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An ecological study of Goose Island, British Columbia, with special reference to terrestrial mammals Guiguet, Charles J. 1950

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u e s  Cap  6 7  <i  AN ECOLOGICAL STUDY OF GOOSE  ISLAND,  BRITISH COLUMBIA, WITH SPECIAL REFERENCE TO TERRESTRIAL MAMMALS  by Charles J . Gulguet  A Thesis  Submitted  in Partial  Fulfilment of  the Requirements f o r the Degree o f MASTER OF  ARTS  i n t h e Department of ZOOLOGY  THE  UNIVERSITY OF B R I T I S H COLUMBIA April,  1950  AN E C O L O G I C A L STUDY OF GOOSE I S L A N D , WITH S P E C I A L  BRITISH  R E F E R E N C E TO T E R R E S T R I A L  COLUMBIA,  MAMMALS  by  Charles  J . Guiguet  ABSTRACT A  study  o f mammals  islands represents  many o u t e r the  fringe  qualitative  undertaken the  Microtua bats  also  distribution  terrestrial  species  the coast.  Over and above  o f the fauna,  of terrestrial  mammalian  and Sorex  occurred,  represented  o f Caator  once  o f these  extent  the relative  species.  h a b i t a t s was d e t e r m i n e d  and nature  the islands.  a n d Sorex was  by a l l three  distributions  and Myotis  inhibited  on a snap t r a p p r o c e d u r e  four habitats occupied  manlculatus.  Two s p e c i e s o f  L a s l o n y c t e r l s noctivagans  A species  the observed  was  obscurus.  o f Peromyscus, Microtus  The  fauna  mammals.  o f s m a l l mammals, P e r o m y s c u s  longicaudus  composition for  examinations  typical of  upon  Based  in  islands along  unit  group  t o o b t a i n some q u a n t i t a t i v e i n f o r m a t i o n  yumanensis.  abundance  isolated  This  were  ecological  three  a well  British  studies  The by  Island,  i n t h e s u m m e r o f 19^8.  C o l u m b i a , was c o n d u c t e d of  on t h e Goose  and  determined The  floral  reasons  postulated. of eight  i n c l u d e d a s well  additional  habitats  have been  as notes  mammal8,  Myot i s . L a s l o n y c t e r l s a n d C a s t o r .  on p e l a g i c  TABLE OF CONTENTS INTRODUCTION  I  GEOLOGICAL BACKGROUND LOCATION AND  .  1  GENERAL DESCRIPTION...-  2  CLIMATE  -••  FLORAL ANALYSES  AND  6  DESCRIPTION OF HABITAT TYPES  Coniferous forest  8  -..  8  Muskeg., i  16  Meadow  <  20  Beach d e b r i s  23  Rocky s e a s h o r e . .  28  Boulder beach  32  Sandy s e a b e a c h  and t i d a l mud  flat  32  MAMMALIAN POPULATIONS. D i s c u s s i o n o f methods, p r o c e d u r e s  32 and a p p l i c a t i o n . . . . 3 2  O u t l i n e o f mammalian f a u n a . .  45  DISTRIBUTION OF SPECIES I N TERMS OF HABITAT Castor  46  sp  46  Lasionycteris noctivagans M y o t i s yumanensis Peromyscus m a n i c u l a t u s Microtus longicaudus Sorex obscurus Balaenoptera physalis Meg a p t e r a n o v a e a n g l i a e Phocoenoldes  dalli  "  46 46A .46A 46A .47 47 ...47 47  Eumetopias  jubata..  .  49  Callorhinus ursina..  49  Phoca v i t u l i n a  49  GENERAL DISCUSSION OF OBSERVED DISTRIBUTIONS OF TERRESTRIAL..MAMMALS Castor  canadensis.....  Lasionycteris  noctivagans  50 , . 50 50 53  M y o t i s yumanensis  53  Peromyscus m a n l c u l a t u s  56  Microtus longicaudus  64  Sorex  67  obscurus  THEORIES ON THE ORIGINAL OCCURRENCE OF INSULAR POPULATIONS  72  SUMMARY AND CONCLUSIONS  76  LITERATURE CITED  79  I  AN ECOLOGICAL STUDY OF  GOOSE ISLAND, BRITISH COLUMBIA,  WITH SPECIAL REFERENCE TO  TERRESTRIAL MAMMALS.  INTRODUCTION The  Goose I s l a n d s  mainland coast  lying  comprise  an  o f f the B r i t i s h  outer u n i t i n a  i n s u l a r p a t t e r n i n which g e o g r a p h i c a l water i n t e n s i f y The  g e n e r a l l y to  Columbia  complex  b a r r i e r s of  westwards.  group, i n i t s c e n t r a l l o c a t i o n , s m a l l s e l e c t e d i n 1948  field  the U n i v e r s i t y o f B r i t i s h  and  the  P r o v i n c i a l Museum.  constituted  the  field  I n view o f the  Mr.  party and  small  area  involved  t o make r e p r e s e n t a t i v e  mammalian f a u n a s , and  the  flora.  ing  specimens o f marine v e r t e b r a t e s  the  surrounding  waters.  a c c o m p l i s h e d what i t h a d  Columbia  and  s t u d y and  myself  and  t o do.  throughout the p e r i o d . Invertebrates  a representative  would  c o l l e c t i o n s of specimens  supplied for  the  field  Some 400  of  collect-  invertebrates  these respects  s e t out  thought  mammals were c o l l e c t e d , p r e p a r e d , and  o f m a r i n e f i s h e s and  made.  In  i t was  to gather  I n a d d i t i o n , e q u i p m e n t was  notes maintained  for  t h r o u g h August  avian  future  area  and  party.  the  o f b i r d s and  ah  Patrick Martin  t h a t f o u r months a l l o c a t e d f r o m May enable the  as  size  c o m p l e t e i s o l a t i o n was i n v e s t i g a t i o n by  salt  from party  specimens adequate  O v e r 1009 s p e c i m e n s  were a l s o c o l l e c t e d f o r collection of plants  was  II The at  f i e l d work was i n i t i a t e d  t h e end o f August.  examination  o n May 13 a n d t e r m i n a t e d  O v e r and above t h e q u a l i t a t i v e  o f the fauna,  s t u d i e s were u n d e r t a k e n  to obtain  some q u a n t i t a t i v e i n f o r m a t i o n u p o n t h e e c o l o g i c a l t r i b u t i o n o f t h e mammals a n d b i r d s .  dis-  To a c c o m p l i s h  this^  emphasis was p l a c e d u p o n t h e s m a l l mammal work i n May a n d J u n e i n o r d e r t o h a v e t h e raw d a t a c o l l e c t e d animals  o f t h e y e a r began t o run.  o p e r a t e only" f o u r quadrats  T h i s enabled us t o  i n each h a b i t a t  s m a l l mammals, b u t h a d t h e a d v a n t a g e adult  animals  except  revealed  occupied by  of dealing only with  i n t h e case o f Sorex  t h e y o u n g were a l r e a d y o u t .  b e f o r e young  obscurus,  where  Preliminary investigations  a n e q u a l amount o f s i g n i n t h e two t y p e s o f  coniferous  forest occurring.  F o r the purposes  of small  mammal s t u d y t h e s e t y p e s a r e i n c l u d e d u n d e r o n e h e a d i n g i n t h e mammal q u a d r a t work, a n d s e p a r a t e l y u n d e r  floral  analyses. T h i s paper  i s a presentation of the results  obtained  in  t h e mammalian s t u d i e s o n l y ; i t i n c l u d e s  the d i s t r i b u t i o n  of  habitat  by mammals.  types r e g a r d l e s s o f u t i l i z a t i o n  The m a j o r p r o b l e m  entails  the f l o r a l  analyses o f the  v e g e t a t e d h a b i t a t s o c c u p i e d b y s m a l l mammals, d e t e r m i n a t i o n of  relative  abundance o f t h e s e a n i m a l s  where p o s s i b l e , the observed part,  i n each h a b i t a t and,  the determination of factors  distributions.  While  responsible f o r  investigations  t o t h a t p r e s e n t e d h e r e have been c a r r i e d  similar In  o u t on t h e  Ill  mainland i n the eastern  part o f the continent  1 9 3 5 ) , t o my k n o w l e d g e no c o m p a r a b l e conducted on the P a c i f i c paper w i l l intensified  coast.  a c t as a f o r e r u n n e r studies  (Townsend,  s t u d i e s have been  I t i s hoped t h a t  this  t o more c o m p r e h e n s i v e a n d  on our c o a s t a l i s l a n d s .  I n acknowledgment I w i s h t o t h a n k D r . I . M c T a g g a r t Cowan, u n d e r whose d i r e c t i o n t h i s  research  was c o n d u c t e d ;  Dr.  W. A. C l e m e n s , Head o f t h e D e p a r t m e n t o f Z o o l o g y , a n d  Dr.  G. C. C a r l , D i r e c t o r o f t h e P r o v i n c i a l Museum, f o r  valuable  suggestions and cooperation;  P r o v i n c i a l Museum B o t a n i s t , Department o f B i o l o g y suggestions pertaining  Mr. George Hardy,  and D r . T. M. C. T a y l o r ,  and Botany, f o r i d e n t i f i c a t i o n s and to the f l o r a ;  f o r hours spent i n s t a t i s t i c a l  a n d D r . P. A. L a r k i n  analyses  and c r i t i c a l  examination o f the data. In  a d d i t i o n I w i s h t o t h a n k M r . P. w. M a r t i n  invaluable  assistance  i n the f i e l d ,  for his  and t h e s e c r e t a r i a l  s t a f f o f t h e P r o v i n c i a l Museum f o r t e c h n i c a l a s s i s t a n c e i n preparation I Affairs  of the manuscript.  am e s p e c i a l l y i n d e b t e d  t o t h e Department o f V e t e r a n s '  f o r t h e g r a t u i t i e s w h i c h made p o s s i b l e my  at the u n i v e r s i t y .  attendance  1. GEOLOGICAL BACKGROUND As f a r as I h a v e h e e n publications dealing  g e o l o g i c a l background  British  Columbia  the l i t e r a t u r e  cult,  whether  McCabe and Cowan (1945) r e v i e w e d o f t h e a r e a i n q u e s t i o n and o f  of insularity.  I quote here —  on t h e g r o u n d o r f r o m  demonstrate  the recent  of  the B r i t i s h  Columbia  of  the hypothesis i n i t s b i o l o g i c a l This  the  region,  —  everywhere  on t o s a y , however, t h a t  fresh chance  a t any so u n i f o r m  the.vast majority o f  life."  These workers with  go  which  show e v i d e n c e o f g l a c i a l  and s y n c h r o n y and t h a t  and u n i v e r s a l  i s that  t h e c o a s t a l range s t r i p ,  change i s o v e r w h e l m i n g .  that  remains  estimates of  c o v e r a g e was  and a t o n c e ,  we a r e m a i n l y c o n c e r n e d , d o e s  climatic  the l o c a l  to prove, that  forms o f m o b i l e v e r t e b r a t e  uniformity  implications  criticism  as t o prove synchrony o f  g i v e n moment t h r o u g h o u t t h e r e g i o n ,  present  of research,  i s t h e a l l e g a t i o n t h a t , w h i l e t h e pheno-  glaciation,  as t o d i s p l a c e ,  the r e s u l t s  t h e most i n s i d i o u s  t i m e c a n n o t be so p e r f e c t  latest  review  i c e - c o v e r a g e o f almost any f r a c t i o n  menon i n i t s b r o a d s e n s e i s ' p r o v e d , elapsed  From t h i s  small  "Though i t i s n o t d i f f i -  to  unanswered.  Island  i n g e n e r a l , i n a paper d e a l i n g w i t h  mammals and t h e p r o b l e m of  geological  s p e c i f i c a l l y w i t h t h e Goose  group have been p u b l i s h e d . the  a b l e t o d e t e r m i n e , no  the evidence o f recent "The t i m b e r e d z o n e s  evidence o f recent  coverage.  The  s u c h d e g r e e s o f change w i t h i n t h e l i m i t e d  c o u l d have been i n t e r m i t t e n t o r l o c a l i z e d  show  area  i s almost n i l . "  ,  2 The  Goose I s l a n d  become o c c u p i e d influents elapsed That  by  group then i n a l l p r o b a b i l i t y  the  vegetation  i t harbours  s i n c e the  during  period  last  these animals invaded d i r e c t l y mainland  v i e w and  appears b i o l o g i c a l l y  affinities  seems l o g i c a l  to the mainland LOCATION AND  The  Goose I s l a n d  h a l f miles  a l a t i t u d e and  w e s t by  indirectly  sheet.  from  their  close  Columbia mainland coast,  51:58:00 d e g r e e s n o r t h , They a r e  l a t i t u d e ( F i g . 1) To  the  i n w i d t h known as from the  east  an  arm  Queen's Sound.  nearest  i n width  group at the  the  Broken Islands  and  the  are  i n turn completely Isolated. ( F i g . 14).  Gosling  the  This  substantial  and  the  of  Deep c h a n n e l s a p p r o x i m a t e l y one north  with  the  bounded on  lies  land mile  s o u t h ends f r o m  Rocks r e s p e c t i v e l y , which The  group c o n s i s t s o f  Goose I s l a n d u p o n w h i c h most o f  i n v e s t i g a t i o n s were c o n d u c t e d c o v e r s 4521.50 a c r e s .  The  areas of  773  acres;  others  are  as  Duck I s l a n d ,  263  acres;  Gull Island,  16.40  acres;  follows:- Gosling  and  and  128:27:00  mass, H u n t e r I s l a n d .  the  of  some t w e n t y - t h r e e  approximate c e n t r e .  s e p a r a t e s Goose I s l a n d  main i s l a n d s  the  forms.  of  this  separate the  has  from a geographic p o i n t  sound i n v i e w o f  British  the-open P a c i f i c .  eight miles  or  animal  of time which  o r Vashon I c e  group i s l o c a t e d  longitude  outermost i s l a n d at  the  GENERAL DESCRIPTION  o f f the  d e g r e e s west at t h e i r  sea  that  r e t r e a t of the  adjacent  one  i t c a r r i e s and  has  Island,  Swan I s l a n d , 168 Snipe Island,  6.39  acres; acres.  six the  FIGURE 1. Isolating Group.  - G e n e r a l L o c a t i o n and F a c t o r s o f t h e Goose I s l a n d  There i s i n a d d i t i o n considerable acreage o f rocky sea shore, sandy and boulder beaches which are.exposed i n v a r y i n g degrees with f a l l i n g t i d e s .  These expanses connect a l l  i s l a n d s o f the main group a t low t i d e w i t h the exception o f Duck I s l a n d , which remains separated by a narrow channel but which may d r y b r i e f l y during the periods o f extremely low tides. Over one hundred small reefs and i s l e t s are l o c a t e d i n close; p r o x i m i t y t o the shores of the main group.  The  m a j o r i t y o f these are l i t t l e more than sea washed r o c k s , but some o f the l a r g e r i s l e t s are vegetated.  The group i s  approximately s i x and one-half m i l e s long measured from north to south by two and one-half m i l e s wide, measured from east t o west.  The l a r g e s t i s l a n d o f the group i s indented  on the southwest side by a t i d a l mud and sand f l a t , r e f e r r e d to i n t h i s work as the lagoon.  The lagoon v a r i e s i n width  from a few yards t o h a l f a mile and extends approximately one m i l e i n a n o r t h e r l y d i r e c t i o n .  The f l a t i s bounded on  the west by low rocky sea shore and a narrow f r i n g e o f grass. On the northern and eastern sides l i e f l a t grassy meadows which vary considerably i n extent.  The Goose Islands are, f o r the  main p a r t , bounded on the outer p e r i p h e r i e s by rocky sea shore.  The few sandy sea beaches t h a t i n t e r r u p t t h i s con-  t i n u i t y sare i l l u s t r a t e d i n F i g . 2. Viewed from a d i s t a n c e the i s l a n d s appear h e a v i l y wooded, but c l o s e r i n v e s t i g a t i o n r e v e a l s that the main I s l a n d of Goose, and part o f Gosling I s l a n d are comprised of muskeg 1  FIGURE 2. - I l l u s t r a t i n g Extent of SandySea Beach (cross hatched) and T i d a l Mud F l a t ( s o l i d b l a c k ) . - The remainder of the shoreline i s rocky sea shore.  6 surrounded by a f r i n g e o f c o n i f e r o u s from 25 t o 300 yards.  f o r e s t varying  i n width  At some p o i n t s on the east coast the  muskeg extends through the f o r e s t t o the rocky sea shore. The  f o u r remaining i s l a n d s are timbered throughout.  extent  The  and f l o r a l c o n s t i t u t e n t s o f the v a r i o u s h a b i t a t s are  discussed  f u l l y i n the text.  Thus the Goose I s l a n d group supports w e l l d e f i n e d  floral  a s s o c i a t i o n s and h a b i t a t types c h a r a c t e r i s t i c o f the outer fringe of islands at this latitude.  I t i s , a t the same time,  a w e l l i s o l a t e d e c o l o g i c a l u n i t surrounded by deep expanses o f s a l t water which a r e subject t o strong tidal  currents.  Some o f the smaller  and t r e a c h e r o u s  i s l e t s mentioned a r e  w e l l i s o l a t e d i n themselves. CLIMATE " I t must be remembered that we have no data whatsoever for  t h e t r u e outermost s h o r e l i n e s , and t h a t the e x c e l l e n t  c l i m a t e o f t h a t narrow s t r i p i s o f f i c i a l l y unknown."  This  statement by McCabe and Cowan (1945) s t i l l h o l d s t r u e . records  No-  o f c l i m a t e a r e y e t a v a i l a b l e f o r the Goose I s l a n d .  group and other outer The  fringe islands.  >  c l i m a t e was indeed e x c e l l e n t on the group i n the  summer o f 1948.  The small mammal work was c a r r i e d out  during a p e r i o d o f unvarying sunshine, the days  repeating  themselves i d e n t i c a l l y i n the c l i m a t i c sense, thus e l i m i n a t ing  a p o t e n t i a l source o f e r r o r that i s a l l too p r e v a l e n t ,  o f t e n unavoidable,and n o t o f t e n mentioned i n works o f t h i s kind.  The mainland coast and i n n e r i s l a n d s during  that  summer s u f f e r e d  almost  c o n t i n u a l r a i n and  cold.  Prevailing  w i n d s c a r r i e d w i d e l y d i s p e r s e d cumulus c l o u d s f r o m over  t h e o u t e r f r i n g e and  their moisture During  on  the  the  sea,  t o t h e m o u n t a i n s , where t h e y  shed  c o a s t and  closely  t h e o c c a s i o n s when p r e c i p i t a t i o n  Goose I s l a n d s , t h e phenomenon o f r a i n  adjacent  islands.  d i d o c c u r on  approaching  Queen's Sound a g a i n s t t h e w i n d p r e s e n t e d  the  across  an u n u s u a l  sight.  W h e t h e r t h e c o n d i t i o n s t h a t p r e v a i l e d were a t y p i c a l i s difficult  t o say i n l i g h t  were a t y p i c a l , populations  o f inadequate  the e f f e c t ,  i f any,  c a n he d e t e r m i n e d  knowledge.  upon the  o n l y by  If  mammalian  future studies  after  s e v e r a l y e a r s o f o b s e r v a t i o n s have e s t a b l i s h e d annual precipitations, For climatic was from  r e l a t i v e h u m i d i t i e s , and  the p u r p o s e o f t h i s constancy  f o r t u n a t e and previous  constituted  summers s p e n t  an  mean  temperatures.  r e s e a r c h however, t h e  which e x i s t e d  they  a t the time  of  daily  operations  exceedingly pleasant  i n the northern c o a s t a l  change  areas.  8 FLORAL ANALYSES AND DESCRIPTION OF HABITAT TYPES An  i n i t i a l inspection revealed  the existence o f eleven  w e l l d e f i n e d v e r t e b r a t e h a b i t a t s on and about t h e i s l a n d s , some o f w h i c h may be r e g a r d e d  as d i s t i n c t  These h a b i t a t s a r e c o n i f e r o u s  f o r e s t , meadow, muskeg,  sea  shore,  coast  floral  s a n d y s e a b e a c h , t i d a l mud f l a t s ,  associations. rocky  beach d e b r i s ,  l i t t o r a l and p e l a g i c w a t e r s . Systematic  floral  analyses  meadow a n d muskeg h a b i t a t s . divided their  were c a r r i e d  The c o n i f e r o u s  out i n the forest, forest  i n t o two s e c t i o n s f o r b o t a n i c a l s t u d y  d i v e r s e appearance. vegetated  The r e m a i n i n g  was s u b -  because o f  h a b i t a t s , w h i c h were  were n o t t r e a t e d s y s t e m a t i c a l l y .  Rough a p p r o x i m a t i o n s o f h a b i t a t s i z e a n d o c c u r r e n c e recorded  i n view o f f u t u r e refinement  from a e r i a l  which had supposedly been taken d u r i n g Unfortunately sequently  illustrated  diagrammatic r e p r e s e n t a t i o n s and  t h e r e c e n t war.  i n Figures  indicating  2,  3,  relative  and con-  and 14 a r e dispersion  p o s i t i o n only. Coniferous Two t y p e s  climax  Forest  of plant associations are included i n the  general heading o f coniferous  in  photographs  such photographs a r e n o t i n e x i s t e n c e  t h e areas  were  a s s o c i a t i o n o f cedar,  forest.  One, t h e t y p i c a l  hemlock and spruce,  the other,  w h i c h c e d a r and h e m l o c k a r e i n a s s o c i a t i o n w i t h  yellow  c e d a r and yew ( F i g s . 3, 6, 7 ) .  This  jackpine,  stunted  a p p e a r s t o f o r m a n e c o t o n e between t h e s p r u c e  coast  forest  hemlock and  muskeg a s s o c i a t i o n a n d a l s o p r e d o m i n a t e s i n r o c k y  areas  on  F I G U R E 3. - D i s t r i b u t i o n o f S m a l l M a m m a l H a b i t a t Types on Goose I s l a n d - Cedar hemlock f o r e s t I s w h i t e , ecotone type f o r e s t i s s o l i d b l a c k , muskeg i s c r o s s . h a t c h e d a n d meadow i s s t i p l e d , b e a c h d e b r i s h a b i t a t i s i l l u s t r a t e d i n F i g , 8.  FIGURE 4. - C e d a r - H e m l o c k A s s o c i a t i o n on Goose I s l a n d . - Showing a s t a n d o f C a l a m o g r o s t i s a t t h e edge.  FIGURE 5. - Same A r e a f r o m a D i s t a n c e . Showing b e a c h D e b r i s a t t h e E d g e .  -  l i the  east coast o f  the  In view o f the that be  the  cause or  small area  they  are  normal p l a n t general  due  to p r e v a i l i n g  from  the.wooded a r e a s , north  and  to c l i m a t e .  succession  gradient  south  i n v o l v e d i t seems u n l i k e l y  causes l e a d i n g t o t h i s d i f f e r e n t i a t i o n  attributed directly  that  e c o l o g i c f a c t o r s coupled  the  sea  rock  the  cedar-hemlock stands  formations^  coastal slopes.  an a g e n t r e s p o n s i b l e f o r t h e  types  has  been.considered.  The  of  since f i r e  elapsed  almost i d e n t i c a l  other  outer  fringe groups,it  postulated  soil  succession  are  The  floral  general  important  spruce  McCabe and  Cowan (1945) i n t h e i r  t h e s e ' i s l a n d s seems t o  d i s t r i b u t i o n here  the o p p o s i t e . Pers.  I t has  r e d u c e d by  been p o i n t e d  Comm.) t h a t a l a c k o f  coniferous  length  i s l a n d s , and on  that  the  out  here.  hemlock,  and  substantiate  observations  the  the  of  existing  agents  cedar,  i s not  In fact  fire  associated plant .  development o f spruce sea.  flat  s c a r s were  swept t h e  causative  associated  the  con-  i n view of the  and  of  reasonably  of  seems more p r o b a b l e  d i s t r i b u t i o n of the on  the  seems  fire  distributions  f a c t o r s , drainage the  by  possibility  but  at  relatively  drainage  Some a n c i e n t forest,  with  on  diversification  o b s e r v e d i n b o t h type's o f time which has  A  i s a p p a r e n t t h r o u g h o u t most  for possible retaining effect  a d e q u a t e on. t h e  with  towards a spruce-hemlock climax.  although  tours of underlying  can  I t vrould seem r a t h e r ,  ends o f Goose I s l a n d a r e  ground.. E x c e p t  as  island.  that  outside  the  exposure  to  seems t o i n d i c a t e (Dr.  T. M.  seedling trees coupled  C.  Taylor,  with  the  FIGURE 6* - E c o t o n e of Goose I s l a n d .  I'ype F o r e s t  FIGURE 7. Muskeg.  l y p e F o r e s t a t Edge o f  - Ecotone  on l a s t  Coast  12.  13. h e a v y o c c u r r e n c e o f sphagnum t h r o u g h o u t  the  cedar-hemlock  a s s o c i a t i o n on Goose I s l a n d may  i n d i c a t e a post  condition.  accounting f o r the  of  Another  possibility  s e e d l i n g s i n t h e n a r r o w c o n i f e r o u s b e l t ' may  to the almost  complete  by P e r o r n v s c u s . h e m l o c k and lem  of plant  Whether t h e  utilization  s u c c e s s i o n cannot  not be  be  of available  T h i s however d o e s n o t  r e d c e d a r w h i c h may  account  remains  fascinating  by  short  of abrupt The  arbitrary.  The  here.  b e t w e e n t h e two  space,  giving,  to  another  outer islands present  source o f study to the p l a n t  floral  ecologist;  that  surprising.  types of f o r e s t  from  a  are character-  s p e c i e s over  t h e d i s t a n c e , an  a  appearance  c o m p o s i t i o n o f the c o n i f e r o u s f o r e s t  the Aldous  l e n g t h were c h o s e n  method  s p e c i e s r e c o r d e d on  the f o r e g o i n g r e f e r e n c e . coniferous type. w i t h i n each  plot  (1944).  a t random.  a t 50 y a r d i n t e r v a l s  by p l a n t  prob-  change.  a s s e s s e d by  spaced  The  discussed f u l l y  the gradual blending of i n d i c a t i v e  linear  cones  : s e r a i , stages represented are p r o g r e s s i n g  boundaries  ized  attributed  spruce  be u t i l i z e d .  t h e y h a v e n o t b e e n w o r k e d more t h o r o u g h l y i s The  lack  f o r the  towards a cedar-hemlock climax o r r e t r o g r e s s i n g type  climax  The  S t r i p s 300  P l o t s o f 1/100  on these  strips  was  yards  in  a c r e were  and  the  coverage  a mean b a s i s as d e s c r i b e d i n  Twenty-four  coverage  by  plots  were r u n i n  s p e c i e s and  are recorded i n percentage.  the  each  occurrence  (Tables I  and  II). The refined  methods o f a p p r a i s a l h e r e treatment  of f l o r a l  are not  c o m p o s i t i o n but  i n t e n d e d as as a g r o s s  a analysis  14* T a b l e I . — P e r c e n t a g e O c c u r r e n c e and Cover by P l a n t i n C e d a r - H e m l o c k F o r e s t o n Goose I s l a n d , B.C., J u l y  Plant 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32  Species  Sphagnum s p . P e l i g e r a canina Maianthemum b i f o l i u m Tsuga h e t e r o p h y l l a Menziesia ferruginea Vaccinium Gaultheria shallon Thuja p l i c a t a Rubus s p e c t a b i l i s Polypodium hesperium Struthiopteris spicant Picea sitchensis Prenanthes hastata Streptopus amplexifolius Tiarella trifoliata Usnea sp. Galium t r i f i d u m Coptis a s p l e n i f o l i a Lonicera involucrata Vaccinium caespitosum Fatsia horrida Calamagrostis inexpansa Aspidium spinulosum L y s i c h i t o n americanum Stereocaulon sp. Malus r i v u l a r i s Rubus p e d a t u s Alnus s i t c h e n s i s Pteris aquilina Conioselium gmelini V i c i a gigantea Moneses u n i f l o r a  Occurrence 100 83.3 75.0 70.8 66.6 62.5 58.3 50.0 50.0 45.8 45.8 37.5 29.1 28.1 25.0 16.6 12.5 12.5 12.5 12.5 12.5 12.5 8.3 4.1 4.1 4.1 4.1 4.1 4.1 4.1 4.1 4.1  Species 1948. Cover 56.8 9.8 18.2 33.7 7.5 6.8 22.7 17.7 7.2 2.2 4.3 16.4 0.2 0.2 1.2 8.3 0.6 2.7 0.4 0.6 1.6 4.3 0.4 0.2 0.2 2.9 1.2 0.2 0.2 0.2 0.2 0.2  T a b l e I I . — P e r c e n t a g e O c c u r r e n c e and C o v e r by P l a n t S p e c i e s i n E c o t o n e Type F o r e s t o n Goose I s l a n d , B.C., J u l y 1948.  Plant  Species  Gaultherla shallon Sphagnum s p . Thuja p l i c a t a Tsuga heterophylla Maianthemum b i f o l l u m Struthiopteris spicant Coptis a s p l e n i f o l i a Menziesia ferruginea Vaccinium o v a l i f o l i u m Carex s i t c h e n s l s Charaecyparis nootkatenais Calamagrostls inexpansa Pinus contorta Ledum g r o e n l a n d i c u m Llnnaea borealis Caltha b i f l o r a L y s i c h i t o n americanum Picea sitchensls Taxus b r e v l f o l i a Empetrum n i g r u m Rubus s p e c t a b i l i s Pteris aquilina Coptis asplenofolia Polypodium hesperium Streptopus amplexifolius Stereocaulon sp. Cladonia sp. Usnea sp. Lycopodium selago Malus r l v u l a r i s Sanguisorba sitchensls Drosera r o t u n d i f o l l a P e l t i g e r a canina  Occurrence 100 100  91.7 83.3 79.1 75.0 75.0 66.7 62.5 58.3 45.8 41.7  37.5 37.5 33.3 33.3 33.3 20.8 16.7  16.7 16.7  16.7 16.7 12.5 12.5  " 8.3 ' 8.3 8.3 8.3 4.1 4.1 4.1 2.0  Cover  38.1 55.2 40.2  16.9 3.9 7.9 4.;3  5.S 3.1  6.0 15.2 2.1  14.8  3.9 1.7 4.4 1.7 11.9 3.9 1.9 0.8 1.9 1.9 0.6 1.7 0.4 1.4 0.4 0.4 0.2 0.2 0.2 1.0  16. i n d i c a t i n g the r e l a t i o n of the plant species involved regarded from a cover point of view rather than by numbers of i n d i v i d u a l plants occurring. The Muskeg Habitat Comparatively small areas of muskeg are located on Gosling Island but the study of t h i s habitat was confined to Goose Island proper.  Here the main part of the i n t e r i o r  i s comprised of t h i s type (Figs. 3 , 8, 9).  The i s l a n d '  resembles a shallow saucer or catch basin with r i s i n g , timbered coastal slopes l e v e l l i n g o f f and depressing generally towards the centre forming a shallow rim around the Island.  The topography of the i n t e r i o r i s marked by  numerous rocky outcroppings, ridges and low h i l l s of varying size forming a series of secondary- catch basins. The low lying ground i s characterized by pot holes and a general coverage of sphagnum moss and lichens.  From t h i s  c  understor^y other plants have established  themselves.  Stunted jack pine, many of them dead,are dispersed over the area.  The higher ground, h i l l s and ridges are wooded with  the ecotone type f o r e s t . The presence of t h i s muskeg i s probably due to hydrophytic conditions resulting from the damming e f f e c t of the catch basins, i n other words, inadequate drainage.  This i s  borne out by the fact that i n periods of heavy p r e c i p i t a t i o n the pot holes become f i l l e d with water, the muskeg because generally very wet and the several small streams draining the i n t e r i o r come i n spate carrying the great excesses over  FIGURE 8 . - Muskeg a t S o u t h E n d o f Goose I s l a n d . . May, 1948.  FIGURE 9» Muskeg I n C e n t r a l Goose I s l a n d . May, 1948. - K o t e t h e dead P i n u s c o n t o r t a debris i n pothole. -  18.. the  c o a s t a l rim to the  almost The  sea.  The  streams i n a short w h i l e  are  d r y a g a i n , mere t r i c k l e s w h i c h a r e a l m o s t s t a t i o n a r y .  p o t h o l e s however r e t a i n t h e w a t e r f o r a much g r e a t e r  l e n g t h o f t i m e , d e p e n d i n g u p o n t h e i n t e n s i t y and h u m i d i t y  of  the p r e v a i l i n g w e s t e r l i e s . A line  i n t e r c e p t method was  composition collected  o f t h e muskeg.  from a c o v e r  r i g h t wires inches  were u s e d  long.  occurring  of overlap. of  p o i n t of view only.  E a c h 100  was  percent.  total  recorded  o f 300  Twenty-four p l o t s  levels f o r the  spaced  a t random r u n n i n g  from f o r e s t Table percentage  edge t o f o r e s t III lists of cover  of the  the l i n e  along  If still  occurred-, t h e t h r e e c o v e r show a p e r c e n t a g e  stout  as a p l o t ,  cover  100  the and  could,  up100 one  species  regardless  percent  w i t h 100  higher  floral  were  cover  percent  s p e c i e s that chanced to i n t e r c e p t  l e n g t h o f the l i n e .  selected  Total  example, i n a g i v e n p l o t  growing  Two  regarded  measured i n i n c h e s a l o n g For  data  a taut horizontal l i n e  i n c h e s was  sphagnum moss c o u l d be  some h i g h e r  i n a s s e s s i n g the  H e r e a g a i n t h e raw  to spread  i n c h r e p r e s e n t i n g one  used  growing  the  species  theoretically,  plot.  a t 100  yard intervals  transversely across  were  t h e muskeg  edge.  s p e c i e s o c c u r r i n g i n terms occurrence  i n plots.  of  of  19 T a b l e I I I . — P e r c e n t a g e O c c u r r e n c e a n d C o v e r by P l a n t i n Muskeg o n Goose I s l a n d , B.C., J u l y 1948. 'Plant  Species  C l a d o n i a sp. Sphagnum s p . Myrica gale J u n i p e r u s communis Ledum groenlandicum Sanquisorba s i t e h e n s i s Empetrum n i g r u m Carex limnosa Scirpus caepitosus Chamaecyparis n o o t k a t e n s i s Pinus contorta Lycopodium selago T o f i e l d l a intermedia Drosera r o t u n d i f o l l a Eriophorum chamissoris Carex s t y l o s a Caltha b i f l o r a Kalmia p o l i f o l i a • Rynchospora a l b a Gaultheria shallon Coptis asplenlfolia Linnaea b o r e a l i s Rubus p e d a t u s Thuya p l i c a t a Alnus s i t e h e n s i s Struthiopteris spicant Habenaria leucosthchys Coptis a s p l e n i f o l i a Gentiana propinqua Pinquicula vulgaris Carex s i t e h e n s i s Plantago macrocarpa Calamagrostis inexpansa Deschampsia c a e p i t o s a Stereocaulon sp. B a r e Rock  Occurrence 95.8 91.6 91.6 72.5 58.3 58.3 50.0 50.0 41.7 37.5 33.3 29.2 25.0 25.0 25.0 20.8' 16.7 12.5 12.5 -8.3 8.3 8.3 8.3 4.2 4.2 4.2 • 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.2 4.2  '  Species  Cover 63.8 67.0 12.7 17.2 3.1 4.9 5.5 1.7 4.4 5.3 4.7 2.4 0.7 0.5 0.5 0.6 .1.5  6.2  0.8 0.2 0.6 0.1 • 0.2 0.04 1.1 0.5 0.04 0.04 0.1 0.1 0.04 0.04 0.04 0.04 0.2" 0.8  20.  The Meadow. H a b i t a t The meadow h a b i t a t few  o n t h e Goose I s l a n d s i s l i m i t e d  acres bordering the shores  The meadows o n t h e m a i n i s l a n d , done, a r e c o n t i n u o u s  into rills  the coniferous forest draining  in  the area.  a permanent plants.  dry s p e l l s  l o n g exposure  or wholly f i l l e d  on  life  vegetated  life,  of transitional  t h e shore; c o n t a i n  lose  hydrophytic  t h e i r water i n  by a c c u m u l a t i n g  by s a l t water  Salicornia  (sp.) i s dominant  t h e s e a w h i c h a r e washed  ( F i g . 12). Others  c o m p l e t e l y by P l a n t a g o m a r i t l m a  once been a p o t h o l e .  d e b r i s from t h e  T h e s e a r e a s become v e g e t a t e d b y  o f t h e meadow.  patterns o f irregular  feet  ( F i g . 1 1 ) , w h i l e o t h e r s become  those immediately-bordering  - periodically  where  o f t h e meadowsj some o f t h e s e become  annually dying vegetation. the p l a n t  series  e x p o s i n g mud b o t t o m s , o f t e n two a n d t h r e e  after  partially  chiefly  pot holes are located  w a t e r and h a r b o u r  devoid o f plant  below t h e g e n e r a l l e v e l caked  a few f e e t  occur.  Those nearer  supply o f f r e s h  Others,  from  assessment  N a r r o w n e c k s o f meadow p e n e t r a t e  and b r a c k i s h - w a t e r  formation.  3, 9a, 1 0 ) .  where t h e f l o r a l  They r e p r e s e n t a s t r i k i n g  stages i n s o i l  (Figs.  at several points,  the i n t e r i o r  Numerous f r e s h  isle.  but vary i n width  t o between 50 a n d iOO y a r d s .  to a  o f the l a g o o n and t o t h r e e  small areas on t h e south western  was  .  darker green patches  h a v e become  leaving  only  t o mark what h a d  On some o f t h e s e , t h e " h a r d e r "  g r a s s e s o f t h e meadow a r e e n c r o a c h i n g .  FIGURE 9 a . May,  Goose  I s l a n d Meadows  In  1948.  Figure  10.  -  Same a r e a  in July,  1948.  21.  FIGURE 11. - Dry P o t h o l e Meadows. J u l y , 1948.  on t h e Goose  island  FIGURE' 12. - Edge o f Meadow a t S a l t W a t e r on Goose I s l a n d . July,, 1948. - .Note S a l a c o r n i a s p . E n c r o a c h i n g on S a n d .  22.  23. The  gradual  represented  transitional  h e r e may  well  was in  field,  u n i t was  only  being  the  o f w i r e and  considered  random o v e r  of  sample method o f  used i n t h i s h a b i t a t . the  the  1000  points  points  The  sphagnum o r  sample u n i t c a r r i e d 18  1942)  improvised points.  Each  s u c h p l o t s were s e l e c t e d o f 1000  plot.  points,  10  Seventy-one  percent  percent  the  remaining root  29  of a plant.  cladonia occurred,  mass were i n c l u d e d .  where c e r t a i n s p e c i e s  t h r o u g h t h e moss a c c o u n t i n g  at  points  the  recorded  i n which  In  cases  a l l points  S i m u l t a n e o u s s t r i k e s were  of grass  were g r o w i n g  for a total  percentage  up  greater  100. The  point,  r e s u l t s here are not  but  as  meadow f r o m occurring,  an  relative as  On  illustrated  the  drifts  f o u n d p i l e d up  on  i n Table  Beach Debris of  and  the  jams become l o d g e d .  floral  the  cover  the  composition of  the  species  IV.  British of  Columbia c o a s t , debris  stumps o f d e a d  sea  stand  Habitat  permit, a welter  logs, roots,  from  numbers o f d i f f e r e n t p l a n t  many s t r e t c h e s  tidal  viewed  i n d i c a t i o n o f the  The  of  (Clarke,  p e r c e n t a g e com-  the  the  a  b a r e g r o u n d . The  striking  than  56  last  a c t u a l l y struck  where b e d s o f  point  cardboard,  i n the  p o s i t i o n i s c a l c u l a t e d on the  range assessment  a p l o t and  struck  t o meadow  ecologist.  meadow f o r a t o t a l  included  hole  b e a r f u r t h e r i n v e s t i g a t i o n by  competent a g r o n o m i s t o r p l a n t A point  stages from pot  beaches.  The  Additional debris  composed  coniferous  where mainly  trees  u n i t s m a k i n g up accumulating  is these  through  T a b l e I T . — P e r c e n t a g e C o m p o s i t i o n o f Meadow by P l a n t o n Goose I s l a n d , B.C., J u l y , 1948. Plant Species Sphagnum s p . C l a d o n i a sp. T r i g o l o c h i n maritima Deschampsia c a e s p i t o s a S a l i c o r n i a ambigua Juncus b a l t i c u s Carex bauxbaumii Empetrum n i g r u m Plantago maritima Fetuca rubra Eriophorum chamissonis P o t e n t i l l a anserina Plantago macrocarpa Hordeum nodosum Achillea millefolium Ledum g r o e n l a n d i c u m Glaux m a r i t i m a Carex l i m n o s a Elymus a r e n a r i a C a s t i l l e j a miniata Calamagrostis inexpansa Gaultheria shallon Agrostis exarata Sisyrinchium idahoense Cochlearia o f f i c i n a l i s Mianthemum b i f o l i u m Atriplex patula  Composition 30.0 15.5 13.1 7.9 6.6 6.2 5.5 5.2 4.1 4.1 3.4 2.8 2.4 2.1 2.1 1.7 1.7 1.0 1.0 0.6 0.6 0.6 0.3 0.3 -.0.3 0.3 0.3  Species  FIGURE 13. I s l a n d , B.  - Beach D e b r i s H a b i t a t C. July, 1948.  on  Goose  25.  the  years often  the  f o r e s t edge, and  short  distances.  height of  borne.  and  of the  agents  s u c h as  mass u n t i l of  rock  piled  state of  the  and  mud  shoreline.  high  s a n d s , and  These c o a s t a l l o g by  for  to  a  ferocity  encroaching  b e a c h combine w i t h  i n anchoring  type u t i l i z e d  to  t i d e u p o n w h i c h t h e y were  the  other  accumulating  i t o f t e n becomes a p e r m a n e n t l y f i x e d and  the  integral  jams f o r m a  c e r t a i n species  dis-  of birds  and  mammals. The  beach debris h a b i t a t  o c c u r s on  a l l sides of the  favourable  one  the  are  twenty f e e t , depending upon the  f o r e s t edge and  tinct habitat  25  to  water l i n e  f o r e s t proper  logs~  Interlocking units, shifting  plants  small  sometimes i n t o t h e  I n many e a s e s t h e  of fifteen  the g a l e  part  e x t e n d s t h e mass f r o m t h e h i g h  yards,  ( F i g s . 13, and  to t h r e e  the  Goose I s l a n d  are  i n most c a s e s i s composed o f i n depth to four  f o r e s t edge o f  this habitat,  where t h e  s u b s t r a t u m i s composed o f  older debris  c a r r i e s t h i c k mats o f  the  wood has  furnished  from  Gaultheria,  Rubus, h a v e e n c r o a c h e d t o a c o n s i d e r a b l e sand.  of  feet.  A l n u s and  decaying  group  I t seldom e x c e e d s a w i d t h  layers varying  Along the  the  i s l a n d s where c o n d i t i o n s  14,).  debris  on  extent,  Here a l s o ,  the  sphagnum moss b e l o w w h i c h  bases f o r small  cedars  and in  h e m l o c k s and  lesser plant  central line  of  irregularly grow up over the  the h a b i t a t ,  occurring  among t h e logs,  life.  Lower down t h e  but  still  beaches,A t h e  above h i g h  t i d e mark,  s t a n d s o f Lathyrus» A t r i p l e x and  debris.  ?he  former o f t e n  intertwining with  the  spreading  woody p l a n t s  Vicia back  already  FIGURE 14. - D i s t r i b u t i o n o f B e a c h D e b r i s and B o u l d e r B e a c h on Goose I s l a n d , B. C. 1948. - B e a c h D e b r i s i n s o l i d b l a c k , b o u l d e r beach stippled.  28. established  t o form dense t h i c k e t s over the l o g s  h i g h beach. logs,  Beneath  along  the  t h e s e t h i c k e t s , between and u n d e r  the  a r e mazes o f p a s s a g e s ,  s u i t e d as a d w e l l i n g The  place  outer margin  r e g u l a r l y by  runways and  o f the beach  debris  the spaces smaller for  plants.  of  t h e s e may  on r o c k y s e a s h o r e  much l e s s a b u n d a n t .  and  c a s t up  be  temproary  jams b e a r no  and w i l l  plant  life.  all  differing  coast  and  so o n .  debris  on-  habitat  I t i s obvious  tidal  then, t h a t  i n c e r t a i n a s p e c t s , a r e t o be  on t h e Goose I s l a n d The  As p r e v i o u s l y  Rocky Sea  indicated  p a r t o f the o u t e r s h o r e l i n e  group  as  the  drift,  many t y p e s ,  found along  shores o f the c o a s t a l i s l a n d s i n B r i t i s h  this holds true  Some  storms.  development o f permanent beach  and  bases  d i s a p p e a r under the  p r e v a l e n c e and i n t e n s i t y o f s t o r m s ,  exposure  with  suitable  depends u p o n a m u l t i t u d e o f f a c t o r s , t i m e , n a t u r e o f bases,  plant  I n some a r e a s h o w e v e r ,  s e a weed, f o r m i n g  Newly e s t a b l i s h e d  of winter  The  life.  b e t w e e n t h e l a r g e r u n i t s h a v e become f i l l e d  debris,  slaught  w h i c h i s washed  the t i d e s , i s devoid o f p l a n t  i s generally  admirably  f o r mice.  Where t h e l o g s h a v e "hung u p " life  chambers  the  Columbia;  well.  Shore  r o c k y sea shore forms a o f t h e Goose I s l a n d  group  large (Figs.  2,15,16). The m a r g i n generally thirty  o f r o c k between the  n a r r o w and p r e c i p i t o u s ,  f e e t i n width.  sea and  seldom  the f o r e s t i s  exceeding  twenty  or  FIGURES' 15 a n d 16. - T y p i c a l R o c k y o n G o o s e I s l a n d , B . C. 1948.  Sea  Shore  2  9  .  50. The  vegetation i s sparse, P o t e n t i l l a v i l l o s a  with F r a g a r i a c h i l o e n s i s  also present.  dominating,  H e r e and t h e r e a n  o c c a s i o n a l t w i s t e d s p r u c e h e l p s b r e a k t h e monotony o f l i c h e n encrusted rock. shelter plants S  P»>  Nearer  the forest  and a n a c c u m u l a t i o n  edge, where t h e r e i s  of s o i l  i n the crevices,  as T e l l i m a g r a n d ! f l o r a . M o n t i a  Erigeron salsuginosus, Barbarea  sarmentosa, vulgaris,  such  Trientalis  and C a s t i l l e j a  sp. a r e found. The shore  percentage  composition  of flora  on t h e r o c k y sea  o f t h e Goose I s l a n d s i s n o t p r e s e n t e d The  ducted  f l o r a l a n a l y s e s o f t h e f o r e g o i n g h a b i t a t s was  con-  i n J u l y a t t h e a p p r o x i m a t e mean o f t h e f o u r months  spent upon the i s l a n d s . appearing  varieties  appear i n t h e p l o t  I n c o n s e q u e n c e some e a r l i e r  o f p l a n t s were gone o r h a d n o t  when t h e work was b e i n g  conducted.  results.  did not permit  the continued  In addition,  running  p o s s i b l e v a r i e t y was r e p r e s e n t e d ,  and l a t e r appeared  These o f course,  abundant p l a n t s d i d n o t chance t o f a l l  fairly  here.  do n o t  some o f t h e l e s s  within a plot.  of plots u n t i l  Time  every  as had been p l a n n e d ,  but a  r e p r e s e n t a t i v e c o l l e c t i o n was made i n May and J u n e .  . I do n o t m a i n t a i n p l e t e * but  I do f e e l  accomplished  t h a t t h e work h e r e  presented has  i t s i n t e n d e d o b j e c t i v e , , i n t h a t i t g i v e s an  i n d i c a t i o n o f the type, the r e l a t i v e  t h a t t h e c o l l e c t i o n o f p l a n t s i s com-  diversification  a n d , i n most  abundance o f t h e c h a r a c t e r i s t i c  flora  cases,  on t h e  various habitats discussed. The  plant collection  from  t h e Goose I s l a n d s i s h o u s e d  FIGURES 17 and 1 8 . - B o u l d e r B e a c h between Goose and G o s l i n g I s l a n d , B. G. 1948.  31.  32. at  t h e P r o v i n c i a l Museum i n V i c t o r i a , The m a r i n e f l o r a  coast l i t t o r a l t h i s paper,  o f t h e sandy s e a beach, b o u l d e r  and p e l a g i c w a t e r s ,  i s not presented Boulder  The  boulder  B.C. beach,  b e i n g beyond t h e scope o f  here. Beach  beach o c c u r r i n g upon t h e group I s l o c a t e d  for  t h e m a i n p a r t between t h e s o u t h  end  of Gosling Island.  end o f Goose a n d t h e n o r t h  A considerable stretch  i s l o c a t e d on  t h e west c o a s t o f Goose I s l a n d ,  while short stretches l i e  b e t w e e n G o s l i n g , S n i p e and G u l l  Islands  (Figs.14,17,18).  S a n d y S e a B e a c h a n d T i d a l Mud Figs.  2, 19 and 20 i l l u s t r a t e  h a b i t a t s on t h e group. beaches except  Flat  the extent o f these  A l l e x p a n s e s shown a r e t r u e s a n d y  p o r t i o n s o f the lagoon.  c o n s i d e r a b l e amount o f s o f t mud  (Figs.  Here there i s a 2, 2 1 , 22) o c c u r r i n g  a l o n g t h e c e n t r a l d e p r e s s i o n s and g e n e r a l l y m i x e d w i t h t h e sand In  on t h e f l a t s  a t the head.  a s t a g e b e t w e e n t i d a l mud  sand  The a r e a h e r e  flat  appears  t o be  and sandy s e a b e a c h w i t h  predominating. MAMMALIAN POPULATIONS D i s c u s s i o n o f Methods, P r o c e d u r e s . a n d It  i s g e n e r a l l y conceded  Application  t h a t up t o , and i n c l u d i n g t h e  p r e s e n t t i m e no s a t i s f a c t o r y methods o f a c c u r a t e l y m e a s u r i n g per u n i t  d e n s i t i e s o f s m a l l mammals h a s b e e n d e v i s e d .  Various workers,  Dice, B l a i r ,  o t h e r s have devoted ing  much t i m e  nature o f the r e s u l t s  Bole, Stickle,  a n d many  to the subject.  The c o n f l i c t -  o b t a i n e d by t h e s e w o r k e r s i n t h e  FIGURES 19 and 20. - S a n d y S e a B e a c h on Goose I s l a n d , B. C. 1948.  use  o f the  snap t r a p and  the  live  s e r i o u s doubts upon the v a l i d i t y contributions i n pointing the  out  censuring  Stickle  published the  of  p i t f a l l s and  difficulties  conclusion  She  population  f i g u r e s three  live  indicated  indicates that  also  that  The  the use  of  live  in  When t h e  quadratand a smaller trapped,  i t was  densities this  that  c a l c u l a t e d range,  the  as  indicate  fewer animals per  questionable  live  i n one  t r a p methods a r e  mark  snap  as  those obtained respect,  appreciably  t h e m i c e on  that  the  quadrat  quadrat  c a l c u l a t e d range  the  fact  that  t r a p methods a r e obtained  per  unit  another. yield  to  than a c t u a l l y occur.  snap t r a p p r o c e d u r e s  The  upon  be  approximations with a tendency u n i t area  had  based  based  must  are used i t i s probable that  methods combined, may  large  snap  errors  of  are  more  d i r e c t i o n than t h o s e r e s u l t i n g from In  by  p r e v i o u s l y marked m i c e  r e s u l t s so  e x a g g e r a t i o n r e s u l t i n g from extensive  the  than the  the  regarded  When l a r g e . q u a d r a t s  of  I n view o f  a r r i v e d a t by  two  t r a p s were removed f r o m a  greater  trap data.  the  method r e s u l t s i n  traps  of  c e n t r a l area  revealed  come f r o m d i s t a n c e s live  live  great  in  1958).  trapping,  experiment, i n t h i s  range o f o p e r a t i o n s  question.  latter  t i m e s as  trap procedure.  objectives  f i g u r e s than does  the  shortened the  the  (Dice,  that l i v e  r e l e a s e , y i e l d s more a c c u r a t e  the  Many  encountered  ( 1 9 4 7 ) , i n an e x p e r i m e n t a l c o m p a r i s o n o f the  cast  e i t h e r method.  have accomplished v a l u a b l e  trapping.  on  of  s m a l l mammal p o p u l a t i o n s  methods a r r i v e d a t and  t r a p quadrat have  utilization  a c a l c u l a t e d mean  of  no  live  both  representing  21 a n d 22 - S a n d y S e a B e a c h i n L a g o o n o n G o o s e I s l a n d , B. C. - N o t e w e t a r e a s i n b a c k g r o u n d d e m a r k i n g a r e a s o f t i d a l mud flat.  FIGURES  35  more t r u t h f u l f i g u r e s than does t h e s o l e use o f e i t h e r one. When smaller quadrats are used, i n which t h e l i n e a r ranges o f the mice i n q u e s t i o n a r e undoubtedly g r e a t e r than the dimensions o f those quadrats, i t i s obvious t h a t p e r u n i t area d e n s i t y e s t i m a t e s based  s o l e l y on the area  covered by t r a p s w i l l r e s u l t i n exaggerated figures..  Some  c o r r e c t i o n then, must be made t o compensate f o r t h a t p a r t o f t h e rangesof the mice which chance t o l i e o u t s i d e o f the p l o t upon which they were taken.  Such was the case i n the  work conducted on the Goose I s l a n d s .  I n consequence, the  u n i t a r e a d e n s i t y f i g u r e s presented here are open t o q u e s t i o n and a r e p r e s e n t e d o n l y as p o i n t s o f i n t e r e s t and comparison  to. the percentage c a l c u l a t i o n s upon which the  r e l a t i v e abundance o f s m a l l mammals i s based i n t h i s  paper.  P o t e n t i a l l y t h e l i v e t r a p method,v,has g r e a t e r p o s s i b i l i t i e s than has snap t r a p p i n g .  The l a t t e r method k i l l s the  mice as they are taken and consequently t h e c a l c u l a t i o n o f i n d i v i d u a l ranges i s i m p o s s i b l e .  The removal o f a number  o f animals from a g i v e n area a l s o g i v e s r i s e t o sources o f error. The major o b j e c t i o n to the use o f l i v e t r a p s i n t h i s type o f r e s e a r c h i s the i n f l u e n c e which these t r a p s exert upon the range o f i n d i v i d u a l mice.  S e v e r a l methods o f  e l i m i n a t i n g t h i s e f f e c t have been suggested.  Basically a l l  o f the methods operate on the same p r i n c i p l e , t h a t o f c l o s i n g a t r a p o r group o f t r a p s on a quadrat o r a d j a c e n t q u a t r a t s thus a l l o w i n g the mice to wander f u r t h e r a f i e l d and i n t o  57. t r a p s they o t h e r w i s e would n o t have v i s i t e d . methods i n v o l v e a l a r g e number o f t r a p s and hours.  I n a d d i t i o n the ranges  directly proportional  to the  a set p a t t e r n i s used.  arrived  Most o f subsequent  at w i l l  still  and  I t Is g e n e r a l l y acknowledged t h a t  movements and  other variable  A live  by Cowan (1949,  c o m p l e t i o n o f an  relatively  and  further  points  from  a r e no  suggested  fewer  t r a p s has  Beginning  the c e n t r a l area.  quadrat and been p o s t u l a t e d  at a c e n t r a l area  a number o f l i v e  of traps i s then  Howard  s e t around  the s p e c i e s i n q u e s t i o n .  stated  or  On  the range  generally, a  released.  A  peripheral  central area at a  dis-  o f the i n d i v i d u a l s  succeeding n i g h t s t h i s  to the c e n t r a l  the  sufficient  line  of of  a r e a u n t i l marked m i c e  retaken.  I n d e n s e c o v e r t y p e s where a s h o r t c r u i s i n g expected  and  (1949) h a s  the central area after  tance g r e a t e r than the expected  t r a p s i s moved c l o s e r  traps  further  Eventually a point  a s i m i l a r method, i n w h i c h , from  of  a t w h i c h t h e o r i g i n a l l y marked  longer being taken.  are l i f t e d  are being  mammalian  The m i c e t a k e n a r e marked  number o f a n i m a l s h a v e b e e n marked and line  seasonal  succeeding n i g h t s the t r a p s are set  s h o u l d be r e a c h e d  animals  traps  on  are  investigation  an e x p a n d i n g  i n a given habitat,  are set i n c l o s e p r o x i m i t y . and  as  time.  P e r s . Comm.).  suitable dimension  released  factors affecting  t r a p method e m p l o y i n g  possibly involving  remain  o t h e r s , they  impractical.  w i t h i n a s h o r t space o f  man  s p a c i n g o f t h e t r a p s as l o n g  For these reasons  populations n e c e s s i t a t e the  these  t h e s e methods may  w e l l prove  r a n g e may  effective.and yield  be data  from which per reasonable  unit  accuracy.  necessitate  the use  been s u b j e c t e d accuracy In  the  present  the l i m i t a t i o n s of  represented the  I n open cover of  f a r too  he  calculated  with  t y p e s , however, they  many t r a p s .  trials  study  to the  their  Until  they  practicability  snap t r a p s o n l y  best  imposed by  the  three  can  may have  and  unknown.  These I u t i l i z e d  adequacies  densities  to f i e l d  remain  The  area  the  fully  factors  s t u d i e d by use  (apart from  Peromyscus m a n i c u l a t u s ,  available. realizing  and  by  the i n -  snap t r a p  quadrat  equipment.  only t e r r e s t r i a l  Goose I s l a n d s  ability  variable  available  species  o f my  were  of  mammals f o u n d  bats).  Mlcrotus  occupying  These animals  longicaudus  and  are  Sorex  obscurus. Investigations island 7  ( F i g . 23)  when t h e Four  for  first  quadratwere confined  commenced o n May  young M i c r o t u s  quadrats,  three  habitats  and  by  70  yards  consecutive days occupied  by  these  traps b a i t e d with walnut  in  lines  three  constituted  the  running  transversely.  deemed m o s t l i k e l y  conforming  to  the  five  f i v e yards  of  the  outer margin of  placed. sidered  The  yard  margin formed  i n per  yard  acre  by  this  calculations,  contained intervals  the  No  t r a p was  quadrat  five  yard  lines  A l l traps  to catch mice while  interval.  run  four  T h i r t e e n such  complement f o r each q u a d r a t .  set i n niches  the  quadrat  set at f i v e  June  wide, were  n i g h t s i n each of  and  main  running.  yards  mammals.m E a c h  39  of  20  the  t e r m i n a t i n g on  were observed  l o n g by  and  22,  to  were  s t i l l  set w i t h i n  i n which i t strip  figuratively  when  disperses  was  conthe  FIGURE 23. ~ Location of Mammal Quadrats on Goose Island* - Numbers 1,2,3,4, coniferous forest; numbers 5 , 6 , 7 , 8 , muskeg; numbers 9. 1 0 , 1 1 , 1 2 , beach debris; numbers 13,14,15,16, meadow©  40. animals  taken,  three times is  over  the  arbitrary  three times  an a r e a l e s s ,  area a c t u a l l y  and  b a s e d on a n  the per  r e s u l t e d had  live  effect  quadrat  i n F i g . 24.  yards>  than  This  area  traps.  exaggeration  The  400  i .-r  roughly  traps.  taken  f o u r standard  ample, P e r o m y s c u s t a k e n The  The  7 0 x 2 0 x 4 s 5600 s q u a r e  yards.  shorten-  standard illustrated  acre d e n s i t i e s ,  the  total  i n a given h a b i t a t i n three nights p l o t s was  considered.  i n a l l beach d e b r i s p l o t s total  yard  range  Goose I s l a n d i s d i a g r a m m a t i c a l l y  sexes.  of  square  as c o m p e n s a t o r y f o r t h e  I n c a l c u l a t i o n of per  o f t r a p p i n g on  o f both  expected  t r a p s been u s e d .  number o f i n d i v i d u a l s  65  e n c l o s e d by  of the h y p o t h e t i c a l l i v e  used on  square  a c r e d e n s i t y f i g u r e t h a t would have  d i f f e r e n c e i s regarded ing  by 400  area  e n c l o s e d by  For  ex-  totalled  four  T h e r e a r e 4840 s q u a r e  plots= yards  in  o  one  acre.  The  c a l c u l a t e d d e n s i t y s 4840 x 6 5 = 6600  a c r e o f beach d e b r i s h a b i t a t then, utilized  by an  were u t i l i z e d  estimated  and  only.  are presented  The  a constant, unbiased  presented by  1.  i n percentage  analysis of variance  level  of p r o b a b i l i t y  The  be  Similar calculations  at t h i s p o i n t , t h a t the d e n s i t y  observed  comparison  i n the d i f f e r e n t h a b i t a t s  trapping procedure. and  the  raw  (Snedecor,  i t has  The  results  are  data have been t r e a t e d 1958).  been i n d i c a t e d  d i f f e r e n c e s i n the  o f a l l s p e c i e s c a n n o t be  as a b a s i s f o r  d i s c u s s i o n s a r e b a s e d u p o n t h e number  of i n d i v i d u a l s of a species taken by  to  One  f o r each s p e c i e s i n each h a b i t a t .  so c a l c u l a t e d  interest  i s considered  56 P e r o m y s c u s .  I wish to s t r e s s again, figures  56.1.  Taken at the  .01  that:—  t o t a l number o f  a s c r i b e d to chance.  individuals  In other  words  F I G U R E 24. - Standard Trapping u s e d on Goose I s l a n d .  Quadrat  A  • 20 YDS. 10 YDS.—  ->  ©  o o  S3 >  2  o  O  o  6  o  o  O  6  ©  ©  42. the p r o d u c t i v i t y o f the v a r i o u s h a b i t a t s i n r e l a t i o n species d i f f e r s  due t o some p r o d u c t o f t h e h a b i t a t s . 2 . T h e  d i f f e r e n c e s observed  i n t h e number o f i n d i v i d u a l s  species taken i n d i f f e r e n t chance, in  but suggests  different  one h a b i t a t  that  quadrats  cannot  of different  be a s c r i b e d t o  some s p e c i e s "do b e t t e r "  q u a d r a t s . 3. T h a t  t h a n i t does i n a n o t h e r .  specific habitat  intrinsic  Consequently, the  or  t y p e s i s n o t due t o c h a n c e ,  characteristics  than o t h e r s  one s p e c i e s d o e s b e t t e r i n  observed d i s t r i b u t i o n o f i n d i v i d u a l s o f d i f f e r e n t for  toa l l  of either  the species,  species but t o the h a b i t a t ,  both. A source o f e r r o r o f course, s t i l l  d i f f e r e n t i a l wandering different habitats. obtained  that  negligible observed  this  factor  exists  i n possible  of individuals of a given species i n  I t i s assumed from constitutes  contributing  the trapping results  forpractical  purposes,  to the r e l a t i v e  a  distributions  here.  F i v e s m a l l i s l e t s were t r a p p e d o f f i n a n a t t e m p t t o measure t h e r e l i a b i l i t y arriving  o f t h e q u a d r a t methods u t i l i z e d i n  a t per acre densities  Islets  first  comparable t o  and w h i c h were s m a l l enough t o be  c o v e r e d by t h e t r a p s a v a i l a b l e .  of the i s l e t s  U n f o r t u n a t e l y two  s e l e c t e d were so t r a m p l e d  s e t t i n g t r a p s t h a t no v a l i d islet  island.  were s e l e c t e d w h i c h b o r e h a b i t a t s  t h o s e on t h e main i s l a n d completely  on t h e main  by o p e r a t o r s  r e s u l t s were o b t a i n e d .  Another  w h i l e b e a r i n g o l d s i g n , y i e l d e d no m i c e o r shrews when  trapped.  The f o u r t h b o r e no s i g n and s u b s e q u e n t  trapping  45proved  that  remaining Microtus. forest  i t was u n i n h a b i t e d b y s m a l l mammals.  islet  b o r e no b e a c h  The  d e b r i s a n d h a r b o r e d no  I n a d d i t i o n t h e meadow, muskeg, and c o n i f e r o u s  p r e s e n t were n o t l a i d  out i n d i s t i n c t  p a t t e r n s as  t h e y were o n Goose i s l a n d p r o p e r .  I n a l l a m e a s u r e d 5600  square y a r d s c o n s t i t u t e d  area.  i t s total  t h i s was i n s p a r s e s p r u c e - h e m l o c k of Gaultheria.  Fifty  percent o f  f o r e s t w i t h a sub c l i m a x  T h i r t y p e r c e n t was i n muskeg, r e p r e s e n t e d b y  a s t r i p a l o n g t h e e a s t s h o r e w h i c h was v e g e t a t e d  predominantly  by  a t the north  sphagnum moss a n d l e d u m .  Two s m a l l h e a d l a n d s  and  s o u t h were c o v e r e d by C a l a m o g r o s t i s w h i c h a l s o  the  ledum s t a n d a t t h e s e a t h u s  20 p e r c e n t o f t h e t o t a l The of  islet  about  b y a p p r o x i m a t e l y 400 y a r d s  t o t h e w e s t , and by a d e e p r o c k y  30 y a r d s i n w i d t h o n t h e e a s t .  sea beach  a l l times  The g o r g e  and sandy s e a beach  headland  about  30 f e e t  the d i r e c t i o n o f t r a v e l  crossing  the l i n e . islet  l i n e of traps covering a  i n width.  indicate  intervals  inundated  a t t h e s o u t h e r n e x t r e m i t y was  e f f e c t i v e l y b l o c k e d by a b u f f e r  The  were  completed  except during p e r i o d s o f extremely low t i d e .  An u n t r a p p e d  neck o f land  gorge  L a r g e expanses o f s a n d y  t o t h e n o r t h and deep w a t e r t o t h e s o u t h  the i s o l a t i o n . at  representing approximately  a r e a a s meadow h a b i t a t .  was w e l l i s o l a t e d  sandy s e a b e a c h  bordered  T r a p s were a r r a n g e d t o  o f any s m a l l mammal  was s a t u r a t e d b y t r a p s s p a c e d  at five  caught  yard  and t r a p p i n g was c o n t i n u e d f o r a t w e l v e d a y p e r i o d  w h i c h commenced J u n e 9 and was t e r m i n a t e d J u n e 20.  No  44. animals  were t a k e n a f t e r  inhabiting  J u n e 16 and t h e t o t a l p o p u l a t i o n  t h e a r e a was c o n s i d e r e d t r a p p e d o f f .  A total  o f t e n P e r o m y s c u s was c a u g h t  seven males and t h r e e f e m a l e s .  r e p r e s e n t e d by  Seven Sorex  taken  r e p r e s e n t e d b y f o u r m a l e s and t h r e e f e m a l e s . in  both  either  c a s e s t h e r e was no s i g n i f i c a n t sex, i n d i c a t i n g  were  Statistically,  preponderance  i n t h e case o f Sorex,  of  that population  d y n a m i c s may n o t h a v e b e e n c o m p a r a b l e t o t h o s e o n t h e m a i n island. The islet per  densities  indicated  calculated  from  the data gathered  13 P e r o m y s c u s p e r a c r e , a s compared t o 18  a c r e on t h e main i s l a n d ,  and n i n e S o r e x  p e r a c r e as  compared t o 13 o n t h e m a i n I s l a n d .  The f i g u r e s  islet  accurate..  may be r e g a r d e d  doubt t h a t caught.  every  on the  as reasonably  f o rthe small I have  little  s m a l l mammal v u l n e r a b l e t o t r a p p i n g was  I am e q u a l l y c o n f i d e n t t h a t  no i n f l u x h a d t a k e n  place. The  agreement o b s e r v e d  between main i s l a n d  p o p u l a t i o n d e n s i t i e s may j u s t i f y , a r b i t r a r y methods u t i l i z e d . i n from  outside the p l o t s  Limited replications,  ratios,  varied habitat  that in  t h e unequal  size  t o some e x t e n t , t h e  t h e a r e a s where a n i n f l u x  presented  error.  and i s l e t  such  a grave  differences  source o f  i n a b s o l u t e sex  d i s p e r s i o n and the strorg p o s s i b i l i t y o f t h e l a n d masses had e x e r t e d  differenc  r e a c t i o n i m p l y , however, a need f o r c a u t i o n . The  data presented here  the e x i s t i n g  possibilities  serve i n d i r e c t i n g  of testing  attention to  s m a l l mammal  census  methods o n B r i t i s h C o l u m b i a ' s  coastal  islands.  O u t l i n e o f Mammalian F a u n a o b s e r v e d The  t e r r e s t r i a l mammalian f a u n a o f t h e Goose I s l a n d s a t  t h e t i m e o f s t u d y was r e s t r i c t e d mammals.  species of small  L a s i o n y c t e r i s n o c t i v a g a n s and  yumanensis.  That was  to five  T h e s e were P e r o m y s c u s m a n i c u l a t u s , M i c r o t u s  l o n g i c a u d u s , Sorex" o b s c u r u s , Myotis  o n t h e Goose I s l a n d s  a s p e c i e s o f C a s t o r h a d once i n h a b i t e d  apparent  cuttings.  from  e v i d e n c e i n t h e form  No f r e s h  sign or l i v e  s p e c i e s i s assumed a s C a s t o r Marine  the i s l a n d s  o f dam* s h e l l s a n d  a n i m a l s was o b s e r v e d .  The  canadensis.  mammals r e c o r d e d d u r i n g t h e t i m e o f s t u d y  Included Balaenoptera physalus. Megaptera novaeangliae. Phocoehoides  dalli.  and P h o c a v i t u l i n a .  Eunetopias That  jubata, Callorhinus  other species occur i s h i g h l y  p r o b a b l e b u t none was o b s e r v e d . Marine  mammal s t u d i e s were c o n f i n e d t o o b s e r v a t i o n s o f .  d a t e , p l a c e o f o c c u r r e n c e and a r e p r e s e n t e d as such i n t h i s paper;  no d i s c u s s i o n o f d i s t r i b u t i o n  inexplicable  i s presented.  r e a s o n , m i n k a n d o t t e r a p p a r e n t l y do n o t o c c u r  u p o n t h e Goose I s l a n d s .  No i n d i c a t i o n o f t h e i r  presence,  i m m e d i a t e , o r i n t i m e p a s t was f o u n d b y o u r f i e l d L o c a l f i s h e r m e n , t r a p p e r s and I n d i a n s s t a t e have never or  seen i n d i v i d u a l s  i n immediately  British  F o r some  Columbia  of either  adjacent waters. Game D e p a r t m e n t  Pers.Comm.) a n d t h e i s l a n d  flatly  party. that  they  s p e c i e s on. t h e i s l a n d s ,  No r e c o r d e x i s t s i n  f u rreturn f i l e s  i s not included  (H.Rose,  on a r e g i s t e r e d  4 6 .  trap  line  a s many o t h e r  coastal islands are.  W i t h the p r o x i m i t y Broken  I s l a n d s , and B a r d s w e l l  numerous r e c o r d s It  of otter  on t h e  g r o u p , and i n l i g h t o f  from these  neighboring  islands,  i s p u z z l i n g I n d e e d t h a t some r e c o r d o f o c c u r r e n c e  b e e n made. fishermen A  of l a r g e mink p o p u l a t i o n s  The Goose I s l a n d s a.re u t i l i z e d the year  scarcity  'round and b y l o c a l  of human o b s e r v e r s  has not  by salmon and cod  sportsmen  i n the f a l l .  d o e s n o t a p p e a r t o be t h e  answer. Ample shore  food  f o r both  f i s h e s abounds  s p e c i e s i n t h e form  i n the c o a s t l i t t o r a l  of craba and  o f the Goose  DISTRIBUTION OF SPECIES OF MAMMALS OF GOOSE  Islands.  ISLAND  IN TERMS OF HABITAT OR FLORAL ASSOCIATIONS Castor  canadensis Beaver populations  mature c o n i f e r o u s f o r e s t w a t e r was a v a i l a b l e . R i v u l e t s bordered forest  had a p p a r e n t l y been r e s t r i c t e d a n d muskeg h a b i t a t s where  No e v i d e n c e  by g r a s s e s  was f o u n d  and I n t r u d i n g  f r o m t h e meadows o f t h e l a g o o n  t o the  sufficient  i n other h a b i t a t s . into  the coniferous  were dammed a t t h e f o r e s t  edge. Laslonycterls Few  o b s e r v a t i o n s were r e c o r d e d  Goose I s l a n d . the  noctlvagans  In a l l cases  immediate v i c i n i t y  this  f o rsilver-haired  b a t s on  s p e c i e s was s e e n o n l y i n  o f t h e u p p e r mature c o n i f e r o u s  canopy.  Mature c o n i f e r o u s f o r e s t a f f o r d e d t h e o n l y a v a i l a b l e r o o s t i n g sites  f o r species of bats  on t h e s e  islands.  46A. M y o t i s yumanensis T h i s s m a l l s p e c i e s o f b a t was observed f o r t h e most p a r t i n t h e immediate v i c i n i t y o f t h e c o n i f e r o u s f o r e s t .  On  s e v e r a l o c c a s i o n s however i t was seen f o r a g i n g over t h e c o a s t littoral,  sandy s e a beach and meadowr h a b i t a t s .  Peromyscus m a n i c u l a t u s Peromyscus were found o c c u p y i n g e v e r y h a b i t a t b e a r i n g cover which o c c u r r e d upon t h e Goose I s l a n d s .  Individuals of  t h i s s p e c i e s were more e v e n l y d i s t r i b u t e d throughout t h e h a b i t a t s t h a n were M i c r o t u s and Sorex.  Of t h e 136 a d u l t  Peromyscus t a k e n i n t h e c o u r s e o f t h e quadrat works 46.79 p e r c e n t were caught i n beach d e b r i s , 25.5 p e r c e n t were t a k e n i n t h e c o n i f e r o u s f o r e s t , 17.38 p e r c e n t i n t h e muskeg and 10.29 p e r c e n t i n t h e meadow ( F i g . 2 5 ) . Calculated per acre density estimates f o r t h i s species based on t h e methods p r e v i o u s l y d i s c u s s e d a r e as f o l l o w s : — Beach d e b r i s , 56; mature c o n i f e r o u s f o r e s t , 25; muskeg, 18; and meadow h a b i t a t , 12. Microtus longicaudus M i c r o t u s were t a k e n i n a l l v e g e t a t e d h a b i t a t s w i t h a s t r o n g p r e f e r e n c e f o r meadow i n d i c a t e d .  Thirty adult  47. a n i m a l s t a k e n were d i s t r i b u t e d beach in  debris,  as f o l l o w s : —  13.33 p e r c e n t i n  06.67 p e r c e n t i n c o n i f e r o u s f o r e s t ,  musket and 70 p e r c e n t i n t h e meadow h a b i t a t Per acre d e n s i t i e s o f t h i s  4 i n beach  debris,  10 p e r c e n t  (Fig.  25  ).  s p e c i e s were e s t i m a t e d a t  2 i n t h e mature c o n i f e r o u s f o r e s t ,  3in  t h e muskeg, a n d 18 i n t h e meadow h a b i t a t . Sorex  obscurus Sorex  tation.  were a l s o  Fifty  adult  caught  i n every h a b i t a t  a n i m a l s were t a k e n o n t h e q u a d r a t s :  27.78 p e r c e n t o f t h e s e were i n b e a c h the mature c o n i f e r o u s f o r e s t , and  debris,  density  a c r e i n t h e beach  (Fig. 25).  estimates indicated  debris,  11.11 p e r c e n t i n  11.11 p e r c e n t i n t h e muskeg,  50.00 p e r c e n t i n t h e meadow h a b i t a t Calculated  b e a r i n g vege-  13 S o r e x p e r  5 i n t h e mature c o n i f e r o u s forest',  5 i n t h e muskeg, and 23 i n t h e meadow h a b i t a t . Balaenoptera Six  physalus  fin*»back w h a l e s were o b s e r v e d , t h e f i r s t  Two were o b s e r v e d two  t o g e t h e r o n J u n e 13, one o n J u n e 15, and  a t w i d e l y s e p a r a t e d p o i n t s o n J u n e 26. The  littoral in  o n May 30*  animals waters  o b s e r v e d o n May 30 a n d J u n e 15 were i n t h e o f Goose I s l a n d ,  p e l a g i c waters  One  were  observed  a p p r o x i m a t e l y 14 m i l e s t o t h e - w e s t . a t t h e  edge o f a s h a l l o w a r e a t e r m e d Megaptera  t h e remainder  t h e Goose I s l a n d  banks.  novaeangllae humpback w h a l e was o b s e r v e d  i n coast l i t t o r a l  waters  on J u l y 31. Phocoenoides Dall's  dalli p o r p o i s e was f i r s t  o b s e r v e d o n J u n e 25.  Prior to  FIGURE 25. - R e l a t i v e Abundance Mammals Island  i n Four Habitat B.C.,Summer,19^8.  of Small  T y p e s o n Goose  701  1  I BEACH DEBRIS 2 CONIF- FOREST 3 MUSKEG 4 MEADOW  Lf. j 0  0  1  , 50 • 4030 IO200-  II.  PEROMYSCUS  7060so40\  MICROTUS  30-' 20I00-  70 60 SO 40 , ~ ~ 3020100 -  SOREX  48.  that date none had been seen despite a constant v i g i l maintained i n view of c o l l e c t i n g specimens.  One June 26,  a school of eight was seen i n the l i t t o r a l waters on the east side of Goose Island.  From July 8 u n t i l we l e f t the  islands at the end of August, several schools, numbering from three to twenty individuals occurred almost d a i l y i n Queen's Sound. These animals remained close to the east side of the Goose Islands i n the early and mid morning period.  At t h i s  time -they appeared p l a y f u l and disported r e a d i l y i n close proximity to the prow of the boat.  Later i n the day, the  schools appeared to break up and proceeded to the central part of the sound.  At t h i s time they generally avoided the  boat and were more d i f f i c u l t  to approach.  Advantage was taken of these habits i n securing  specimens  and photographs. Despite comparable time spent i n pelagic waters only one occurrence was recorded f o r the species i n that habitat. A school comprised of eight individuals was observed 18 miles to the south of Goose Island i n an area termed the South bank.  A l l other observations were made i n coast  l i t t o r a l waters.  No animal of the 140 Dall's porpoise  recorded i n the course of t h i s work d i f f e r e d i n size to the extent that i t could have been placed i n a separate age c l a s s . That i s to say, the animals observed were apparently a l l adults.  49 Eumetopias Four  jubata sea l i o n s  observed i n the coast l i t t o r a l  Goose I s l a n d i n May were p r o b a b l y w a n d e r i n g nearby W h i t e f l i f f  species i n p e l a g i c waters  from  This  animal>  trolling  Callorhlnus  animals  from  r e e f vrtiere a r o o k e r y h a r b o r i n g bet?/een 3 0  and 40 i n d i v i d u a l s i s s i t u a t e d .  bank.  waters o f  A single observation of the  was made on J u n e  a large b u l l ,  26 a t t h e s o u t h  was r o b b i n g c o h o e s a l m o n .  gear o f fishermen operating  i n the area.  ursina  Two s m a l l f e m a l e f u r s e a l s were s e e n o n May 18. a n i m a l was o b s e r v e d i n p e l a g i c w a t e r s s o u t h west o f Goose I s l a n d . actively  and a p p e a r e d  was of  seen r e s t i n g Gosling  Phoca  a p p r o x i m a t e l y 18 m i l e s  T h i s i n d i v i d u a l was  t o be m i g r a t i n g .  v a t i o n was made i n c o a s t  littoral  on the water  swimming  The s e c o n d  obser-  w a t e r s , where a n a n i m a l  a p p r o x i m a t e l y two m i l e s west  rocks.  vitulina Adult h a i r  s e a l s were p r e s e n t i n t h e c o a s t  w a t e r s o f Goose I s l a n d t h r o u g h o u t t h e p e r i o d was  One  observed i n p e l a g i c A female  t i d e on August  o f study.  None  waters.  and two pups were s e e n i n t h e l a g o o n a t h i g h 11, and a y e a r l i n g  M a r t i n i n t h e same a r e a o n A u g u s t specimen  littoral  c o n t a i n e d the remains  species of perch.  f e m a l e was c o l l e c t e d b y 12.  The s t o m a c h o f t h i s  o f small f i s h  identified  as a  50. GENERAL DISCUSSION OF OF Castor  OBSERVED DISTRIBUTION  TERRESTRIAL MAMMALS UPON THE  GOOSE ISLANDS  canadenaia  A  series  o f a n c i e n t washed o u t b e a v e r dams was  t h e weat c e n t r a l time,  THE  blocked  considerafcle  muakega o f t h e  the  rivulets  extent,  Along i n g the  the  eaatern  muskeg and  connecting  apparently  s h a l l o w water to s u p p l y  island.  the  These had,  v a r i o u s pot  forming  bodies  needs of the  through  the  at  the  the  of  h a b i t a t , o r perhap8, t o a l a t e r  I t was these  eroua  Impossible  animals  A limited  of  number of  sub  of  The  optimal  diapersed such  some d i a t a n c e compriaed  to d e t e r m i n e  were d i s t r i b u t e d  fringe.  a widely uala  ravages  suitable  dam  probably  p e r i o d of  occupancy.  habitats  c e n t r a l muskega p r o b a b l y a t one  p o p u l a t i o n of considerable  chief  aources  of food  and  Judging  a  larger  have  supported  size.  Indlvid-  a p o p u l a t i o n w o u l d have b e e n f o r c e d to  their  conif-  presented  time  extent  occupied.  e x i s t e d i n the  f o r the h e m l o c k , r e d c e d a r  to  for their construction  two  site8  r a n g e , and. may  i n the  a c c u r a t e l y t o what  i n the  had  muskeg, t h e c o a s t a l  t i m e , due  more s u b s t a n t i a l m a t e r i a l s a v a i l a b l e  in this  area  the  a  atreams d r a i n -  coniferous forest  U n l i k e t h e dams o f t h e  s t r u c t u r e s have w i t h a t o o d  to  relatively  b e e n dammed forming' s e v e r a l s m a l l , d e e p b e a v e r ponda coniferous forest.  one  holes  of  on  s p e c i e a.  8hores o f t h e l a g o o n ,  paasing  found  forage  jack pine from the  which cuttings  observed. The  coniferous habitat u t i l i z e d  more n e a r l y o p t i m a l Ialanda.  range f o r t h i s  appeara  to have b e e n t h e .  s p e c i e s upon t h e  Gooae  51. F o o d was  available  probably  enhanced by  substantial those  on  appeared  and  closer  t h a t the  less  appeared  sites  stand  perhaps,  i n this Factors  beaver not of  leading to the  s p e c i e s on i t  s p e c i e s had  to  s i g n on 1936  be  argued  optimal  sign,  abundance of large  range.  interior, last  of beaver  from  never  and  and  been observed myself  myself  sign presents  that these  by  the  fully conventional  The  precarious  be  do  tenure  elaborated  here.  are more v u l n e r a b l e nature  than  are  range.  existed  other  evidence as  found  the  the  coastal  islands of  did). M c C a b e  these  first  The that  a  optimal  Islands,  habitats represent marginal  In  extant  (1948).  optimal or near  t h e h a b i t a t s on  i n 1948.  s t i l l  possibilities; on  upon  considerable-fresh",and o l d  and  found  two  t h a n was  o n m a n y of  found  on C a l v e r t I s l a n d ,  range represented  be  other  or b i o l o g i c a l  to a greater extent  p o p u l a t i o n once  second,  had  that the h a b i t a t s occupied  P r i n c e s s Soyal, H u n t e r  H.M.Laing  t h a t may  range need not  climatic  M a r t i n and  populations  edge  of the  say .that s u c h ' p o p u l a t i o n s  Goose I s l a n d s has islands.  i t  made t h e i r  disappearance  a problem  marginal  inhabiting Beaver  those  than  evidence  coniferous forest  of willow, poplar  f o o d s , i t may  a catastrophe of  those  more  "wash o u t s "  From the  than had  represent adequate beaver a  dams w e r e  were  habitat.  I n the l a c k  Buff ice: to  t o be.  that the  Goose I s l a n d s p r e s e n t solved.  The  subject to  at the  been o c c u p i e d more r e c e n t l y indicating  escape f a c i l i t i e s  deeper waters.  probably  t h e muskeg  at hand,  range  and occupied  52.  by  small populations  which are forced  periods  o f time,  lasting  sign .that-is  respects, Inclined islands  until  leaving i n their difficult  an adequate  marginal  true  1904  and deciduous  than on t h e i n n e r  the disappearance o f beaver when M r . Max Loh'brunner  from  directly  or  indirectly,  t h e Goose I s l a n d s .  (1948, P e r s .  t h e i s l a n d s , he observed  digging  f o r clams on a beach a t l o w t i d e .  these animals were i n t h e f i n a l  Comm.)  a number o f e m a c i a t e d  stages  In his  t o r n and bleeding,  the animals  reported  t o have an a i r o f d e s p e r a t i o n  a b o u t them.  can  be i n f e r r e d t h a t  starving  a In  waters.  They h a d ,  clams.  In light  and r e s t r i c t e d  i ti s conceivable  that  habitat  to a  of the limited on so s m a l l  these carnivores  trappers Here  located  again  the beaver  the marginal  possible  that  some t r a p p e r  and subsequently  aspects  o f the area  an  may h a v e  f a c t o r c o n t r i b u t i n g t o the disappearance o f beaver addition i t i s entirely  who  Certainlyi t  beaver would rate'more h i g h l y  dog than would  escape f a c i l i t i e s island,  i n surrounding  ribs  were  been abandoned on t h e i s l a n d s by Indians to fish  dogs  opinion  of starvation;  their  come a n n u a l l y  About  first  showing,  apparently,  growth  islands.  visited  feet  the coastal  especially f o r the  f r e s h water  Man may h a v e b e e n i n s t r u m e n t a l , in  am  range f o r beaver.  concept holds  much more l i m i t e d  I n these  h a s b e e n made, I  and t o regard  as marginal  Goose I s l a n d s , where area, are  study  c  This  wake a n abundance o f  t o age a c c u r a t e l y .  t o agree w i t h M Cabe on t h e whole  t o r e - e s t a b l i s h over  trapped would  been  there. or them o f f .  facilitate  53. annihilation. In of  any  event,  the  a living  animal  from  The  local  never  of  Why  there  their  From Mr. that  beaver  occupied  the  islands  to r e - e s t a b l i s h  coastal  46  years  islands  once f o r c e d an  augmented t r a p p i n g along  ing  reduces  the  occupancy and  hand  original  sequently disappeared ment as  seems t o  length of Goose  no  to and  which  t h a t may  and  elapsed  con-  marginal individuals  inner thus  have  eliminat-  the  accidently  In this  the  other and  sub-  of  the  environ-  case  any  future  possibly  be  temporary,  explanation for  since beaver  islands  l e d to  On  inadequacies  on.  to  of  restocking.  a more p l a u s i b l e has  left  a  i t i s possible that  have a r r i v e d  so  1904.  over  surplus animals,  such  assumed  to  east are  coast  p u r e l y t o c h a n c e , may  furnish  time  the  lived  upon  the  Mvotis  were  con-  islands.  Lasionycteris  noctivagans  Population fined  may  l a n d mass, f o o d ,  occupancy i s l e f t and  the mainland  due  prior  m u s t be  b y man,  additional  stock  safely  extensive wandering  number o f  original  be  themselves  to the  a possible population pressure  the  exist.  sportsmen i n t e r v i e w e d have  some t i m e  when p o p u l a t i o n s were u n m o l e s t e d  annually  to  t h e B.C.Game D e p a r t m e n t h a s  approaching  I f the  r a n g e vrtiich  and  and  L o h b r u n n e r » s r e p o r t s i t may  of time  jecture.  the Goose I s l a n d s a p p e a r s  record  occurrence.  they have f a i l e d  period  a p p a r e n t l y a r e g o n e , no  trappers, fishermen  s e e n them  records  beaver  to n i g h t l y  studies of Lasionycteris observations  and  to  and  some f i e l d  collecting.  54 The period  silver-haired  o f almost  b a t was r e c o r d e d  continual nightly  f r o m May 23 t o J u l y 2 1 . male c o l l e c t e d servation. last  One  observations  observations  times  extending adult  constituted the f i r s t  were s u b s e q u e n t l y  i n a  ob-  recorded,  the  on June 30. I n a l l cases  evening  than  this  species  d i dMyotis.  above t h e upper only apparent  The  food  during  activities  earlier  I t fed at a high  was a s p e c i e s  prevailing  the night  appeared  i nthe  level usually  canopy o f t h e mature c o n i f e r o u s  became a c t i v e i n t h e l a t e  for  five  s p e c i m e n was t a k e n , a n  on June 12 w h i c h  Four  only  of small white  forest. moth  The  which  afternoon.  w e s t e r l y winds that o f t e n blew  t h e summer m o n t h s p r o b a b l y  and d i s t r i b u t i o n  of this  the l a c k o f an appreciable  species  throughout  influenced the a n d may  account  p o p u l a t i o n upon t h e Goose  Islands.. Myotis  yumanensis  In  t h e same p e r i o d o f o b s e r v a t i o n m a i n t a i n e d f o r  Lasionycteris recorded. 1 13  24 o b s e r v a t i o n s  Five  specimens were  immature male. mm.  on May  of the L i t t l e collected,  A female taken  vations,  s t i l l  present  4 a d u l t females and  June 1 c a r r i e d  i n crown-rump measurement. 23 and were  brown b a t were  Myotis  a n embryo  were o b s e r v e d  on the l a s t  day o f obser- -  J u l y 21.  This  species  Lasionycteris. coniferous  appeared l a t e r  i n the evening  than d i d  I t f e d g e n e r a l l y below the canopy o f the  forest,  flying  low along  just  t h e edge o f  through  55. clearings  i n the  trees.  prevailed  I t was  observed  the  sea,  feeding  skimming  low  On  s e v e r a l o c c a s i o n s when no .wind-  at  over  d i s t a n c e s up  t h e w a t e r and  a p p a r e n t l y upon f l y i n g  w h i t e moth u t i l i z e d  by L a s i o n y c t e r i s was  On  other occasions myotis  sandy sea  b e a c h e s and n e i g h b o u r i n g  Compared t o t h e m a i n l a n d  Myotis was was  much h i g h e r  is  some k i n d .  due  to wind e f f e c t  than, t h o s e  that this  the h i g h  the  flying,  p r o b a b l y has Previous  forest an  o f the  little  were o b s e r v e d  meadows a b o u t t h e inner i s l a n d  as i n t h e  bat  larger  bat.  this the  lagoon.  populations  vd.th t h e  as w e l l a s  case o f L a s i o n y c t e r i s .  heavy p r e v a i l i n g  This  apparently  seems t o  a b i l i t y or  The  preference  above i t o r a l o n g  the  e f f e c t upon the d i s t r i b u t i o n o f t h i s  observations  along  w i n d s are than  the  c o a s t and  I n h a b i t e d by  the  low to hunt edge, species.  Areas a f f e c t e d  by  much s m a l l e r popu-  of bats  sheltered areas,  Myotis  a p p e a r t o be much more g e n e r a l l y d i s t r i b u t e d Columbia than  than  coastal islands,  lations  coastal British  are  This  i s i n f l u e n c e d l e s s by w i n d  seem to s u b s t a n t i a t e t h e s e c o n c l u s i o n s .  out  The  over  open f e e d i n g L a s i o n y c t e r i s .  f l y i n g h a b i t coupled through  reefs,  a l s o t a k e n by  p o p u l a t i o n s on Goose I s l a n d h o w e v e r , a r e  indicate  over  p o o r l y r e p r e s e n t e d u p o n t h e Goose I s l a n d s .  probably  Myotis  and  yards  about exposed  insects of  species.  t o 150  and  species  i s Lasionycteris.  of  through-  56, Peromyscus It  manlculatus  i s g e n e r a l l y conceded  closely  related  i n g s t h a n do  forms range  females.  d i f f e r e n c e was difference  m a l e s and  farther  .05  level  of total  research.  61 were f e m a l e s .  trapped.  I f one observed  preponderance  However, t h e  studied  critically  i n this  c o a s t where t h e e c o l o g i c a l  this  wanderalleged  significant observed  sex r a t i o  generaliz-  would i n d i c a t e  s p e c i e s has  r e s p e c t on t h e B r i t i s h  never  c o n d i t i o n s v a r y g r e a t l y from  preponderance  each h a b i t a t  no  alternative  and  that  an  reflected  these h a b i t a t s ,  I  may  this  species i n a l l habitats  ratio  Statistically,  attached to t h i s i s a c c e p t e d and  Peromyscus m a n i c u l a t u s The  beach  s t u d y was  observed  h o w e v e r , no  r e g a r d e d as n o r m a l inhabiting  be a t t r i b u t e d  Islands. of  o f a g r e a t e r range  difference  i n the  significance  so a b a l a n c e d  An  sex  Islands.  species f o r the  t o a number o f e c o l o g i c a l  beach  factors.  a f f o r d s a!wide v a r i e t y o f f o o d s a t the s e a s o n made.  14  for populations of  t h e Goose  apparent p r e f e r e n c e o f t h i s  d e b r i s may  o n t h e Goose  sexes  d i f f e r e n c e , a preponderance  be r e g a r d e d a s t h e r e s u l t  male o f t h e s p e c i e s . c a n be  see  o t h e r than t o accept the f i g u r e s a t f a c e v a l u e  I n o t h e r words, t h e o b s e r v e d males,  those  insignificant  catch i s generally  i n each p l o t w i t h i n  been  studies  t o assume t h a t : t h e y r e p r e s e n t t h e d i s t r i b u t i o n o f  throughout  The  o f the f a c t  o f males i n the t o t a l  in  and  I n view  a  Columbia  o f e a s t e r n N o r t h A m e r i c a , where most o f t h e P e r o m y s c u s have been conducted.  in  S e v e n t y - f i v e were  i s to accept the  a t i o n p o s t u l a t e d above,the of females.  No  o f p r o b a b i l i t y was  animals  s p e c i e s -and  i n their nightly  methods o f m e a s u r i n g  possible, i n this  at the  t h e sex r a t i o  No  that males o f t h i s  a b u n d a n c e o f v e g e t a t i v e f o o d s was  this  growing  57. on  t h e h i g h beach.  being u t i l i z e d  Lathyrus,frotentilla  by P e r o m y s c u s .  which t h e droppings o f t h i s traps  C u t t i n g s ?/ere f o u n d  beetles  s p e c i e s were o b s e r v e d ; a n d  and o t h e r i n s e c t  direct  l i f e was a l s o  evidence i n d i c a t e d  habitat. habitat  Limpet  o f amphipods  a potential  supply i n t h i s  were f o u n d w h e r e v e r t h e  of coastal  a v a i l a b i l i t y o f d r y home s i t e s  Peromyscus. i s i d e a l on t h e h i g h  a n d w h i l e no p r e d a t i o n a p p a r e n t l y e x i s t s ,  facilities fulfilled  i n t h e maze o f i n t e r w o v e n  escape  l o g s may p o s s i b l y  some I n h e r e n t n e e d o f t h e s p e c i e s h e r e .  sphagnum i n abundance may h a v e . b e e n u t i l i z e d material.  Dry  f o r nesting  as play...._ I b e l i e v e  this  activity  P e r o m y s c u s t a k e s t h e f o r m o f unimpeded romps o v e r o f ground.  T r a c k s i n t h e sand  s e r v a t i o n s w o u l d so i n d i c a t e , the beach This  open  and p r e v i o u s ob-  a t any r a t e .  I f this  i s true,  a f f o r d s r u n n i n g grounds o f u n s u r p a s s e d e x c e l l e n c e . combination  o f abundant a n d v a r i e d  a v a i l a b i l i t y of nesting sites, materials, facilities, dryness  have  M o s t s p e c i e s o f mammals i n d u l g e i n a c t i v i t i e s  w h i c h may b e i n t e r p r e t e d  stretches  While  o c c u r r e n c e a n d t h e s e may b e r e g a r d e d  as a r e g u l a r p a r t o f t h e d i e t  beach,  i n abundance.  the u t i l i z a t i o n  and c r a b remains  favored their  The  Additional  o f a m p h i p o d s , c r a b s , l i m p e t s and a h o s t o f  as f o o d b y P e r o m y s c u s t h e y do f o r m  in  about  s e t i n such p l a c e s i n v a r i a b l y y i e l d e d mice.  f o o d i n t h e form  no  and V i c l a  open ground  at this  food  supply,  and escape  f o r p l a y coupled with the g e n e r a l  season,probably  accounts  p r e f e r e n c e o f Peromyscus m a n i c u l a t u s  f o r the apparent  f o r beach  debris habitat  58. on  t h e Goose I s l a n d s . Fresh sign  i n the form  of droppings  s i g n was  was  the beach d e b r i s .  Old  c o u r s e , i n t h e wet  c o a s t a l b e l t , must be w e l l s h e l t e r e d i n  o r d e r t o l a s t more t h a n a few humidity w i l l  lacking.  v e r y abundant i n  hours.  Mouse d r o p p i n g ,  The  high  cause d e t e r i o r a t i o n i n a v e r y  relative  s h o r t time  when s u c h d r o p p i n g s  a r e p r o t e c t e d from  Careful  i n the d r y e r r e c e s s e s however,  examination  r e v e a l droppings m a t e r i a l may droppings lasting  identified  a r e a c c o m p a n i e d by  sign of this nature  d e f i n i t e l y whether or not previous winter,  ^o  and  The  abundance o f f r e s h  w e l l be  not  and  s i g n was  s i g n was  absent  at other  of fresh  far  I do m a i n t a i n  experienced  That  the. beach  seasons  in  o f the  t r a c k s i n the  than  seems q u i t e  While  t h a t , by  year.  sand,  :I; do  careful  o p e r a t o r can v e r y o f t e n  Peromyscus u t i l i z e d  greater extent  the year  i n the  state  much s i g n one mouse l e a v e s i n a  g u i s h between an a r e a g r e a t l y u t i l i z e d not.  c u t t i n g s and  made d u r i n g  found  such  s u b s t a n t i a t e s the t r a p p i n g  Myriads  p r o f e s s t o know how  an  When  runways o f P e r o m y s c u s were much more i n  g i v e n l e n g t h o f time,  is  sign.  than i n the other h a b i t a t s s t u d i e d .  examination  sometimes  t h a t the p o p u l a t i o n present  sign-  r e s u l t s obtained here;  evidence  rainfall.  i t i s o f t e n p o s s i b l e to  winter  May  as w i n t e r  runways, g r a s s  the  debris habitat, indicating  f r e s h droppings  even  -- w h i c h , when compared t o t h e more r e c e n t  o f t e n be  J u n e may  direct  of  by m i c e and  one  which  the beach d e b r i s to a  the o t h e r h a b i t a t s at t h i s  apparent.  distin-  time  of  59. The  trapping  indicated  again  s u b s t a n t i a t e d by  that u t i l i z a t i o n of  P e r o m y s c u s was Winter  data,  less  by h a l f ,  s i g n , however, i n the  a b u n d a n t on to f i n d .  the  forest  coniferous  forest  by  t h a n i t was  In the  beach d e b r i s .  f o r m o f cone c u t t i n g s was  floor  That a h e a v i e r  while  f r e s h s i g n was  p o p u l a t i o n had  t h i s h a b i t a t appeared obvious. ly  sign,  previously  First,  Increment o f young a n i m a l s b o r n i n the  that  the  part,  and  those  p o p u l a t i o n had  representing  a decline resulting  by  population  represent,  periods  the  These h a b i t a t s covered  tides,  The become  great  storms  coniferous  forest  p o p u l a t i o n d e c l i n e may  coniferous  i n these  limited  and  a f a r greater  b e a c h d e b r i s and  amount o f e v i d e n c e  surviving  sea  and  possibly  the u n i v e r s a l d i s p e r s a l o f winter  observed throughout the  observed i n the  recently  optimal.  concept of recent  be v a l i d a t e d by  a  a l l habitats,  populations  of high  in  Second, t h a t  beach d e b r i s .  growth, i n which case the  muskeg become more  meadow and  i n heavier  i s that habitats bordering  untenable during winter  The  recently occupied  range r e p r e s e n t e d  third possibility  limited  winter.  immediate-  fall  a p o s s i b l e p o p u l a t i o n p e a k w h i c h had  i n more o p t i m a l  and  observed populations  which have s u r v i v e d the  much h i g h e r  entered  that the  occupied  annual  summer a n d  months i s f o r c e d i n t o l e s s f a v o r a b l e h a b i t a t s by pressure,  difficult  Three p o s s i b i l i t i e s  come t o m i n d i n t h i s r e s p e c t .  very  sign  muskeg h a b i t a t s .  area  than d i d  the  i t is difficult  to a t t r i b u t e the  areas  the  areas  solely  to  populations  of suitable peripheral habitat.  60. In considering  the high  reproductive  p o t e n t i a l o f the rodents  involved,  however, i t i s e n t i r e l y p o s s i b l e  increment  o f young  universally extent  could,  that  i n a season o f high  productivity,  " f l o o d " t h e a r e a s o f f o r e s t and muskeg t o t h e  i n d i c a t e d by t h e w i n t e r  where t h e l i m i t i n g  sign observed.  On a n i s l a n d  f a c t o r s a p p e a r n e g l i g i b l e i n t h e summer  months, i t seems l o g i c a l  t o assume t h a t  a large part  e v i d e n c e f o u n d c a n be a t t r i b u t e d t o t h e a n n u a l The by  possibility a recent  extent  this  that  f a c t o r Influenced  From a p u r e l y  r e m a i n s . " To what  t h e amount o f e v i d e n c e  from t h e a v a i l a b l e physical point  t h e w i n t e r months.  o f v i e w t h e beach  At this  -  f o r a large part  few f e e t o f d o i n g  increased  ground  eliminates  swell plus  the beach d e b r i s  range f o r small The  so.  t i d e s accomInundates  High winter t i d e s coupled  arrested  Summer  b u t came w i t h i n with  growth, almost c e r t a i n l y  o f Goose I s l a n d  as r e g u l a r  winter  mammals.  coniferous  f o r e s t i n many r e s p e c t s  a p p e a r e d t o be  adequate range f o r Peromyscus.  Home s i t e s  facilities  l o g s , dead t r e e s  fall  from  o f t h e time.  t i d e s f a i l e d a t o j f l o o d the areas i n question, a very  debris  mammals  season, p r o b a b l y  p a n i e d by t e r r i f i c w i n d s -and s t o r m s u n d o u b t e d l y peripheral habitats  found  data.  November t h r o u g h M a r c h , t h e p r e v a l e n c e o f h i g h  the  increment.  meadow h a b i t a t must become u n t e n a b l e t o s m a l l  during  o f the  s u c h e v i d e n c e may h a v e b e e n augmented  decline i n t o t a l population  c a n n o t be m e a s u r e d  and  the annual  i n t h e form o f f a l l e n  are p l e n t i f u l ,  and escape  as i s open ground f o r r u n n i n g .  and windGeneral  61. : dryness  and v a r i e t y  of  food,  a b l y w i t h beach d e b r i s Peromyscus a p p a r e n t l y shed cones floor  at  is  feed  season.  largely  reversed,  ecological  along  the  niches  In winter  upon seeds c u t  changes  dryness  the  of  forest  from  the  then  t h a n do t h e  occurring with  sea  affording washed  it  may be c o n c l u d e d t h a t  the major  seasonal  on the  to  from one h a b i t a t indicates  peripheral habitats  April.  that  i n late  population,  occurs  low w i n t e r  Peromyscus f o r a g i n g  supplement  their  diet  tides  appears  Heavier winter dicated  tidal  f a l l with  interior  increasing  t h e month o f  November  and s t o r m c o n d i t i o n s .  edge t o t h e is  the p e r i p h e r a l h a b i t a t s  In  possibility beaches very  to  real.  regularly,  unlikely.  p o p u l a t i o n s o f F e r o m y s c u s were  thick  one.  d u r i n g t h e month o f  and r e l a t i v e : , c a l m , t h e  i n t h e muskeg h a b i t a t .  p r e v a i l e d under the  a popula-  different  w i t h marine i n v e r t e b r a t e s  extremely  in  p r o b a b l y more g r a d u a l ,  from the f o r e s t  That a p o p u l a t i o n o c c u p i e s however  sometimeis  to  s p r i n g movement from  and c l i m a x e d i n o r a b o u t of winter  leading  a vastly  summer and e a r l y  w i t h the onslaught periods of  to  the  The a u t u m n a l movement  beginning  of  Goose I s l a n d s ,  ecologi-  variation  Peromyscus  The e v i d e n c e  the  two  i n a r e v e r s a l of optimal conditions  t i o n movement  the  forest  probably r e s u l t s range  favor-  coast.  From t h e s e d i s c u s s i o n s cal  compare  summer m o n t h s .  The r e l a t i v e  apparently  more s u i t a b l e habitats  i n the  do n o t  o f P i c e a w h i c h a r e i n abundance u p o n t h e  that  habitats  however,  cover  also  An a b u n d a n c e o f w i n t e r afforded  by  stands  of  insign  Myrica  62. Ledum, d w a r f e d s i g n was taken  Thuja  and  and  only  scarce  i n the  quadrats  arguments presented lations well.  The  animals,  must, i n the hospitable  depletion of theory  only,  ficial  habitat. of  The  In years to  an  the  the  inference here,  i n the  productivity  a l l of  of  the  t h e muskeg, wet  bearing  which  and  i n -  plants.  populations  may and  then,  t o t h e muskegs f o r that  the  evidence  the muskeg i s r e p r e s e n t e d  coniferous forest  the  repro-  coniferous forest,  fact  as  winter  of high  extremely  supply,  by  adequate  support into  o f low  by  food. of  droppings  cone c u t t i n g s were  course,  i s t h a t the  i n d i c a t e s more r e c e n t u t i l i z a t i o n  than  presence  do  the  forest.  p e r p e t u a l wetness of  dryness  limiting  provide  the  the P i c e a seed  i n the  droppings  The  to  i s strengthened  while  cuttings  In years  point of view,  first,  popu-  vary with  them t o f o r a g e  populations using  dominant. of  stages,  winter  h o w e v e r , may  season,present  another  The  the muskeg  prove inadequate  winter  Peromyscus  to  environment d e s p i t e ample seed  move i n two  the  Fresh  habitat.  apply  annually.  population.  forcing  Regarded from  nature.  i n d i s c u s s i n g the higher  total  thus  of  caught i n t h i s  c o n i f e r o u s f o r e s t may  h a b i t a t may  winter  percent  degree of u t i l i z a t i o n  range f o r the  This  similar  i n mature c o n i f e r o u s f o r e s t  duction the  on  17.38  was  number o f y o u n g p r o d u c e d  this  plants of  i n periods  factor A l l of  to  the muskegs, d e s p i t e a  of drouth,  appears  t o be  s t a b l e Peromyscus populations  the  animals  taken  coniferous forest,indicating  i n  super-  the this  were caught n e a r I n t r u s i o n s  t h a t the muskeg p r o p e r  was  63. used  primarily  as a food  summer m o n t h s . intensified which  I n the winter  f o r the general  In light  populations actuality  o f these  recorded  based  Sign ly  percent  taken  were  traversed  adequate  specific  over  was t a k e n  s i g n was n i l .  from  coniferous  was a l m o s t  proper,  of large Microtus  observed.  offering  than  tail  that  appeared  the take  wet and  possible  inter  account f o rthe low  I h a v e no s p e c i f i c  between t h e two s p e c i e s .  complete-:  despite the  Food and homesites  much g r e a t e r u t i l i z a t i o n  i n a l l h a b i t a t s bore  indicating  i n this habitat;  edge t o s e a s h o r e .  i n t h e heavy grasslands runways.  only  A l l o f t h e Peromyscus  c o m p e t i t i o n may i n t h e m s e l v e s  those  were i n  T h e meadows h o w e v e r , w e r e b a s i c a l l y  No i n t e n s i t y  sign  i n n a t u r a l runways formed b y r i l l s  of Microtus  populations  taken  catch  o f c u t t i n g s o r droppings  to support  tolerance  the forest  o f meadow b y P e r o m y s c u s was s m a l l ;  t h e meadows  populations  probably  abundance o f w i n t e r  f o r e s t edge.  and w i n t e r  indicated.  was  i nthe  d i s c u s s i o n s i t seems t h a t t h e  o f t h e quadrat  None was t a k e n  species  inhabiting  i n the coniferous  caught  prevalence  utilization  t h e muskegs,  i n the form  lacking,  by t h i s  as u t i l i z i n g  Utilization 10.29  this  by i n c r e a s e d populations  accounts  found.  foraging area  data  regarding  Many o f t h e P e r o m y s c u s  scars, indicative  o f s c a r r i n g was a p p a r e n t i n meadow  of fighting.  Peromyscus  i n o t h e r h a b i t a t s where M i c r o t u s  d i d n o t abound,  intraspecific  than  interspecific Microtus  intolerance rather  one o f an  nature. were taken  i n some i n s t a n c e s  i n r i l l  sets  that  64. also a  caught Peromyscus which leads  t o the assumption  c e r t a i n amount o f i n t e r m i n g l i n g o f s p e c i e s  No P e r o m y s c u s heavy grass,  catch  i n the confined  however,  Any to  to routes  be  No  Peromyscus u t i l i z i n g  had  home s i t e s  in  t h e muskegs.  forced those  from  Microtus  The  the area  the four  must  feet at months  summer t i d e s  t h e meadow  i n summer  came  probably  f o r e s t edge as was t h e c a s e  the winter  months these  animals  were  f o r e s t a n d m u s k e g s a s m^ere  debris.  i n t h e case o f Peromyscus a balanced throughout the Microtus  a possibility  that  months.  so.  i n the coniferous  t h e beach  Goose I s l a n d .  accepted The  given. <?re  longicaudus  indicated  are  During  during  the higher  i n the coniferous  to forage  As  o f doing  confine  d e b r i s o n t h e meadows a n d  flooding occurred  a few inches  The  the winter  and o t h e r  spent on t h e i s l a n d s , although within  c a n be  a t some t i m e t o a d e p t h o f t w o o r t h r e e such  through  considerable  up t o t h e f o r e s t edge i n d i c a t e s t h a t  flooded  least.  runways  the meadow'permanently^forced  t h e f o r e s t and muskegs d u r i n g  presence o f l a r g e logs  place.  and that Peromyscus  i n which wide berth  Peromyscus u t i l i z i n g  extending  Microtus  seems t o i n d i c a t e t h a t a  degree o f avoidance might p r e v a i l themselves  takes  that  While d i f f e r e n t i a l with  this  species  populations' i n h a b i t i n g wandering  of Microtus  of s u i t a b l e grasses.  between sexes i s  also, the figures  o n t h e same b a s e s - p r e s e n t e d  occurrence  sex ratio i s  obtained  f o rthe former.  i s apparently  The l o w r e t u r n s  correlated  recorded  from  with  beach d e b r i s , c o n i f e r o u s f o r e s t a distinct in  each.  l a c k o f some e c o l o g i c a l These are e a s i l y  where t h e minimum Microtus taken  taken.  and no  Grasses stands  amount Where  i n these  grasses  of their  along  occurred  o n t h e meadows.  was is  was  observecl.  appeared  I n t h e muskegs  though not i n the cover  inhabiting  was  plants.  and t h e d e n s i t y o f t h e g r a s s e s .  of ancient  sphagnum  on t h e muskeg.  which  of  heavy grass materials  The suitable  of the  T h e p r e f e r r e d summer h a b i t a t  stands  plus  t o an optimal  ecological  a f f o r d i n g maximum f o o d ,  suitable  bases f o r burrowing  I n t h e w i n t e r months t h e M i c r o t u s  droppings This  lack of suitable  foods  of winter u t i l i z a t i o n  o l d droppings  That a r e v e r s a l  and,,  combination cover,  of  nesting  and n e s t i n g  p o p u l a t i o n s must  when t h e g r a s s e s  then  preferance  t h e meadows due t o f l o o d i n g c o n d i t i o n s p r i m a r i l y ,  but  by  Perhaps the  forms the base  substantiate the trapping returns.  be a t t r i b u t e d  evidence  thick  provided  t o be t h e a v a i l a b i l i t y  o b v i o u s l y meadow, w h e r e f r e s h c u t t i n g s ,  through  were  F r e s h b u r r o w s were numerous o n t h e meadows, b u t none  found  burrows may  no M i c r o t u s  b a s e o f t h e meadow h a b i t a t i s p r e f e r r e d t o t h e  soggy mass muskeg.  presence  Ample  factors  soil  occurred  regularly  deciding  firm  forest  occurring yielded the only  t h e edges.  mosses and o t h e r muskeg  sites  requirements  e x p l a i n e d f o r beach and  sphagnum  nesting  or  two h a b i t a t s w e r e c o n f i n e d t o s p o r a d i c  and i n t r u s i o n s  observed  habitat indicates  requirement  of grasses  no  indication  however, grasses stands  and muskeg  sites. leave  and p o s s i b l y  are dead.  of coniferous forest  was  No  found,  and runways were p r e v a l e n t upon t h e muskegs.  of optimal  conditions concerning  Microtus  o c c u r s b e t w e e n t h e meadow fall  i s indicated.  coniferous apparent  forest  evidence  habitat.  and muskeg h a b i t a t s  Though  i n winter leaving  little  are n o t pursued  readily  i n discussing  are well  adapted  t h e banks o f r i l l s  travel  w i t h amazing  runways o f f t h e main  stations grasses  by M i c r o t u s  and s m a l l streams. the grass  swim  Long  these  despite their  short  a r e found;  lead  legs.  to feeding  i n other cases the  t o burrows o r other p o i n t s o f  are eaten.  species of grasses  and sedges were being  upon t h e i s l a n d s .  As s p e c i m e n s  unfortunately  run-  along which  thoroughfares  a r e c u t and c a r r i e d  Several  d e s t r o y e d I am u n a b l e  utilized  collected  were  to present the data  here.  stomachs o f a l lM i c r o t u s examined, however, c o n t a i n e d  green  finely  evidence of  respects  t o a wet h a b i t a t , t h e y  rapidity  where t h e c u t t i n g s  cover where they  The  i n many  further.  ways a r e c o n s t r u c t e d t h r o u g h  Side  population  f o r s h o r t d i s t a n c e s and d i g s h a l l o w burrows i n wet  soil- along  animals  or-no. s i g n } t h e  p o i n t s t o muskeg a s t h e p r e f e r r e d w i n t e r  The arguments p r e s e n t e d  Microtus  and  some M i c r o t u s m a y u t i l i z e t h e  movement i n P e r o m y s c u s a r e a p p l i c a b l e h e r e and  i n spring  m a s t i c a t e d mass o f v e g e t a b l e  o f these  animals  eating insects,  M i c r o t u s and Peromyscus were p a r t i a l l y  traps. cases  Sorex  food.  I found  a no  b u t some  specimens  devoured  i nthe  were r e s p o n s i b l e i n p a r t f o r t h i s ,  b u t i n many  rodents had apparently been.guilty; whether Microtus o r  Peromyscus was  undetermined.  Conditions prevailing  o n t h e Goose I s l a n d s i n r e s p e c t t o  67Microtus, coastal  prevail  Islands  longicaudus holds  true  Sorex  and  i s an  w e l l i n many a r e a s , v i s i t e d on on  the mainland.  animal  muskegs  generally  Columbia  sex  ratio  significant (40 m a l e s :  to the  warrants  14  females)  observed  adult  remained  balanced  traps.  indicating  a  sex  data on  observed derance  had  ratio  i n two  catch,  Sorex  had  t o assume t h a t and  so  i n Sorex  factors leading  a f t e r t h e young are  Charlotte  i n  Algonquin  that  of Sorex  the  studied  young were t a k e n i n the  ( h e r e i n r e f e r r e d t o as  been repeated  basic  species  observed  the  already  left  sex r a t i o  on  cases,  Island  the nest were  t h e phenomenon accounted  datum  i n both  When t h e G o o s e  pre-datum p o i n t  of males observed  The  highly  adult  and  Pers.Comm.) r e v e a l s  o f 2 t o 1.  while  seems r e a s o n a b l e  total  ( G u i g u e t , 1946)  o f m a l e s was  i n i t i a t e d young the  The  and  t h e Queen  w o r k was no  taken,  data  c o l l e c t e d on  Here  statistically  explanation.  time,  ratio  forest.  number o f a n i m a l s  u n t i l the f i r s t  a preponderance  i s not  was  however, r e q u i r e s  ratio  After this  coniferous  of males i n the  Jackson,  sex  the  further discussion.  i n B r i t i s h Columbia (M.  of a d u l t male Sorex  to 1 female  preponderance  Ontario  point)  except  small no  review of f i e l d  Islands Park,  of 2 males  due  consequently  A  preponderance  i n a l lh a b i t a t s  significant  sex  That M i c r o t u s  t h e meadows and  i n coastal British  significant  observed  it  of  other  obscurus A  the  as  obtained  previously  f o r the  prepon-  these i s l a n d s .  to the observed,  apparent.unbalanced remain,  as  and  yet  obscure. British  Present, studies being  conducted at  Columbia by M i s s Mary J a c k s o n m a y " c l a r i f y  From the  evidence  breeding  adult  to date i t appears  f e m a l e s may  Some s p e c i e s  of  be  the  shrews a p p a r e n t l y  they breed  turn h e a t o c c u r s  requiring extensive  zation.  be  I t may  sedentary  and  the of  argued  catch  on  Queen C h a r l o t t e  the of  twice  that  the  latter  sex.  datum p o i n t ,  populations  there  may  t a k e n on  caught  e a r l y i n May  vailed  there  the  no  which  the  great  of  the  an  pre  this  preponderance  datum p e r i o d  actuality  of  trapping  i t i s obvious  balanced  sex  ratio  preponderance of In this respect s  to  that  should  females,  the  post-datum  well.  indicate to  this  that  the  end  pregnant  animal  was  same c o n d i t i o n s  pre-  equal  males  number o f  to  and  since  a t t r i b u t e the  I f the  the  year  returns  males  :  ratio  —  in  the  in  t h a n do  the  indicating a reflecting  f a c t o r s remaining sex  were  O n l y one  i n t e r p r e t e d as  other  studied  have been apparent  trapping  be  a  d i f f e r e n t i a l wandering  should as  are  were-lactatIng  wander f a r t h e r throughout  females,  females  par-  f e r t i l i -  females  datum p o i n t ,  c a r r y i n g embyos, i t seems i l l o g i c a l  otherwise  the  o n c e up  and  the  these, females  observed preponderance of males  post  effect  seemed t o  Since to  A  populations  pregnant  Goose I s l a n d s  females were t a k e n p r i o r majority  time  the  in  breeding  active, resulting i n In  respect.  issue.  part.  1946).  discontinued.  and  or  this  of  lower v i a b i l i t y  coitus to  indicating that  i n this  the  d i e . a f t e r one  have bred only  A u g u s t w h e n t r a p p i n g was  f e m a l e was  at  Islands  a  (Asdell,  males extremely  larger  caught a f t e r the  that  answer i n  season i n which  the  the. U n i v e r s i t y  should  a  constant.  probably  be  interpreted  as i n d i c a t i n g a more e v e n l y  that  The s i t u a t i o n  time.  of  females before  The  f a c t remains  after  t h e young  i n respect  that  significantly  undergo habit  that  females  the  w h i c h may  f o r every  observed If  a f t e r breeding  manifested  2 males  Goose I s l a n d s  male  only  are observed  On  1  9 adult this  It.i s entirely  become more similar  cautious,  reversal i n  catch. returns  greater  On  catch  of  54  diurnal activity i n  as a f a c t o r i n f l u e n c i n g the  sex r a t i o . a complete annual  turnover  a t some t i m e  i n population  occurs  period  the  f e m a l e , due t o t h e d r a i n i m p o s e d by t h e b e a r i n g  and t h e f o l l o w i n g s p r i n g , i t i s n o t u n l i k e l y t h a t  young, would,  i n a species  succumb e a r l i e r  than does  therefore,  the underlying  that  o f such high  the male.  and  metabolic  tied  i n closely with  I t appears h i g h l y  cause o r causes l e a d i n g  of  breeding  are involved  investigation.  breeding  activity.  Just  which  r e m a i n unknown and r e q u i r e  nursing  rate,  preponderance o f males a f t e r t h e young b e g i n  is  on t h e  between t h e end o f t h e b r e e d -  ing  observed  revealed  f e m a l e was c a u g h t .  Sorex i n the t o t a l  basis  due  a d v a n c e o r b o t h may b e a  by t r a p p i n g  taken only  c a n n o t be c o n s i d e r e d  death o f the adults  of  alter.  between sexes  sex r a t i o s .  result i n a smaller  were taken by day. the  seasonal  c h a n g e s i n d i e t o r s u f f e r some  Diurnal activity that  to trapping  i n f l u e n c i n g the observed  possible  number  does n o t  fewer females  at  appear.-  the effects of breeding,  factor  sex ratio  to the observed  and a f t e r t h e datum p o i n t  A change i n s u s c e p t i b i l i t y to  balaced  probable t o an to run aspects  further  70. The o b s e r v e d  distributions  Goose I s l a n d s i s d i f f i c u l t  o f Sorex populations upon t h e  to explain satisfactorily.  factors  contributing to the suitability  a given  s p e c i e s depend l a r g e l y upon a v a i l a b l e  humidity, is  cover  often unable  practically  and a v a r i e t y  o f such  this  s p e c i e s i tappears obvious  technique  food,  climate,  conditions which  i s known o f these  In analyzing the distributional to  o f an environment f o r  t o measure a c c u r a t e l y .  nothing  The  I n t h e case  man  o f Sorex  requirements. data  gathered  i n respect  that the refinements  of  i n t h e assessment o f Sorex range were inadequate. .  I t has been p o s t u l a t e d t h a t a micro-environment o f h i g h humidity  i s probably  of  animals.  these  an e s s e n t i a l  Based  on observations  the-only degree o f success when t h e y  were kept  I.McT.Cowan, P e r s . inspection,  dry.  of  The b e a c h d e b r i s o n t h i s  Yet"the  that, f i r s t ,  From  humidity  distribution,  these  gross  i t may  importance  that t h e apparent  by gross  i nthe micro-habitats; this  occurred  observations  i s of secondary  o r second,  a p p r a i s a l were inadequate.  In  occurred  b a s i s was  concentrations o f Sorex  t h e four h a b i t a t s observed  correct  individuals  and c o n i f e r o u s f o r e s t must a l l  i n meadow a n d i n b e a c h d e b r i s .  flected  specimens,  On t h e G o o s e I s l a n d s , f r o m  t h e meadow, m u s k e g  comparatively  of  of captive  i nmaintaining  Comm.).  as humid.  determining  f o rthe survival  i n t e r r a r i a under humid c o n d i t i o n s (Dr.  be c l a s s i f i e d  be assumed  requirement  i n  humidity  a n a l y s i s was n o t r e -  i m p l i e s t h a t t h e methods  I believe the latter  t o be t h e  assumption. considering available  food  as a f a c t o r ,  the insecti-  vorous nature of  these  animals  Certainly vore.  o f Sorex must be kept utilizing  observed  noticeably  life  appeared  throught  of the Insecti-  productive of a l l .  d e s p i t e an apparent food  abundance  and muskeg  of point  harbored  sampling,  The h i g h e s t  i n t h e meadows.  concentration  I t was-a.ssumed  l a c k o f i n s e c t s t h e r e must have  t o support  the populations observed.  sequently  the relative  different  h a b i t a t s cannot be used  abundance o f i n s e c t s apparent  distribution  Assuming  A varied  that food  as a factor  i n the  i nexplaining  o f Sorex.  supply  and  may b e c o n s i d e r e d .  meadow a p p e a r e d  greatly  and c o n d i t i o n s o f humidity  little  direct  no  competition  respects  f a c t o r may b e o f  nocturnal  species.  i n t o l e r a n c e I s e l i m i n a t e d as an i n f l u e n c i n g  On t h i s  caught Peromyscus  e x i s t e d f o rfood  remains  sun-  o f Sorex varied  on t h e b a s i s t h a t . Sorex were c o n s t a n t l y t a k e n  same t r a p s w h i c h  to  r e s p e c t beach d e b r i s , muskeg  In addition this  consequence t o such  Interspecific factor  In this  equal, yet the distribution  i n a l l three.  been  Con-  were' c o m p a r a b l e a n d a d e q u a t e i n a l l h a b i t a t s , e x p o s u r e light  by  t h e meadow h a b i t a t , t h o u g h  i n the course  shrews however, o c c u r r e d  observed  the habitats occupied  examination.  fewer i n s e c t s while  least  sufficient  the  a r e those  i n t h e beach d e b r i s ; f o r e s t  examined more m i n u t e l y  that  aspects  food.  Through n e c e s s i t y , t h e a p p r a i s a l o f t h e r e l a t i v e  S o r e x was a l s o one o f g r o s s  of  I have no r e c o r d  v e g e t a t i v e m a t e r i a l s as  themorphological  abundance o f i n s e c t  was  i n mind.  and M i c r o t u s .  while  i n the  Apparently  competition i n other  unknown.  basis o f gross  examination,  t h e cover  type o f  .72. t h e meadow r e p r e s e n t e d b y - l u s h s t a n d s observed factor  difference  t h a t c o u l d be c o n s i d e r e d as a  i n the observed  Islands.  I n view  micro-ecological differences  and  distribution  o f inadequate factors  of this  confidence.  s p e c i e s on t h e Goose  associated with gross  Further investigations  to the  observed  f o r t h e observed  c a n be p o s t u l a t e d here  behavior patterns o f these  contributing  knowledge p e r t a i n i n g  i n h a b i t a t however, no r e a s o n s  d i s t r i b u t i o n o f Sorex of  o f g r a s s was t h e o n l y  into  w i t h any degree the l i f e  history  diminutive animals are  indicated. Sorex have l e f t The  inhabiting those  evidence  areas  left  disappearance,  t h e p e r i p h e r a l h a b i t a t s must i n w i n t e r as d i d t h e rodent  by shrews i s minute  consequently  annual  although  may r e s u l t  t h e complete  on t h e O r i g i n a l  British  Columbia  of  cold  finding  annual  t h a t o f t h e o t h e r two  turnover i n population  investigator Pacific  seas  Occurrence  having  o f I n s u l a r Mammals i n  travelled  to reach  f o rhours  a small i s l e t ,  i t o c c u p i e d b y s m a l l mammals, b e g i n s  upon t h e manner i n w h i c h  those  animals  formidable  which  he has j u s t  modern  of  i nfundamental-differences.  Theories  Any  occupation i nthe  The s e a s o n a l a c t i v i t y  y o u n g may b e a s s u m e d t o p a r a l l e l  species,  species.  and s u b j e c t t o r a p i d  traces of their  w i n t e r months were o b l i t e r a t e d .  necessarily  expanses over  over  stretches  invariably,  upon  to speculate  have n e g o t i a t e d t h e travelled  i n a  vessel.  From these Two o f t h e s e  s p e c u l a t i o n s four main t h e o r i e s have  r e q u i r e s u b s t a n t i a t i o n b y a more c o m p l e t e  developed. geolo-  73. gical of  picture of the coast  the last  glacial  knowledge o f t i d a l forever  a s i t was d u r i n g >  period, another currents, while  i n the field  requiring  glaciated 2. ice  insular  bridges  ancestors  populations areas  t h a t may  of the present  out.  These  forms o f l i f e ,  4.  t h e i c e age i n  and s u r i v e d t o r e p o p u l a t e  the  —  populations  over  bearing  r a n ashore  p o s s i b l y on distant o f human  of  Indians  inhabiting  on  insular  groups,  may  o f mammals t o t h o s e  acres  carrying with  temporary  which the  migrated.  o f a n c i e n t and recent  slides  which  The t h e o r y  of the i c e left  t h e o r y p o s t u l a t e d by McCabe and  borne o f f on t h e t i d e s  lodged  rest  presented:  through  have been vegetated,  i n which evidence  pointed  lived  that the retreat  The " s l i d e "  (1945)  may  p o r t i o n s as t h e i c e withdrew.  The c o n c e p t  3.  detailed  of conjecture.  That r e s i d u a l  unglaciated  a more  the remaining  These four t h e o r i e s a r e , i n t h e order 1.  and a t t h e c l o s e  Cowan  land  slides are  o f v e g e t a t i o n were  them mammals a n d  when t h e r a f t s  other  eventually  islands.  transportation.  the coast  and moving  w e l l have  Large  populations  seasonally to  transported certain  groups where t h e y  have  fish  species  subsequently  become  established. The along the That  complexity  the British  reader's  and v a r i a t i o n  Columbia coast  of the islands may  a t t e n t i o n by a glance  be f o r c i b l y  a t a n y map  i n distributing  the animals  channels  brought to  of the area.  a n y o n e o r a l l o f t h e p o s t u l a t e d f a c t o r s may  instrumental  and  as t h e y  have appear  been to-day  ,74. is  h i g h l y probable.  from the  I n cases where i t i s p r a c t i c a l l y  geological evidence sea,arising  only  that  after  an i s l a n d  of residual population  In  cases however,  theory.  Recent  reveal  explained  this  isolated  s m a l l mammal  only  on t h i s  and i c e bridge  appears  islets  o f t h e Queen  slide  that  Charlotte  c a n be  The i n d i g e n o u s  caribou of  out the p l a u s i b i l i t y of  the  floating  as an agent o f d i s t r i b u t i o n .  ing  t h e g e o l o g i c a l h i s t o r y o f t h e Goose I s l a n d s  to be t h e most l o g i c a l  Bella  animals  present  explanation  The g r o u p h a s l o n g  Indians  real  been u t i l i z e d grounds;  may h a v e b e e n t r a n s p o r t e d  consider-  this  appears  one i n t h e case o f t h e u b i q u i t o u s however,  by the that the  alleged this  Peromyscus.  the reality  as an agent o f d i s p e r s a l decreases.  a  very  I n the  lessens. of the  Bears are  b y many t o h a v e a r r i v e d u p o n t h e Queen C h a r l o t t e s i n  manner, t r a n s p o r t e d  goats  inhabiting Pitt  there  from  Indian  loaded  certainly  W h e r e l a r g e r mammals a r e i n v o l v e d t h e p l a u s i b i l i t y aboriginal  of small  i n canoes,  i sa possibility,  case o f Sorex and M i c r o t u s ,  On  f o r the presence  a s a summer f i s h i n g  with household materials  logically  case i n p o i n t .  McCabe and Cowan (1945) p o i n t  Bella  are eliminated.  t o be t h e o n l y p l a u s i b l e  distributions  basis.  Graham I s l a n d i s a n o t h e r  mammals t h e r e .  below  i n v e s t i g a t i o n s by t h e U n i v e r s i t y o f B r i t i s h  Columbia on outer group  was c o m p l e t e l y  the disappearance o f the i c e , the  concepts other  certain  while  young.  The m o u n t a i n  I s l a n d a r e s a i d t o have been  the mainland  chieftain.  as pets  i n comparatively  recent  taken  times  b y some  T h e s e two a l l e g a t i o n s t o - d a y a r e l i t t l e  75. more t h a n  rumour, whether t h e i r  more d e f i n i t e As  rating  one views  status w i l l  t h e range  i n degrees  invasion nitude  or series  to.effect  isolated  separating It  manifest  races o f a  presented.  groups  a s t h e Goose I s l a n d s . islands  ultimately  isolation  that  sufficient  such mag-  such  the nature  of the  concept.  p o s t u l a t e d above a r e more o r group  of islands  F o r t h e main p a r t however, shores  unsurpassed  a  In the closer  be shown, a s o u r k n o w l e d g e  t o one i s l a n d ,  along these  presenting  as w e l l ,  discourages  some o f t h e f a c t o r s  another.  The p o s s i b i l i t y  p h e n o t y p i c a l e x p r e s s i o n seems r e m o t e i n s u c h  channels  will  applicable  lying  the insular  of invasions could attain  network o f the i n s i d e  that  of speciation  species (Peromyscus m a n i c u l a t u s ) , t h e q u e s t i o n o f  Invasion i s immediately  well  assume a  i s very doubtful.  by m o r p h o l o g i c a l c h a r a c t e r s t h r o u g h o u t given  ever  the insular  i s made u p o f w e l l  logically they  areto  complex  isolated  o p p o r t u n i t i e s o f study  and s p e c i a t i o n .  than  accumulates,  units  i n the field  of  76.  Summary a n d 1.  Conclusions  The Goose I s l a n d g r o u p  logical  unit  British  Columbia  2.  Eleven  typical  represents  o f many o u t e r  fringe  islands  major v e r t e b r a t e h a b i t a t s occur  boulder  beach, t i d a l  mud f l a t ,  discussed  i n the foregoing  longicaudus occur,—  4.  o f Castor  The s m a l l p o p u l a t i o n s  numbers  representing both  i s not  i s represented  by  Microtus  Two s p e c i e s o f b a t s and M y o t i s  three  also  yumanensis.  o f bats  o c c u r r i n g were  of the coniferous forest. species  are attributed  confined The  small  to the effect  wind.  5.  Peromyscus maniculatus  was t h e most  most abundant  species of t e r r e s t r i a l  three percent  of the total  Distribution  percent; variety  nesting sites,  this  of this  Sixtyspecies.  Beach d e b r i s ,  25.54;^percent;  a n d meadow, 1 0 . 2 9 p e r c e n t .  the h a b i t a t s appeared  d i s t r i b u t e d and  mammal p r e s e n t .  as f o l l o w s :  coniferous forest,  o f food,  evenly  c a t c h was c o m p r i s e d  by h a b i t a t appeared  46.79 p e r c e n t ;  »  coast  once i n h a b i t e d t h e i s l a n d s .  to the environs  6  The l a t t e r  Peromyscus maniculatus,  and Sorex obscurus.  chiefly  of  fauna  Lasionycteris noctivagans  A species  —  paper.  The t e r r e s t r i a l mammalian o f s m a l l mammals —  upon t h e i s l a n d s  sandy sea beach,  p e l a g i c and f r e s h water h a b i t a t .  species  along the  m u s k e g , meadow, r o c k y s e a  littoral,  3.  i s o l a t e d eco-,  coast.  Beach d e b r i s , c o n i f e r o u s f o r e s t , shore,  a well  muskeg, 17.38  The a v a i l a b i l i t y and  and t h e r e l a t i v e  t o be t h e m a j o r f a c t o r s  dryness  of  accounting f o r  distribution. Microtus  longicaudus  was r e s t r i c t e d ' t o a r e a s  i n which  77. grasses three 14  occurred.  terrestrial  percent  06.67 p e r c e n t ;  forms present,  habitat, types  cover  beach  factors  Of t h i s  leading  to this  the  only  8.  Sex r a t i o s  species  percent.  contributingto  distribution  apparent  factor  based  27.78 p e r c e n t  i n t h e meadow.  a r e obscure.  running  were  The  I n gross  i s density o f the grass  take o f taken  and M i c r o t u s  cover.  longicaudus. i n Sorex  factors analyses  o n snap t r a p p i n g were i n d i c a t e d  m a l e s p r e d o m i n a n t , was o b s e r v e d  ratio  of the total  i n c o n i f e r o u s f o r e s t , 11.11  a n d 50 p e r c e n t  Peromyscus maniculatus  ratio,  23 p e r c e n t  d e b r i s , 11.11 percent i n muskeg  9.  forest,  o f ground bases i nt h e  as m a j o r  represented  forms.  percent  and,  coniferous  as  distribution.  terrestrial  This  approximately  a n d meadow, 7 0  and t h e n a t u r e  are considered  abundant o f t h e  The c a t c h was d i s t r i b u t e d  muskeg, 10 p e r c e n t ;  Sorex obscurus  in  catch.  representing  d e b r i s , 13.33 percent;  Density o f grass  in  s p e c i e s was t h e l e a s t  of the total  follows:- Beach  this  This  a s 1:1 A 3:1  obscurus.  seems t o b e c o r r e l a t e d w i t h t h e a p p e a r a n c e o f  young and i s c o n s i d e r e d  o r other undetermined  due t o m o r t a l i t y  i n females  changes a s s o c i a t e d w i t h  Peripheral habitats bordering  breeding.  the sea,represented  by  b e a c h d e b r i s a n d m e a d o w , a r e p r e f e r r e d summer r a n g e f o r t h e terrestrial indicates of  Winter  that a reversal  season r e s u l t s  interior and  forms.  sign correlated with trapping of optimal  This  change  i n p o p u l a t i o n movements from p e r i p h e r a l t o  habitats, the latter  muskeg.  conditions with  data  represented  by c o n i f e r o u s  forest  s e a s o n a l movement i s p r e c e d e d . b y t h e a n n u a l  78. increment pressure.  o f young  peripheral  In the latter  the  activities  10.  Limpets  diet  of coastal  11.  Predation  existant  from  case^due  o f Sorex obscurus  and small  crabs form  habitats to lack  due t o  -population  of durable  sign,  a r e assumed. regular  i t e m s I n t h e summer  Peromyscus. as a f a c t o r  influencing  small  mammals was n o n  i n t h e summer m o n t h s o f 1 9 4 8 o n G o o s e  Island.  .7?; LITERATURE Aldous,  S.  E.  1944.  A  CITED  deer  brouse  M a m m a l o g y 25 Asdell,  S.  A.  1946.  survey method.  ( 2 ) : 130-136.  P a t t e r n s o f mammalian r e p r o d u c t i o n . C o m s t o c k P u b l . Co.,  Clarke,  S.  E.,  Journ..  Campbell,  J . A.  and  I t h a c a , New  Campbell,  An  ecological  and  in  southern Alberta.  York.  J . B.  1942.  grazing capacity Dom.  Can.  study  Tech.  Bull.  44. Dice,  L.  R.  1938.  Some c e n s u s  m e t h o d s f o r mammals.  Wldlf;.°Mgmt. 2 Guiguet,  C.  J . 1946.  H o w a r d , I V E.  Unpublished  1949.  Dispersal, longevity prairie  Journ.  ( 4 ) : 119-130. field  records.  amount o f  i n a local  deermice  on  inbreeding, population of  the  George  Reserve,  s o u t h e r n M i c h i g a n . M i s c . P u b l . Mus. Univ. Mich. M c C a b e , T.  T.  M c C a b e , T.  and  T.  C o w a n , I . McT.  Trans.  Can.  Beaver  on  islands. Snedecor,  G.  W.  1938.  L.  F.  1946.  Peromyscus  the problem  of  the n o r t h e r n B r i t i s h  Can.Field-Nat.  Ames,  insularity.  62  Columbia  ( 2 ) : 72-74.  Collegiate  Press  Iowa.  Experimental analysis measuring  maniculatus  Inst.  S t a t i s t i c a l methods.  Inc., Stickle,  1945. and  1948.  Zool.  43.  macrorhlhua Roy.  and  o f methods f o r  s m a l l mammal p o p u l a t i o n s . J o u r n .  W l d l f . M g m t . 10  ( 2 ) : 150-159.  80. T o w n s e n d , M.T.  1955.  S t u d i e s o n some o f t h e s m a l l m a m m a l s o f  central  New Y o r k .  Annals.  4(1).  Roosevelt  Wildlife  

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