanoessa (Bedard, 1967), unless as Bedard pointed out, i t may b e n e f i t i n d i r e c t l y from the increase s i n c e the increase i n plankton biomass at t h a t time probably means an increase i n the same waters of predatory organisms which Parakeets predominantly feed. When c o n s i d e r i n g breeding c y c l e s of b i r d s , i t i s e q u a l l y important to examine t h e i r t e r m i n a t i o n as w e l l as onset and the f a c t o r s which determine these. We have seen t h a t a u k l e t s cannot l a y t h e i r eggs u n t i l the n e s t i n g c r e v i c e s are f r e e of snow i n June but why do they not extend t h e i r breeding u n t i l October? Table 2 shows that s n o w f a l l does not normally occur i n appreciable amounts u n t i l October; i n f a c t , u s u a l l y toward the end of October (L. Kulukhon, personal communication) and sea-ice does not form i n the surrounding waters u n t i l l a t e November (Fay and Cade, 1959) . Thus, n e s t i n g h a b i t a t i s a v a i l a b l e f o r about four months but i s u t i l i z e d f o r only about two and one-half months. The abrupt exodus of auklets from the n e s t i n g slope i s no doubt due at l e a s t i n part to the food supply. Bedard (1967) found that prey items 165 u t i l i z e d by A e t h i a were abundant during c h i c k - r e a r i n g but disappeared q u i c k l y from the a c c e s s i b l e l a y e r s (at l e a s t Calanus) i n e a r l y September. Why Cychlorrhynchus terminates i t s breeding c y c l e s h o r t l y a f t e r A e t h i a i s not apparent because i t does not r e l y , on prey species which o s c i l l a t e i n abundance. However, si n c e they feed on a higher t r o p h i c l e v e l , Parakeets take more carnivorous prey which may disappear when t h e i r prey disappears i n September. According t o Shuntov (1965), food items i n oceans are a f f e c t e d by c l i m a t e and the h y d r o l o g i c a l regime. Vinogradov (in Shuntov, 1965) s t a t e d that the main bulk of zooplankton i n winter i n the Bering Sea descends below the boundary of the win t e r - c o n v e c t i o n (200m) and i t s biomass i n the surface l a y e r decreases g r e a t l y . Thus, A e t h i a which feed on marine i n v e r t e b r a t e s obtained not f a r below the surface of the water would be unable to u t i l i z e prey now which was a c c e s s i b l e to them e a r l i e r . Breeding a c t i v i t y of Ptychoramphus a l e u t i c a on the F a r a l l o n e Islands, C a l i f o r n i a , spans the pe r i o d March t o October (Payne, 1965; Thoresen, 1964); i n other words, over a pe r i o d of about ei g h t months. This i s no doubt due to the extended p e r i o d of prey abundance i n the southern waters of i t s breeding range; Payne's study (1965) weakly supports t h i s assumption. 166 B e f o r e i t c a n b e s h o w n w i t h c e r t a i n t y t h a t t h e b r e e d i n g c y c l e s o f C y c h l o r r h y n c h u s a n d A e t h i a s p p . o n S t . L a w r e n c e I s l a n d h a v e b e e n a d j u s t e d t o t h e s e a s o n a l a b u n d a n c e o f f o o d , i t i s n e c e s s a r y t o a d e q u a t e l y s a m p l e a n d c e n s u s t h e p r e y b i o m a s s t h r o u g h o u t m a n y b r e e d i n g s e a s o n s a n d p r e f e r a b l y i n l o c a l i t i e s t h r o u g h o u t t h e i r b r e e d i n g r a n g e s . A t p r e s e n t i t c a n o n l y b e s a i d t h a t t h e c y c l i c a b u n d a n c e o f f o o d o r g a n i s m s may i n f l u e n c e t h e c o a r s e s e a s o n a l a d j u s t m e n t o f b r e e d i n g i n t h e s p e c i e s ( B e d a r d , p e r s o n a l c o r r e s p o n d e n c e ; t h i s s t u d y ) . B. P r o x i m a t e F a c t o r s a . T e m p e r a t u r e d u r i n g t h e p r e - e g g s t a g e M a n y a u t h o r s c l a i m t h a t a n i n c r e a s e i n a i r t e m p e r a t u r e s s t i m u l a t e s e g g - l a y i n g , b u t t h i s i s p r o v e n f o r f e w b i r d s i n n a t u r e . I f e e l t h a t n o o n e w o u l d d e n y t h e i m p o r t a n c e o f a i r t e m p e r a t u r e a n d i t s r i s e i n s p r i n g o n a r c t i c b r e e d i n g s e a - b i r d s . F i r s t l y , l o w t e m p e r a t u r e s i n w i n t e r c a u s e t h e o c e a n t o f r e e z e o v e r w h i c h r e n d e r s f o o d i n a c c e s s i b l e t o a u k l e t s , a t l e a s t a r o u n d S t . L a w r e n c e I s l a n d . U p o n t h e o n s e t o f w a r m e r w e a t h e r i n s p r i n g t h e i c e m e l t s ; f o o d i s n o w a c c e s s i b l e t o t h e m . S e c o n d l y , t h e p r e s e n c e a n d p e r s i s t e n c e o f s n o w - c o v e r o n t h e n e s t i n g s l o p e s , w h i c h c o v e r s n e s t - s i t e s , i s g o v e r n e d b y a i r t e m p e r a t u r e s ; e a r l y s e a s o n s l i k e 1 9 6 7 r e s u l t f r o m a n e a r l i e r o n s e t o f s p r i n g t e m p e r a t u r e s , e t c . I n d e e d , a i r t e m p e r a t u r e s 1 6 7 i n s p r i n g a r e o f i n d i r e c t i m p o r t a n c e i n i n i t i a t i n g b r e e d i n g b y a u k l e t s o n S t . L a w r e n c e I s l a n d f o r i t c a u s e s s n o w t o m e l t a n d t h u s p r o v i d e s a c c e s s t o n e s t i n g s i t e s . b . N e s t - s i t e s T h e a p p a r e n t i m p o r t a n c e o f n e s t i n g s i t e s a s a n u l t i m a t e f a c t o r i n a b i r d s p e c i e s ' b r e e d i n g i s o b v i o u s a n d d i s c u s s e d p r e v i o u s l y . I t a p p e a r s a l s o t h a t n e s t i n g s i t e s a c t a s p r o x i m a t e f a c t o r s , f a c t o r s i n t h e c h a n g i n g e n v i r o n m e n t t o w h i c h a n o r g a n i s m r e s p o n d s a n d w h i c h a c t a s t i m e r s o f t h e b r e e d i n g s e a s o n i n t h e p h y s i o l o g i c a l s e n s e ( S n o w a n d Snow, 1 9 6 4 ) . T h e a b s e n c e o f a n " e n v i r o n m e n t a l s t i m u l u s " ( M a r s h a l l , 1 9 5 4 ) p r o b a b l y r e t a r d s a u k l e t s 1 r e p r o d u c t i v e p r o c e s s e s w h e n t h e y f i n d t h e i r n e s t i n g g r o u n d s c o v e r e d w i t h s n o w o n a r r i v a l . A s t h e s n o w m e l t s , n e s t - s i t e s b e c o m e a v a i l a b l e t o " t r i g g e r " t h e b i r d s , w h i c h i n m a n y i n s t a n c e s l a i d t h e i r e g g s w i t h i n t w o o r t h r e e d a y s a f t e r t h e s n o w m e l t e d ( s e e C h a p t e r I ) . c . D a y - l e n g t h a n d i n t e r n a l f a c t o r s A c c o r d i n g t o M i l l e r ( 1 9 6 0 ) , f u l l r e p r o d u c t i v e c a p a c i t y o f a r c t i c b r e e d i n g b i r d s m u s t b e r e a c h e d s o m e w h a t i n a d v a n c e o f a c t u a l n e e d i n o r d e r t o i n s u r e r e a d i n e s s a n d a d j u s t m e n t t o y e a r t o y e a r v a r i a b l e s i n w e a t h e r a n d m e l t i n g s n o w c o v e r . T h e p r o x i m a t e s t i m u l u s o f t h i s r e c r u d e s c e n c e i n m a l e s m u s t b e c h i e f l y s o m e a s p e c t o f p h o t o p e r i o d , e i t h e r e a r l y o r m i d - w a y i n t h e s t a g e s . M i l l e r 168 also pointed out that t h i s fundamental contention, o r i g i n a l l y developed and in part tested by Rowan (1929), must stand generally v a l i d for high l a t i t u d e populations. Appendix I shows sunrise and sunset times for Nome, Alaska (about one degree north l a t i t u d e of St. Lawrence Island ); these data are s u f f i c i e n t l y comparable to the photoperiod which prevails on St. Lawrence Island. It i s seen that auklets breed with increasing daylight but laboratory studies have not been done to measure the effects of photoperiod on t h e i r gonad recrudescence. 1. The t e s t i s cycle in adult male auklets Figures 35 and 36 show the t e s t i s cycle in adult male A. p u s i l l a in 1966 and 1967, respectively, on St. Lawrence Island. It i s seen that gonads of males are somewhat advanced upon a r r i v a l as compared to those of resting size in late summer (August and September). It i s interesting to note that the average weight of l e f t testes in A. p u s i l l a may d i f f e r from year to year at the time of a r r i v a l on the nesting grounds; on 27 May of both years, t h i s weight was 0.121g in 1966 and 0.176g in 1967. In A. c r i s t a t e l l a t h i s weight was 0.445g in 1964, an early year (Bedard, personal correspondence), and 0.167g in 1966, a late year. It appears that gonads develop independently of conditions on the nesting ground at that time but the birds apparently are able 1 6 9 L e g e n d f o r F i g u r e 35 S e a s o n a l c h a n g e i n t e s t i s s i z e ( w e i g h t o f l e f t t e s t i s ) o f L e a s t A u k l e t s i n 1 9 6 6 . W e i g h t s i n c l u d e o n l y a d u l t m a l e s . 1 7 0 L e g e n d f o r F i g u r e 3 6 S e a s o n a l c h a n g e s i n t e s t i s s i z e ( w e i g h t s o f l e f t t e s t i s ) o f " s n o w - s i t t i n g " a n d " r o c k - s i t t i n g " L e a s t A u k l e t s i n 1 9 6 7 . W e i g h t s i n c l u d e o n l y a d u l t m a l e s . Left testis weight (centigrams) o — ro OJ J > c n o> b — ro '01 cn ai ~>i 4 — — i J i — — i i l 1 _J 1 i t i i I I OJ ~ O 171 t o " p r e d i c t " an oncoming e a r l y season and a r r i v e w i t h more advanced gonads i n such a year. They are thus capable of a c t i n g p h y s i o l o g i c a l l y to e a r l i e r appearing n e s t - s i t e s . T e s t i s weights i n adu l t " s n o w - s i t t i n g " versus " r o c k - s i t t i n g " A. p u s i l l a males are shown i n f i g u r e 36. I t was f e l t t hat those b i r d s c o u r t i n g and searching f o r nests under the rocks would be i n a more advanced stage of gonad development on a c e r t a i n date i n the pre-egg stage than those c o u r t i n g on the snow and presumably unaff e c t e d by v i s u a l s t i m u l i provided by the n e s t - s i t e s . This i s supported by data i n f i g u r e 36 but the sample s i z e i s inadequate and f u r t h e r d i s c u s s i o n i s not warranted. H i s t o l g i c examination of t e s t e s of these groups would p o s s i b l y r e v e a l r e a l d i f f e r e n c e s i f any e x i s t . . C. A d d i t i o n a l Adaptations f o r Timing i n Auklets (1) The sense of l o c a t i o n e x h i b i t e d by these a u k l e t s enables them to e s t a b l i s h themselves on the snow-covered slope when they r e t u r n i n s p r i n g and thus c u r t a i l time involved searching f o r nests when the snow melts. N e s t - s i t e t e n a c i t y would apparently reduce i n t r a -s p e c i f i c competition f o r n e s t - s i t e s , and the segregation on the n e s t i n g slopes demonstrated by Bedard (1967) reduces i n t e r s p e c i f i c competition f o r nests. This i s i n c o n t r a s t to Brant and other a r c t i c breeding geese which, a s n e s t i n g h a b i t a t b e c o m e s a v a i l a b l e , c o m p e t e v i o l e n t l y f o r n e s t - s i t e s ( B a r r y , 1 9 6 2 ) . (2) P a t t e r s o n ( 1 9 6 5 ) s u g g e s t e d t h a t b o t h c o l o n i a l n e s t i n g a n d s y n c h r o n i z a t i o n o f e g g - l a y i n g h a v e a n a n t i -p r e d a t o r f u n c t i o n . K r u u k ( 1 9 6 4 ) f e l t t h a t s i n c e t h e t o t a l n u m b e r o f p r e d a t o r s i s p r o b a b l y l i m i t e d b y t h e a m o u n t o f a v a i l a b l e f o o d d u r i n g t h e r e s t o f t h e y e a r a n d b y i n t r a - s p e c i f i c a g g r e s s i o n , c o n c e n t r a t i o n o f B l a c k - h e a d e d G u l l n e s t s i n t o t h e s h o r t e s t p o s s i b l e t i m e w i l l r e d u c e t h e t o t a l l o s s e s o v e r t h e s e a s o n . I n t h e p r e s e n t s t u d y , p r e d a t i o n w a s f o u n d t o b e l o w a n d i t a p p e a r s u n l i k e l y t h a t a u k l e t s ' t i m i n g i s i n f l u e n c e d b y t h i s f a c t o r . (3) T h e a b i l i t y s h o w n b y t h e s e s p e c i e s t o m a i n t a i n n e a r l y a d u l t b o d y t e m p e r a t u r e s w i t h i n t h e f i r s t f e w d a y s o f l i f e e n a b l e s b o t h p a r e n t s t o f e e d t h e c h i c k d u r i n g t h e a p p a r e n t i n c r e a s i n g f o o d s u p p l y a t t h i s t i m e , a t l e a s t i n t h e c a s e o f A e t h i a . (4) I t a p p e a r s t h a t t h e s e a u k l e t s h a v e s h o r t e n e d t h e s t a g e s o f t h e i r b r e e d i n g c y c l e s i n a d a p t i n g t o t h e a r c t i c e n v i r o n m e n t . T h e i n c u b a t i o n a n d n e s t l i n g p e r i o d s o f P a r a k e e t s , C r e s t e d s a n d L e a s t s a r e a b o u t 35 d a y s i n t h e f o r m e r t w o s p e c i e s a n d a b o u t 3 0 d a y s i n t h e l a s t . C o n s i d e r i n g t h e t e m p e r a t e b r e e d i n g a u k l e t , P t y c h o r amphu s  a l e u t i c a , we f i n d t h a t i t h a s a n i n c u b a t i o n p e r i o d o f " a t l e a s t 3 7 d a y s " a n d a n e s t l i n g p e r i o d o f a b o u t s i x w e e k s ( T h o r e s e n , 1 9 6 4 ) . I t i s o f i n t e r e s t t o e x a m i n e 173 n e s t l i n g periods i n these species, p a r t i c u l a r l y A. pus i l i a where the sample s i z e i s l a r g e r , i n 1966 and 1967 (table 17) and according to the time of hatching i n 1966 (table 23) . From data a v a i l a b l e i t appears t h a t Crested and Least c h i c k s g e n e r a l l y remained i n t h e i r nests longer i n 1967. This appears to have r e s u l t e d from slower growth of c h i c k s i n 1967. (5) The d i f f e r e n t i a l p a t t e r n of growth shown by e a r l i e s t hatched c h i c k s i n 1966 compared to those hatched l a t e i n the same year r e v e a l s c e r t a i n p o s s i b l e adaptations to a l a t e season. Figures 22 and 23 show these growth p a t t e r n s . Chicks hatched e a r l y grew f a s t e r and assumed a greater body weight, p o s s i b l y through a greater d e p o s i t i o n of subcutaneous f a t , and departed f o r sea weighing more, and about three days o l d e r , than late-hatched c h i c k s . This d i f f e r e n t i a l growth p a t t e r n i n A. p u s i l l a r e s u l t e d i n a simultaneous departure time (about 30 August 1966); thus, those chicks hatched l a t e may a l s o e x p l o i t the apparently increased food supply at t h i s time. I have no information on p o s t - f l e d g i n g m o r t a l i t y i n these species which might r e v e a l d i f f e r e n c e s i n s u r v i v a l between these two groups. According to P e r r i n s (1966) , those Slender-b i l l e d Shearwaters (Puffinus p u f f i n u s ) which fledge e a r l y s u r v i v e b e t t e r than those which fledge l a t e r . H a r r i s (1966), however, found no c o r r e l a t i o n between any phase or r a t e of chick development and the l a y i n g date i n the same s p e c i e s . As H a r r i s p o i n t e d o u t , a p o s s i b l e c r i t i c a l f a c t o r i n f l u e n c i n g t h e p r o d u c t i o n o f young w h i c h w i l l s u r v i v e t o j o i n t h e b r e e d i n g p o p u l a t i o n i s n o t t h e a v a i l a b i l i t y o f food d u r i n g t h e b r e e d i n g season b u t t h e s u c c e s s o f t h e young i n f i n d i n g f o o d a f t e r l e a v i n g t h e c o l o n i e s . He s a i d t h a t i f t h e r e was p l e n t y o f food a v a i l a b l e when t h e f i r s t c h i c k s l e a v e t h e y c o u l d l e a r n t o f e e d e c o n o m i c a l l y , whereas, l a t e r c h i c k s might p e r i s h when food became s h o r t because t h e y had l e s s o p p o r t u n i t y t o l e a r n . (6) B r e e d i n g and m o l t o f most temperate l a n d - b i r d s a r e i n c o n g r u e n t w i t h r e s p e c t t o t h e i r o n set and d u r a t i o n . B oth appear t o be ti m e d t o t h e s e a s o n a l abundance o f foo d . Lack (1954) proposed t h a t t h e s e p a r a t i o n o f t h e s e e v e n t s o f t h e an n u a l c y c l e s u g g e s t s t h a t b o t h b r e e d i n g and m o l t a r e accompanied by i n c r e a s e d energy d r a i n s on t h e b i r d s . S i m i l a r c o n t r o l s a r e thought by many o b s e r v e r s t o r e g u l a t e t h e t i m i n g o f c y c l e s o f s e a - b i r d s , many o f w h i c h b r e e d and m o l t a t d i f f e r e n t t i m e s o f the y e a r (Ashmole, 1962, 1963; Bent, 1919; Dorward, 1963; Maher, 1962; Salomonsen, 1944; and o t h e r s ) . Compromises between t h e s e p a r a t e s c h e d u l e s , however, have been r e a c h e d i n o t h e r s ; some t r o p i c a l and a r c t i c b r e e d i n g s e a - b i r d s have o v e r l a p p i n g s c h e d u l e s (Dorward and Ashmole, 1963; J o h n s t o n , 1961; Maher, 1962). Payne (1965) documented o v e r l a p p i n g o f t h e s e s c h e d u l e s i n t h e C a s s i n A u k l e t i n a temperate l a t i t u d e 175 As shown e a r l i e r , there i s a p a r t i a l overlap between breeding and molt i n A e t h i a spp. but almost none i n Cychlorrhynchus. Looking at the feeding r e l a t i o n s h i p s of these species throughout the breeding season may shed some l i g h t on the d i f f e r e n t i a l t i m i n g o f these events i n t h e i r annual c y c l e s . (Bedard, 1967:84-85) f e l t that these molt patterns may p o s s i b l y be r e l a t e d t o d i f f e r e n c e s i n feeding h a b i t s and s t a t e s " I t seems advantageous f o r A e t h i a spp. to undertake molt during the c h i c k - r e a r i n g p e r i o d f o r , both species can o b t a i n d u r i n g the l a t t e r p a r t of the breeding season p r e f e r r e d foods i n apparently super-abundance. On the contrary, Cychlorrhynchus, whose mainstay i s not known to o s c i l l a t e so much i n a v a i l a b i l i t y , has the opportunity of spreading more evenly i t s necessary energy expenditure and as noted i n Chapter I, does not s t a r t molting u n t i l the very end of the c h i c k - r e a r i n g p e r i o d " . This explanation appears f e a s i b l e w i t h our present knowledge f o r i t i s thought t h a t p a r e n t a l care of eggs and young r a i s e s the food requirements of a d u l t b i r d s during the breeding season (Payne, 1965) and breeding a d u l t s must obta i n enough e x t r a food f o r the growth of the young as w e l l as f o r t h e i r own increased a c t i v i t y . T his appears to be what i s happening w i t h A e t h i a and Cychlorrhynchus. D. Summary of Timing The arguments o u t l i n e d i n t h i s chapter i n d i c a t e t h a t t h e p r o x i m a t e f a c t o r s a f f e c t i n g t h e o n s e t a n d c o u r s e o f t h e b r e e d i n g s e a s o n a r e o f p r i m a r y i m p o r t a n c e i n d i c t a t i n g t h e a n n u a l c y c l e s o f C y c h l o r r h y n c h u s a n d A e t h i a . T h e t i m i n g o b s e r v e d i n t h e s e s p e c i e s o n S t . L a w r e n c e I s l a n d , A l a s k a , i s s e e n t o b e a s e r i e s o f a d a p t i v e c o m p r o m i s e s r e l a t e d t o t h e s h o r t s e a s o n a v a i l a b l e f o r b r e e d i n g a n d t o t h e c y c l e o f c h a n g e i n t h e f o o d s u p p l y . 1 7 7 SUMMARY 1. C y c h l o r r h y n c h u s h a s a m o r e e x t e n s i v e m i g r a t i o n t h a n A e t h i a . 2. A r r i v a l o f a d u l t s o f P a r a k e e t , C r e s t e d , a n d L e a s t a u k l e t s o c c u r s a b o u t m i d - M a y e a c h y e a r o n S t . L a w r e n c e I s l a n d . 3. T h e p r e - e g g s t a g e o f P a r a k e e t , C r e s t e d , a n d L e a s t a u k l e t s o n S t . L a w r e n c e I s l a n d ( e x t e n d i n g f r o m t h e t i m e t h e b i r d s f i r s t c o m e a s h o r e a t t h e c o l o n y u n t i l t h e f i r s t e g g i s l a i d ) w a s a b o u t o n e m o n t h i n 1 9 6 6 a n d a b o u t t h r e e w e e k s i n 1 9 6 7 . 4. A t t h e t i m e o f a r r i v a l o f a d u l t a u k l e t s o n t h e c o l o n y i n s p r i n g t h e n e s t i n g s l o p e s a r e c o v e r e d w i t h v a r y i n g a m o u n t s o f s n o w . A d u l t s o f t h e t h r e e s p e c i e s o f a u k l e t s s e t t l e i n a n o n - r a n d o m f a s h i o n o n t h e s n o w a b o v e t h e i r f u t u r e n e s t - s i t e s . 5. A s s h o w n b y b a n d i n g , C r e s t e d a n d L e a s t a u k l e t p a i r s r e m a i n i n t a c t f o r m o r e t h a n o n e y e a r . 6. R e - u s e o f t h e n e s t - s i t e o f p r e v i o u s s e a s o n s a p p e a r s t o b e t h e r u l e i n e s t a b l i s h e d p a i r s . 7. C o p u l a t i o n o c c u r s a t s e a a n d o n t h e n e s t - s i t e . 8. N e s t - s i t e s i n t h e s e a u k l e t s a r e d e s c r i b e d ; f o u r m a i n t y p e s a r e u t i l i z e d b y P a r a k e e t s , t h r e e m a i n t y p e s b y C r e s t e d , a n d f i v e m a i n t y p e s a r e u t i l i z e d b y L e a s t s o n 1 7 8 S t . L a w r e n c e I s l a n d . N e s t - s i t e s a r e n a t u r a l l y f o r m e d c r e v i c e s a m o n g t h e b o u l d e r s o n t h e t a l u s s l o p e . No n e s t i n g m a t e r i a l i s u s e d . 9. O n s e t a n d p e a k o f e g g - l a y i n g i n A e t h i a s p p . w e r e s t u d i e d i n 1 9 6 6 a n d 1 9 6 7 a n d i n C y c h l o r r h y n c h u s i n 1 9 6 7 . E x t r e m e e a r l i e s t d a t e s f o r c l u t c h c o m m e n c e m e n t w e r e 1 4 J u n e a n d 4 J u l y i n A. c r i s t a t e l l a , 12 J u n e a n d 4 J u l y i n A. p u s i l l a a n d 2 1 J u n e i n C. p s i t t a c u l a . E g g - l a y i n g i n r e l a t i o n t o s n o w - m e l t i s d i s c u s s e d . 1 0 . E a c h s p e c i e s l a y s o n e e g g t o a c l u t c h . 1 1 . I n 1 9 6 7 , a n e a r l y y e a r , o n e i r r e f u t a b l e c a s e o f r e n e s t i n g i n C y c h l o r r h y n c h u s a n d t w o p o s s i b l e i n s t a n c e s o f r e n e s t i n g i n e a c h o f A. c r i s t a t e l l a a n d A. p u s i l l a w e r e r e c o r d e d . 1 2 . S t a t i s t i c s o n t h e p e r i o d f r o m l a y i n g t o h a t c h i n g a r e p r e s e n t e d . T h e " i n c u b a t i o n p e r i o d " o f C. p s i t t a c u l a w a s a b o u t 35 d a y s , o f A. c r i s t a t e l l a w a s a b o u t 35 d a y s a n d o f A. p u s i l l a w a s a b o u t 3 1 d a y s . 1 3 . I n c u b a t i o n t e m p e r a t u r e s i n t h e s e a u k l e t s w e r e m e a s u r e d w i t h t h e a i d o f t h e r m o c o u p l e s ; " s p o t " m e a s u r e m e n t s -w e r e t a k e n o f a d u l t b i r d s 1 b r o o d p a t c h e s w i t h i n 15 s e c o n d s a f t e r c a p t u r e b y h a n d o n t h e i r n e s t s . T e m p e r a t u r e s i n t h e n e s t - s i t e s w e r e r e l a t i v e l y c o n s t a n t , v a r y i n g w i t h i n a f e w d e g r e e s a r o u n d 11°C. ) 17S 1 4 . B r o o d p a t c h t e m p e r a t u r e s a v e r a g e d 3 6 . 9 c i i C. p s i t t a c u l a , 3 8 . 1 ° C i n A. c r i s t a t e l l a a n d 3 8 . 0 ° C i n A. p u s i l l a . 1 5 . B o t h s e x e s o f e a c h s p e c i e s i n c u b a t e . 1 6 . N e s t l i n g p e r i o d s i n t h e s e a u k l e t s a v e r a g e d 35 d a y s i n C. p s i t t a c u l a , 33 d a y s i n A. c r i s t a t e l l a a n d 2 9 d a y s i n A. p u s i l l a . 1 7 . G r o w t h i n b o d y w e i g h t a n d c e r t a i n b o d y p a r t s ( c u l m e n , r e c t r i x , o u t e r p r i m a r y , t a r s u s ) f r o m h a t c h i n g t o n e s t d e p a r t u r e w e r e s t u d i e d i n e a c h s p e c i e s . A t t h e t i m e o f s e a - g o i n g t h e j u v e n i l e s a v e r a g e d a b o u t 8 0 p e r c e n t o f t h e a d u l t s ' b o d y w e i g h t i n C. p s i t t a c u l a a n d A. c r i s t a t e l l a a n d a b o u t 85 p e r c e n t i n A. p u s i l l a . 1 8 . P a t t e r n s a n d r a t e s o f g r o w t h o f A. p u s i l l a c h i c k s a n d p o s s i b l y c h i c k s o f t h e o t h e r t w o s p e c i e s d i f f e r a c c o r d i n g t o t i m e o f h a t c h i n g . T h e n e s t l i n g p e r i o d i s s h o r t e r i n l a t e - h a t c h e d c h i c k s c o m p a r e d t o t h e n e s t l i n g p e r i o d o f e a r l y - h a t c h e d c h i c k s . 1 9 . T h e c h i c k s o f e a c h s p e c i e s a r e w e l l - a d a p t e d t o e a r l y l i f e . T h e r m o r e g u l a t i o n o f e s s e n t i a l l y a d u l t b o d y t e m p e r a t u r e s s e t s i n a t a b o u t t h r e e d a y s o f a g e i n C. p s i t t a c u l a a n d A. c r i s t a t e l l a a n d a t a b o u t f i v e d a y s o f a g e i n A. p u s i l l a . 2 0 . N e s t d e p a r t u r e w a s w i t n e s s e d s e v e r a l t i m e s i n 1 9 6 7 . 1 8 0 T h e g r e a t e r p r o p o r t i o n o f c h i c k s d e p a r t e d f o r s e a d u r i n g t h e e a r l y m o r n i n g h o u r s . 2 1 . P r e d a t i o n w a s l o w i n t h e S e v u o k u k c o l o n y ; m i c r o t i n e r o d e n t s w e r e m a i n l y r e s p o n s i b l e . 2 2 . M o l t o f a d u l t s o v e r l a p s t h e b r e e d i n g e f f o r t i n A e t h i a s p p . b u t n o t i n C y c h 1 o r r h y n c h u s. 2 3 . T h e i m p o r t a n c e o f t h e u l t i m a t e f a c t o r s , n e s t i n g s i t e s a n d f o o d f o r t h e y o u n g , i n t i m i n g o f t h e s e s p e c i e s ' b r e e d i n g c y c l e s o n t h i s I s l a n d a r e s t r e s s e d . 2 4 . T h e i m p o r t a n c e o f t e m p e r a t u r e , n e s t i n g s i t e s a n d p h o t o p e r i o d a s p r o x i m a t e i n f l u e n c e s o n i n i t i a t i o n o f b r e e d i n g a r e d i s c u s s e d . 2 5 . 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The b l a c k g u i l l e m o t s o f Kent I s l a n d , Bay o f Fundy, Auk, 67:129-15 2. Wynne-Edwards, V.C. 1955. Low r e p r o d u c t i v e r a t e s i n b i r d s , e s p e c i a l l y s e a - b i r d s . P r o c . XI I n t . O r n i t h . Congr., 540-547. 1962. A n i m a l d i s p e r s i o n i n r e l a t i o n t o s o c i a l b e h a v i o r . O l i v e r and Boyd, E d i n b u r g h . 193 Legend f o r Appendix I Sunrise and sunset times at Nome, Alaska. Bering Standard Time. Data from the N a u t i c a l Almanac O f f i c e , United States Naval Observatory (1959). DAY JAN. FEB. MAR. APR. MAY JUNE JULY AUG.. SEPT. OCT. NOV. DEC. Rise Set Rise Set Rise Set Rise Set Rise Set Rise Set Rise Set Rise Set. Rise Set Rise Set Rise Set Rise Set A.M. P.M. A.M. P.M. A.M. P.M. A.M. P.M. A.M. P.M. A.M. P.M. A.M. P.M. A.M. P.M. A.M. P.M. A.M. P.M. A.M. P.M. A.M. P.M. 1 9 59 2 12 8 45 3 47 7 11 5 19 5 19 6 54 3 32 8 28 1 50 10 11 1 30 10 39 3 04 9 09 4 42 7 19 6 11 5 31 7 47 3 43 9 25 2 16 2 9 58 2 14 8 42 3 50 7 07 5 22 5 16 6 57 3 28 8 32 1-48 10 14 1 33 10 37 3 08 9 06 4 45 7 15 6 14 5 27 7 50 3 39 9 28 2 14 3 9 57 2 16 8 39 3 54 7 04 5 25 5 12 7 00 3 25 8 35 1 45 10 17 1 35 10 35 3 11 9 02 4 48 7 12 6 17 5 23 7 54 3 36 9 30 2 12 4 9 56 2 18 8 36 3 57 7 00 5 28 5 09 7 03 3 21 8 38 1 42 10 20 1 37 10 33 3 14 8 59 4 51 7 08 6 19 5 20 7 57 3 33 9 33 2 11 5 .9 54 2 21 8 32 4 00 6 56 5 32 5 05 7 06 3 18 8 42 1 40 10 22 1 40 10 31 3 17 8 55 4 54 7 04 6 22 5 16 8 00 3 30 9 36 2 09 6 9 52 2 23 8 29 4 04 6 53 5 35 5 01 7 09 3 14 8 45 1 38 10 25 1 42 10 29 3 21 8 52 4 57 7 01 6 25 5 13 8 04 3 26 9 38 2 07 7 9 51 2 26 8 26 4 07 6 49 5 38 4 58 7 12 3 11 8 48 1 35 10 28 1 45 10 26 3 24 8 48 5 00 6 57 6 28 5 09 8 07 3 23 9 41 2 05 8 9 49 2 29 8 23 4 11 6 46 5 41 4 54 7 15 3 07 8 52 1 33 10 30 1 47 10 24 3 27 8 45 5 03 6 54 6 31 5 06 8 10 3 20 9 43 2 04 9 9 47 2 32 8 19 4 14 6 42 5 44 4 50 7 18 3 04 8 55 1 31 10 32 1 50 10 21 3 31 8 41 5 06 6 50 6 34 5 02 8 14 3 17 9 45 2 03 10 9 45 2 35 8 16 4 17 6 39 5 47 4 47 7 21 3 00 8 58 1 29 10 35 1 53 10 18 3 34 8 38 5 09 6 46 6 38 4 59 8 17 3 14 9 48 2 01 11 9 43 2 37 8 13 4 21 6 35 5 50 4 43 7 24 2 57 9 02 1 27 10 37 1 56 10 16 3 37 8 34 5 12 6 43 6 41 4 55 8 20 3 10 9 50 2 00 12 9 40 2 40 8 09 4 24 6 31 5 53 4 40 7 27 2 53 9 05 1 26 10 39 , 1 59 10 13 3 40 8 31 5 15 6 39 6 44 4 51 8 24 3 07 9 52 1 59 13 9 38 2 43 8 06 4 27 6 28 5 56 4 36 7 31 2 50 9 09 1 24 10 40 2 02 10 10 3 43 8 27 5 18 6 36 6 47 4 48 8 27 3 04 9 53 1 58 14 9 36 2 47 8 03 4 31 6 24 5 59 4 32 7 34 2 47 9 12 1 23 10 42 2 05 10 07 3 47 8 24 5 21 6 32 6 50 4 44 8 30 3 01 9 55 1 58 15 9 33 2 50 7 59 4 34 6 21 6 02 4 29 7 37 2 43 9 15 1 22 10 43 2 08 10 04 3 50 8 20 5 24 6 28 6 53 4 41 8 34 2 58 9 57 1 57 16 9 31" 2 53 7 56 4 37 6 17 6 05 4 25 7 40 2 40 9 19 1 21 10 45 2 12 10 01 3 53 8 17 5 27 6 25 6 56 4 37 8 37 2 55 9 58 1 57 17 9 28 2 56 7 52 4 41 6 14 6 08 4. 22 7 43 2 37 9 22 1 20 10 46 2 15 9 58 3 56 8 13 5 30 6 21 6 59 4 34 8 40 2 52 9 59 1 57 18 9 26 2 59 7 49 4 44 6 10 6 11 4 18 7 46 2 33 9 26 1 20 10 47 2 18 9 55 3 59 8 09 5 32 6 17 7 02 4 30 8 44 2 49 10 00 1 56 19 9 23 3 03 7 45 4 47 6 06 6 14 4 14 7 49 2 30 9 29 1 19 10 47 2 21 9 52 4 02 8 06 5 35 6 14 7 05 4 27 8 47 2 47 10 01 1 56 20 9 21 3 06 7 42 4 50 6 03 6 17 4 11 7 53 2 27 9 32 1 19 10 48 2 24 9 49 4 06 8 02 5 38 6 10 7 08 4 23 8 50 2 44 10 02 1 57 21 9 18 3 09 7 39 4 54 5 59 6 20 4 07 7 56 2 23 9 36 1 19 10 48 2 28 9 46 4 09 7 5.9 5 41 6 07 7 12 4 20 8 54 2 41 10 03 1 57 22 9 15 3 13 7 35 4 57 5 56 6 23 4 04 7 59 2 20 9 39 1 19 10 48 2 31 9 43 4 12 7 55 5 44 6 03 7 15 4 17 8 57 2 38 10 03 1 58 23 9 12 3 16 7 32 5 00 5 52 6 26 4 00 8 02 2 17 9 42 1 20 10 48 2 34 9 39 4 15 7 51 5 47 5 59 7 18 4 13 9 00 2 36 10 04 1 58 24 9 09 3 19 7 28 5 03 5 48 6 29 3 56 8 05 2 14 9 46 1 20 10 47 2 38 9 36 4 18 7 48 5 50 5 56 7 21 4 10 9 03 2 33 10 04 1 59 25 9 06 3 23 7 25 5 06 5 45 6 32 3 53 8 09 2 11 9 49 1 21 10 47 2 41 9 33 4 21 7 44 5 53 5 52 7 24 4 06 9 06 2 30 10 04 2 00 26 9 03 3 26 7 21 5 10 5 41 6 36 3 49 8 12 2 08 9 52 1 22 10 46 2 44 9 29 4 24 7 41 5 56 5 49 7 27 4 03 9 10 2 28 10 04 2 01 27 9 00 3 30 7 18 5 13 5 37 6 39 3 46 8 15 2 05 9 55 1 24 10 45 2 48 9 26 4 27 7 37 5 59 5 45 7 31 3 59 9 13 2 26 10 03 2 03 28 8 57 3 33 7 14 5 16 5 34 6 42 3 42 8 18 2 02 9 59 1 25 10 43 2 51 9 23 4 30 7 33 6 02 5 41 7 34 3 56 9 16 2 23 10 03 2 04 29 8 54 3 36 7 13 5 18 5 30 6 45 3 39 8 22 1 59 10 02 1 27 10 42 2 54 9 19 4 33 7 30 6 05 5 38 7 37 3 53 9 19 2 21 10 02 2 06 30 8 51 3 40 5 27 6 48 3 35 8 25 1 56 10 05 1 28 10 41 2 58 9 16 4 36 7 26 6 08 5 34 7 40 3 49 9 22 2 19 10 02 2 07 31 8 48 3 43 5 23 6 51 1 53 10 08 3 01 9 13 4 39 7 23 7 44 3 46 10 01 2 09 Add.one hour for Daylight Saving Time if and when in use. I certify that the above data are the result of an accurate and true com-putation by the Nautical Almanac Office, United States Naval Observatory, •. ' an agency charged by Federal Statute (9 Stat. L 374, 37.5) with the duty of making such computations and publishing the results. E. W. WOOLARD Director Nautical Almanac U. S. Naval Observatory • C. G. CHRISTIE Captain, USN Superintendent U. S. Naval Observatory 

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