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Conifer seed predation by the deer mouse : a problem in reforestation Sullivan, Thomas Priestlay 1978

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CONIFER  SEED PREDATION A PROBLEM IN  BY THE DEER MOUSE:  REFORESTATION by  T.HOHAS PRIESTLAY SULLIVAN B- Sc.  (Hons.) , U n i v e r s i t y  H.Sc., U n i v e r s i t y THESIS .SUBMITTED  o f B.C.,  o f B.C.,  1973  1976  IN PARTIAL FULFILLMENT 0  THE REQUIREMENTS FOR THE DEGHEE OF DOCTOR -OF PHILOSOPHY in THE FACULTY OF GRADUATE (Departmeat  We a c c e p t t h i s t h e s i s  STUDIES  o f Zoology)  as conforming to t h e  reguired standard  THE UNIVERSITY OF BRITISH COLUMBIA NOVEMBER, 1978  ©  Thomas P r i e s t l a y S u l l i v a n , 1978  In p r e s e n t i n g t h i s t h e s i s i n p a r t i a l f u l f i l m e n t o f the r e q u i r e m e n t s  for  an advanced degree a t the U n i v e r s i t y of B r i t i s h C o l u m b i a , I agree t h a t the L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r r e f e r e n c e and s t u d y . I f u r t h e r agree t h a t p e r m i s s i o n f o r e x t e n s i v e c o p y i n g of t h i s  thesis  f o r s c h o l a r l y purposes may be g r a n t e d by the Head of my Department o r by h i s r e p r e s e n t a t i v e s .  I t i s understood t h a t c o p y i n g or  publication  of t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l not be a l l o w e d w i t h o u t my written permission.  Department n f  Zoology  The U n i v e r s i t y of B r i t i s h Columbia 2075 Wesbrook P l a c e V a n c o u v e r , Canada V6T 1W5  Qg-j-g  January 1 8 ,  1979.  Abstract fieforestation of  seed  has  Destruction resulted  of c u t o v e r f o r e s t long  been  o f t h e seed  in  from  and  include  seed-eating  repellents  applied  has  successful.  been  involving describe conifer  directly  biological  birds.  t o seeds.  control,  The  of  have  mice and  related  forested  regions.  to  test  habitats  the  small  widely-held  forested  in  forest  habitats. and  practice  from  population  was m o n i t o r e d  15.8  (1976),  (1975),  on  clearcut  chapter i n t h i s  o f mice  to  from  number o f a n i m a l s  areas  April  clearcut  Maple  Peromyscus  April  per ha i n t h e f o r e s t clearcut  on t h e c l e a r c u t  British clearcut  1978.  was: 19.6 areas  on  one  The  (1975),  was:  The s l i g h t l y  i n 1975, a n d  than  live-trapped  Another  to  29.9 and 20.2 ( 1 9 7 7 ) .  in  (logged)  Bidge,  1978.  1977  than  t h e s i s was d e s i g n e d  that  at  April  22.3 (1977) and on t h e  16.6 (1976),  Most  t h e r e a r e h i g h e r d e n s i t i e s o f deer  habitats  1975  reducing  documented.  Deer mouse p o p u l a t i o n s were  Columbia,  density  May  for  will  on p o p u l a t i o n s o f d e e r  well  hypothesis  clearcut  techniques  mice.  mammals  The f i r s t  technique  support higher d e n s i t y p o p u l a t i o n s o f  do  average  that  control  and c o n s e q u e n t l y , t h i s t h e s i s  forestry  concluded  seed  and c h e m i c a l  None o f t h e s e  mice and o t h e r s m a l l mammals have been studies  tree  r e s e a r c h h a s been done on methods  p r e d a t i o n i n deer  effects  baits,  has  projects-  Conventional  the development of a b i o l o g i c a l seed  birds  f o r protecting  devices, poison  Little  and  America.  o f these r e f o r e s t a t i o n  been d e v e l o p e d  mechanical  application  i n North  by s m a l l mammals  a general f a i l u r e  rodents  methods  a goal of foresters  supply  Numerous t e c h n i q u e s have  l a n d by d i r e c t  23.3  higher of  the  clearcut late  a r e a s i n 1977,  summer and  clearcut to  fall  of each  areas declined  that  in  clearcut  reflected  the forest-  in  consistently  h e a v i e r than  during  male  were  removal  second  able  cleared  fir  seed  fall  #  survival  o f 99  moved o n t o  within  experiment  a  3-day  i n the  habitat  destroyed  92.6%  intensive  into  the c l e a r c u t  c o n t r o l and  o f seed  removal  owing t o t h e r a p i d the seed The  to t e s t  the h y p o t h e s i s  area  would  Areas  a r e a s has reinvasion  of  and  area.  a  immigrated These 5-day  by m i c e and  Douglas  consequent  the  seed  of  was  removal into  the  animals  period.  futility  of  Animals  movements o f d e e r the  were  During  during  regions.  ha  in  Colonization  95% o f t h e c o n i f e r  o f 48 mice  shown  o f 1.1  were m o n i t o r e d .  seed w i t h i n a  survival  result  the s u r v i v a l  a depopulated  that  This  mice  on  baiting  destruction  supply.  third  biological  c o n i f e r seed  after logging.  seed.  surrounding  populations  year  Similarly,  total  little  male  m i c e and  period.  was  Juvenile  t h e a r e a , and  of the c o n i f e r  study  there  r e l a t e d s m a l l mammals.  spring, a from  but  the  the c l e a r c u t .  given  mice c o l o n i z e d  comparable  sere  conifer  a r e a s by d e e r  on  animals  designed a  mice  Forest  d i s p e r s e d over the c l e a r c u t  a total  vacant  of  o f d e e r mice and  continually  a  enter  c h a p t e r was  these depopulated  of  to  of  the  m i c e were b r e e d i n g on  reproduction.  o f a l l d e e r mice from  satisfactory  density  i n the f o r e s t ,  t h o s e on  recruitment i n  winter t o a l e v e l  the b r e e d i n g season i n the f i r s t  The  lost  The  More f e m a l e  i n a l l y e a r s than  mice  year-  d u r i n g each  difference  deer  a burst of  c h a p t e r d i s c u s s e s t h e use o f  alternative  control  successfully  t e c h n i q u e which has  p r e d a t i o n by d e e r  mice.,  The  upper  limits  foods  as  reduced to  the  iv  number  of  mice  determined The  and  o v e r a wide r a n g e  number o f s e e d s  Experiments density  number  with  in  of  7  Douglas  the best r e s u l t s :  control  in  the e a r l y  results  Douglas  obtained  experiments year  spring  and  with with  were  in  the f a l l  alternative lower  done  f i r seed.  1  at  seeds/ha. this  These  of conifer  mixtures  seed  after  5%  These  results  with  similarly  densities  of  other  were o b t a i n e d favourable Seeding  times  sunflower  2  survival  (November t o D e c e m b e r ) .  foods d u r i n g  seed  f i r and 5  Douglas  H weeks compared w i t h  to April)  mouse were  860,000  f i r seed.  f i r by i t s e l f . (March  to  70% s u r v i v a l  weeks and 50% s u r v i v a l a f t e r of  foods  per  of Couglas  at about  sunflower  1  taken  of d e n s i t i e s  alternative  ratios  seeds  taken s t a b i l i z e d  sunflower to 2 oats t o produced  of  of  the  s e e d s were not  successful. The this  fourth  and f i f t h  biological  seeding.  of  mice) and b i r d s  presumed  in  conifer  seed-eating (several  southwestern  mixture  area seed  of  This  number  to  be  0.10  direct low  (chipmunks  and  deer  late  fits seed  kg D o u g l a s by  by  of  to  aerially  of seeds  and 7 kg o a t s p e r h a .  application  respect  the  period  for conifer  seed  with  mammals  species) i s i n  i s as f o l l o w s :  (equivalent  sunflower seed  small  D.C.  the  to r e f o r e s t a t i o n  f o r seeding  most f a v o u r a b l e t i m e  recommended clearcut  technique  The v e r y b e s t t i m e  populations  spring  control  chapters discuss  winter-early  i n well  w i t h the  germination. seeded  over  The a  f i r seed o r o t h e r  weight)  to  56  kg  V  TABLE 07 CONTENTS  Abstract  .................................................  TABLE OF CONTENTS  i  .......  iv  L I S T OF FIGURES ......................... ^ .. ^ ........ L I S T OF TABLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  v i i . . . . . . . .  X  ACKNOWLEDGEMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . x i i GENERAL  INTRODUCTION  DESCRIPTION OF STUDY CHAPTER  1.  .. AREAS  ...  4  DEMOGRAPHY OF POPULATIONS OF DEES MICE IN  FOREST AND CLEARCUT INTRODUCTION  (LOGGED)  HABITATS.  ..  ...  ...........................................  MATERIALS AND METHODS  ........  RESULTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Trappability  .........................................  P o p u l a t i o n d e n s i t y and r e c r u i t m e n t Reproduction  11 11  14 16  ,.....,..........,.....y...............  DISCUSSION  -  FIGUBES . . . . . . . . . .  ...............................  TABLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . BEPOPULATION OF VACANT  20 23 23 31 49  CLEABCUT HAEITAT  CONIFEB SEED PREDATION BY THE DEEB MOUSE-  IN T80DUCTION  RESULTS  9  .........................................  Sex r a t i o s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  MATERIALS  7  12  Growth . . . . . .  AND  7  ...................  Mortality  CHAPTER 2.  1  AND METHODS ................. ' m . . . . . . ,  57 ..... ......  57 59 61  Trappa.bil.ity .........................................  61  Experimental  62  poison  baiting  ..........................  DISCUSSION . . . .  66  FIGUBES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TABLES CHAPTER  ..........  73  .... 3.  87  THE USE OF ALTERNATIVE FOODS TO REDUCE  CONIFER SEED PBEDATION  BY DEEB MICE  90  INTRODUCTION  90  MATERIALS  92  AUD METHODS . . . . . . . . . . . . . . . . . .  D o u g l a s f i r seed  p o p u l a t i o n s .........................  93  Predation ............................................  94  Badioactively-tagged  ............................  95  I n v e r t e b r a t e p o p u l a t i o n s .............................  96  Laboratory  97  seed  s t u d i e s ...................................  alternative  food  seed  t r i a l s .........................  RESULTS . . . . . . . . . . . . . . . . . . . . Trappability  97  -  99  . . . . . . . . . . . . ..... . . . . . . . . . . . . . . . . . . . . . . . .  Experimental seeding  with  100  Douglas f i r seed ...........  101  Seed c o n s u m p t i o n . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  101  Badioactively-tagged  ........................  102  ........................................  103  Invertebrates  Responses of deer Experimental alternative  mice t o D o u g l a s f i r s e e d s . . . . . . . . . .  seeding foods  DISCUSSION . . . .  SEASONAL  Douglas  .....................  ............  105 109  . 116  ......  ABUNDANCES OF CONIFER  103  f i r s e e d and  ----  TABLES . . . . . . . . . . . . . 4.  with  ....................................  FIGUBES ..........  CHAPTER  seed  , 140 SEED  yii  PREDATORS.  .......................  INTRODUCTION MATERIALS Chipmunk  .....  AND  151  .............................  METHODS  .  ----  152  p o p u l a t i o n s .................................  Copulations o f seed-eating RESULTS . . . . . . .  birds -  Chipmunk p o p u l a t i o n s  .....................  ---  b i r d s .....................  DISCUSSION  ....  CONIFER  153 154  157 REFORESTATION  SEED AND  INTRODUCTION  BY DIRECT SEEDING  ALTERNATIVE FOODS.  »ITH  .....................  ..............  RESULTS . . . . . . . Direct  153  . 154  FIGURES CHAPTER 5.  152  153  .................................  Populations o f seed-eating  151  seeding  ......... with  161 ..........................  Douglas  f i r  alternative  foods.  Application  i n reforestation projects  Economic a s p e c t s  161  seed  162  and  ..................................  162  . . . . . . . . . . . . . . . . . 163  .....................................  164  DISCOSSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  164  FIGURES  169  LITERATURE CITED  ,  173  viii  L I S T OF FIGOHES  Figure  1.1.  Location  Figure  1-2-  Aerial  of the four study areas.  1.3.  Aerial  areas.  1.4.  Figure  1.5.  control Figure  1.6.  control Figure  1.7.  d e n s i t y on f o r e s t  grids.  Population  1.8.  Growth  Figure  1.9.  Median body  ..............................  r a t e s f o r deer mice d u r i n g  mice d u r i n g  Figure  2.1a.  Hap o f s t u d y  Figure  2.1b.  Predicted the  Figure  2.2.  2.3.  area  1975-77.  .  46  periods.  ...........  48  f o r removal experiments.  74  onto  ..........................  O r i g i n o f mice c o l o n i z i n g r e m o v a l g r i d e x p e r i m e n t A-  44  maturity f o r  r e s p o n s e o f mice moving  removal area.  during Figure  summer  42  during  ............................  weight a t s e x u a l  40  Lake  w e i g h t s f o r d e e r mice  Figure  38  and Burn  d e n s i t y on t h e Loon  summer p e r i o d s .  deer  ................  .............................  grid.  Mean body  36  with t r a p s t a t i o n s  seed s a m p l i n g g u a d r a t s .  Population  34  Lake  ................................  Live-trap grid and  ........................  photograph o f t h e Loon  study area. Figure  32  p h o t o g r a p h o f t h e B u r n , S l a s h , and  f o r e s t study Figure  ..........  76  J  .......................  78  O r i g i n o f mice c o l o n i z i n g r e m o v a l g r i d J during  e x p e r i m e n t B.  .......................  Figure  2.4.  Population  Figure  2.5-  O r i g i n o f mice c o l o n i z i n g r e m o v a l g r i d J during  d e n s i t y on g r i d s H, I , and J .  e x p e r i m e n t C.  ...  .......................  80 82  84  ix  Figure  2.6.  Origin  o f mice c o l o n i z i n g  d u r i n g e x p e r i m e n t D. Figure  3.1.  Figure  Figure  3.3-  3.4.  3.5,  densities  of Douglas f i r seed.  Responses  o f numbers o f new  densities  of Douglas f i r seed.  Number o f s e e d s t a k e n  d i f f e r e n t seed d e n s i t i e s  seed Figure  Figure  3.7.  3.8.  (7:1 r a t i o )  3.10.  3.12.  4.1.  i n the f o r e s t .  oats  Survival  Survival  Survival  Survival  Survival  i n laboratory.  . 125  i n August  1976.  127  i n August  1976.  129  o f D o u g l a s f i r , s u n f l o w e r , and o a t s i n August  1976.  ......  .... 131  o f D o u g l a s f i r and s u n f l o w e r s e e d i n November  1976.  ..............  133  o f D o u g l a s f i r and s u n f l o w e r on t h e c l e a r c u t  o f Douglas  ratio)  i n spring  1977.  135  1977-  -. 137  f i r , s u n f l o w e r , and  i n November  Numbers o f chipmunks during  i n spring  f i r and s u n f l o w e r  i n the f o r e s t  o f Douglas  (5:2:1  traplines  . 123  p e r day  (7:1 r a t i o )  oats Figure  p e r day  and  (7:1 r a t i o ) Figure  --...-.-.,..,121  o f a mixture o f Douglas f i r seed  (7:1 r a t i o ) F i g u r e 3.11.  to d i f f e r e n t  Survival  (7:1 r a t i o ) Figure  mice  o f D o u g l a s f i r seed and s u n f l o w e r  (3:3:2 r a t i o ) F i g u r e 3.9.  .............119  o f s e e d s t a k e n p e r mouse  Survival  during  to different  p e r mouse  d i f f e r e n t seed densities  Number  86  ....................117  o f numbers o f mice  at F i g u r e 3.6.  i n 1975.  Responses  at Figure  .......................  C u m u l a t i v e number o f s e e d s t a k e n seeding t r i a l s  F i g u r e 3-2-  removal g r i d J  1S77.  on t h e Burn  1976-77.  .......  139  and S l a s h  ..................  158  X  F i g u r e 4.2.  Numbers o f t h e s i x most common bird  Figure  5.1.  5.2.  ..................  160  Success o f d i f f e r e n t Douglas f i r to sunflower (and  Figure  s p e c i e s on t h e B u r n .  seed-eating  oats)  ratios.  .........................  Procedure f o r s u c c e s s f u l conifer  reforestation  s e e d and a l t e r n a t i v e  foods.  170  with  ........  172  xi  L I S T OF TABLES  Table  1-1.  Trappability three study  estimates areas.  f o r deer  mice  on t h e  ..........................  Table  1.2.  P r o p o r t i o n o f mice i n b r e e d i n g c o n d i t i o n .  Table  1.3.  Minimum s u r v i v a l study  areas.  rates  1.4.  Indices of early  Table  1.5.  Number  juvenile  of successful  survival-  pregnancies  1.6.  Sex r a t i o s i n t h e t h r e e  Table  1.7.  C o m p a r i s o n o f summer and f a l l and c l e a r c u t  1.8.  Summary  Table  2.1.  Trappability  estimates  experimental  areas.,  2.2.  of annual v a r i a t i o n  Comparison o f seed removal g r i d s .  Table  Table  2.3.  3.1.  Table  3.2.  estimates  Mean  3.3.  Number o f s e e d whole  Appendix  3.1.  on c o n t r o l  and e a t e n  55  ... 56  87  88  and  .........................  89  f o r m i c e on t h e grids.  number o f s e e d s p e r stomach seed  54  on c o n t r o l and  and s i x e x p e r i m e n t a l  different Table  ...............  ..............................  Trappability  53  f o r mice on c o n t r o l and  survival  grids.  52  densities i n  i n demography.  Numbers o f v o l e s and s h r e u s  control  ........  .........................  experimental  51  juvenile  populations.  habitats.  Table  Table  and  .........  ...................................  Table  forest  50  f o r mice on t h e t h r e e  ................................  Table  recr uits.  ...  49  densities.  .........  140  a t two  ...................  141  c a c h e s and p r o p o r t i o n o f seeds.,  The means, s t a n d a r d  confidence l i m i t s  ...................... errors,  f o r seed  142  a n d 95%  trials.  ..........  143  Appendix  3.2-  Summary  seeds  taken  of field  data  f o r number o f  per mouse p e r day-  ..............  150  xiii  ACKNOWLEDGEMENTS I  thank  Charles  encouragement d u r i n g helpful his  comments  this  on  throughout  Kachuk f o r a s s i s t a n c e help John  with  the field  Fryxell,  Lance  study  Research the  f o r h i s guidance  and  Dennis  Forest  study,  support  was p r o v i d e d  awarded  field  t o C.J.  am m o s t g r a t e f u l .  H a l t e r s and  f o r their  help  Walter Kaiser  of the seeds.  Jr.,  ¥ a t t s , and B i g W h i t e .  work and s y n t h e s i s o f t h i s by t h e B.C.  Krebs,  and  and K e n t Humphrey and B i l l  to Dru S u l l i v a n f o r h e r c o n t i n u a l i n s p i r a t i o n the  and  for his  work, I thank JBudy B o o n s t r a , C h r i s  Eric  during  Chitty  I a l s o thank J .  i n r a d i o a c t i v e tagging  D a r y l Jahnke,  Nordstrom,  Krebs  the thesis.  s t a f f a t t h e U.B.C.  cooperation  J.  Forest  and by a U.B.C.  Dick  For  Fleming,  Lancaster,  S p e c i a l t h a n k s go and  encouragement  study.  Service,  Financial  N.H.C.  Fellowship  funds  f o r which I  1  GENEBAL For used  almost h a l f  direct  IMTBODDCTIOH  a century  seeding  f o r e s t e r s i n North  a s a method o f r e g e n e r a t i n g  lands.  D e s t r u c t i o n o f t h e seed  birds  has  had  reforestation  adverse  (1973)  have  subject.  The d e e r mouse  supply  effects  projects.  Badvanyi  Black  on  predator  forest  mammals  success  Badwan  have  of  (Black  effects  1969; B a d v a n y i  of  logging  reviews  and this  i s  considered  i n the P a c i f i c  Northwest.  by  their  1S73; Pank  activity  birds  consumption  of  1574).  and f o r e s t r y  p r a c t i c e on  o f d e e r m i c e and o t h e r  s m a l l mammals have been  documented  (Hooven  Gashwiler  1973;  these  on  populations  1969,  and  (1970),  m i c r o t i n e s , and s e v e r a l s p e c i e s o f s e e d - e a t i n g  seeds  The  the  maniculatus)  have a l s o c o n t r i b u t e d t o t h e p r o b l e m conifer  cutover  small  comprehensive  (Peromyscus seed  by  (1969),  provided  t o b e t h e most i m p o r t a n t Chipmunks,  America  well  1970; and B a d v a n y i  1973).  I n g e n e r a l , most s t n d i e s h a v e c o n c l u d e d  that  there  higher  densities  small  mammals on  clearcut  areas  of  than  predation  conventional  Conventional following (196S,  by s m a l l  and  related  which  secondly,  there  methods  discussion  to  mammals and b i r d s .  methods  control  1970).  and  two b a s i c a p p r o a c h e s  control  chemicals,  mice  i n forested regions.  T h e r e have been seed  deer  are  about  have  have i s  reducing Firstly, mainly  biological  predominated,  them i s b a s e d on r e v i e w s  C o n t r o l used i n t h e c o n t e x t  of this  conifer there are involved control. and  the  by Badwan  thesis  means  t o c o n t r o l damage. Since  the  early  N o r t h w e s t have t r i e d  1900*s,  forest  managers i n t h e P a c i f i c  numerous methods f o r p r o t e c t i n g  coniferous  2  s e e d s f r o m r o d e n t s and poison  baits,  seeds.  and  not  and  (Gashwiler  1969;  baits  as  or  species,  and  unknown  (see  application in  According  to  taken  research  Badwan  review  (toxicants  seed  towards  concept pest  has  an  population  diseases. generally  of  defined  and  be  use  to  replace In  the  biological type  of  as  on  is  direct  has  often  1969,  1S70).  priorities  chemicals of  persistent less  which w i l l  to  control. pesticides persistent methods  provide  long-  problem. control den  with Bosch  respect (1971).  average d e n s i t y  parasites,  control of  rapid  the  meantime, p e r h a p s  van  action  is  non-target  in  them w i t h  developed  short  either  seeds  methods  of  reduce the  a  very  environment  change  attempt t o  as  ineffective  for  (Badwan  by  However,  such  addition,  reliance  biological  the  projects  Poisons,  In  discussed  by  too  population  i n the  to  been  hazardous to  repellents  this reforestation  been  involves  1975).  seeds, are  reduce the  b i o l o g i c a l c o n t r o l can  concept  field  rodent  non-chemical  of  insects  initial  exclusive  repellents)  have  possible  germination  l e s s hazardous chemicals.  A broad  only  Hooven  and  to  directly  considered  E v a n s 1974).  from  trend  to  now  (1974), a s u b s t a n t i a l  place,  solutions  screens  these chemicals  and  term  applied  devices,  from s u r r o u n d i n g a r e a s i s o f t e n  on  toxicants  Evans  and  the  by  reduced  a  as  is  1969;  fate of  directed  is  of  reinvasion  the  such  rodents  toxicants  of  resulted  There  of  Elimination  incomplete  has  devices  repellents  Poison b a i t s are  control  periods.  and  mechanical  p r a c t i c a l for large-scale  reforestation.  because  These i n c l u d e  toxicants  Mechanical  expensive as  and  birds.  can  control  to This  of  a  predators,  or  also  i n which  be  more  the  damage  3  caused  by  agent  or  (1967),  the pest i s reduced process. who  includes  of  the  as  refer This  to  i n reduced  use  grain  and  of p r e f e r r e d  have  often  Browsing  around  minimized  of c o n i f e r  availability (Campbell  of  alternative  foods,  Evans  1975) . The  conifer  with  foods.  respect  d e n s i t i e s o f Douglas number  of  determined, seeds  could  mice then  a  and  to  to  F l o c k s of  dark-  reduced  food 1962).  by  the  s p e c i e s of browse  date,  in  providing  with deer browsing 1967;  and  technique  to  discussed  upper  (Hoy  Campbell  on  in  mice t o limits  and  counter  been based  responses o f deer  seeds  1860).  (Fitzwater  the  I f the  (Hagar  as a b u f f e r  be  mouse has  t h e use o f a l t e r n a t i v e  result  foods.  1967).  technique i s  of  also  away  The  number  may  waterfowl  may  biological  f i r seeds.  population  luring  cutover  Dasmann e t a l .  a  i n lowered  or a l t e r n a t i v e  preferred  p r e d a t i o n i n the deer  use o f a l t e r n a t i v e thesis  of  habitat  f r o m f i r s e e d by s u p p l y i n g  have been c o n c e r n e d  development seed  and  Howard  intentional  pest  meadow v o l e s  studies,  1966;  any  results  of o r c h a r d t r e e s  damage from  fiost  Barcn e t a l .  (Howard  p l a c e on  alternative  1960;  in  s e e d l i n g s by d e e r  1974).  which  (buffer)  diverted  the base  biological  biological control  shown some s u c c e s s  a r t i f i c i a l f o o d a t j u s t one Prunings p i l e d  control  assume t h e  in size,  j u n c o s have been e a s i l y  a  f o o d and c o v e r , o r  I f we  vegetable crops  by  been d i s c u s s e d by  p e s t ' s environment  be r e d u c e d  p r o c e s s has  from eyed  the  has  biological  numbers o f t h e p e s t s p e c i e s . d o e s not have t o  eliminated  T h i s approach  modification resulting alteration  or  the this  varying for  the  e a t e n p e r mouse c a n foods with  i n r e d u c e d p r e d a t i o n on  Douglas  the c o n i f e r  be  f i r  seeds.  4  P r e s u m a b l y , t h e mice d e v e l o p search image" t o e x p l o i t Howard e t a l . evidence  introducing  mice  and  food  with  source  Howard and  find  alternative  densities,  their  termed an  Howard and  Harsh  of  varying  increased  Cole  (1967), provided  Therefore,  by  palatabilities,  the p r e d a t o r s may  resulting  "olfactory  (1970) have  f o o d by s m e l l .  foods  distributions, a  might be  a food source.  ( 1 9 6 8 ) , and  that  what  switch to a  survival  of  new  conifer  seeds. T h i s study 1)  Test  the  was  designed  widely-held  habitats  support  higher  forested  habitats.  toz hypothesis  that  clearcut  d e n s i t y p o p u l a t i o n s of  2) T e s t t h e h y p o t h e s i s t h a t r e m o v a l  o f a l l deer  in  satisfactory  seed.  3)  Determine  conifer better  seed  Determine  and  how  this  Recommend  should Each  the  be of  of c o n i f e r  responses  densities  alternative  4)  5)  survival  and  of  the  deer  effects  Peromyscus  mice w i l l  these  result  of  of  or  providing  more  foods.  relates  to the  procedure  applied  than  m i c e t o a wide r a n g e  t h e s e a s o n a l abundances o f c o n i f e r  the  (logged)  best time by  which  in reforestation five  topics  for direct this  seed  predators  seeding.  biological  technique  projects.  i s presented  as a c h a p t e r  in  this  thesis.  DESCRIPTION OF  This Columbia Field  project  was  Research  installations  located  Forest  STUDY AREAS  in  the  University  a t Maple Ridge,  ( g r i d s and  lines)  B. C.  were l o c a t e d  of  British  (Figure in forest  1.1). and  5 clearcut the  habitats  southeast  corner  second-growth regeneration forest was  timber  the  red  by  1930  western  cedar  a  and  hemlock  (Thuja  menziesii):  The located  burn  i n two a r e a s  in  followed  was b u r n t  (Tsuga  (Eurn  the  and  Slash  southern  by  slash  burning  but p a t c h y  o r dead  with  slash  (Epilpbium  the north  but n o t b u r n t . composition  Of t h e s e  southwest  and  G r i d s A, on  to  and  logged  and  Grid  west  s i x g r i d s , G was  aspect,  and  Another study  area  i n the f a l l The s l a s h The  of  a l l others  20  were  grid  J.  i n the f a l l and  a  of  similar  T h e r e was a g r e a t e r  black  a  several  Q was l o c a t e d i n  raspberry  (Rubus s p e c t a b i l i s ) on  main  (Pteridium  and  sides  slash  was  Research  1974.  an g u s t i f o l i u T o ) ,  rubra),  salmonberry  the  growth o f b r a c k e n  that of the burn.  (Alnus  areas)  in others.  C o v e r i n c l u d e d dead  abundance o f r e d a l d e r  area.  of  i n August  i n some a r e a s  surrounding  leucodermis),  forest  and a l l were  K and L were on a s i m i l a r a r e a a l s o l o g g e d  species  a  Douglas f i r  study  part  abundant s u c c e s s i o n a l h e r b s .  1973  This  seme  i n t h i s area  other  the f o r e s t  in  heterophylla)  with  f i r e weed  less  Natural  resulted  o f my s t u d y .  aguilinum) ,  Grids  and  G r i d s G, H, I , and J were on an a r e a  was u n i f o r m  cover  1925.  of  terrain. habitat  1973  consisted  in  1932  habitat, in  g r o u n d v e g e t a t i o n was s p a r s e .  clearcut  Forest. of  flat  Forest,  fire  plicata)  C , B, E, F, and P were s i t u a t e d  relatively  The f o r e s t  Research  following  began between  dominated  (Pseudptsuga #  of  43 t o 45 y e a r s o l d a t t h e t i m e  western  B  ( F i g u r e s 1.2 and 1 . 3 ) .  degree on  (Rubus  on the s l a s h slope  with  relatively  flat  landscape. was added i n 1977 on a c u t o v e r a r e a  east  6 of L c c n Lake area,  (Figure  w h i c h was  was  very  flat  terrain.  1.3).  logged  Grids  i n the s p r i n g  s p a r s e amid t h e s l a s h .  Traplines f o r monitoring along  the  H and H were l o c a t e d  boundary  Burn and S l a s h  study  (Figure  this  Ground  vegetation  B o t h g r i d s were on  relatively  chipmunk  of the f o r e s t areas  o f 1976.  on  populations  were  and c l e a r c u t h a b i t a t s 1.2).  located a t the  7 CHAPTER 1  DEMOGRAPHY OF POPULATIONS OF DEEB  IN  FOBIST AND CLEABCUT  MICE  (LOGGED) HAEITATS  INTRODUCTION The the  effects  forest  on p o p u l a t i o n s o f s m a l l mammals by  cover  during the l a s t  have  been  30 y e a r s .  been  w e l l documented  Regeneration  lands  has  adversely  affected  supply  by s m a l l mammals and b i r d s .  o f these  removal  of  i n North  America  cutover  forest  by d e s t r u c t i o n o f t h e s e e d  The d e e r  mouse  (Peromvscus  maniculatus),  i n p a r t i c u l a r , h a s r e c e i v e d much a t t e n t i o n a s t h e  most i m p o r t a n t  seed  Consequently,  predator,  at least  s t u d i e s concluded areas  1950a; T e v i s Gashwiler  that there  compared  a  review  of seed-eating  removal o f t h e o v e r s t o r y animals  varies,  with  adjacent  Ahlgren  1959, 1970; B a d v a n y i to  logging.  Most  1966;  habitat  Hooven  t y B u n n e l l and Eastman  forest.  should  {Orr-Ewing  1969,  1973; 1S76).  (1976), the  be h i g h e s t s h o r t l y  The  relying  these  mice on  1973; and Hooven and B l a c k  animals  those  forest  mouse  of  i s a g r e a t e r number o f d e e r  with  1956a, 1956b;  According diversity  Northwest.  many s t u d i e s have d e a l t w i t h c h a n g e s i n d e e r  p o p u l a t i o n s and v e g e t a t i o n f o l l o w i n g  logged  i n the P a c i f i c  abundance  primarily  of  after  specific  on c o n i f e r  seed  8 increasing  i n abundance  preferring  other  with  seed  s o u r c e s from  more abundant e a r l i e r . exploits  annual  prefers  the  regrowing  to a  (1968)  populations  of  (1974) and  Sadleir  that  and in  deer  density mice.  Few  becoming  s e e d s a s w e l l as c o n i f e r  seeds,  stages  of  Sadleir  between  a  logged  area  from  their  year,  as  changes  in  over  be  numbers the  may  two  higher  in  be  sampled  deer  mouse  For  and  times  i s inadequate  habitat  w i n t e r t o a l e v e l comparable  mature  both s e a s o n a l  reflected  habitats. one  3-year  the  o n l y 2 or 3  c a s e w i t h most s t u d i e s ,  between may  Sampling  Sadleir  a r e a s were s i m i l a r i n  years to determine  v a r i a t i o n s i n demography.  very  clearcut  intensive  reproduction to those i n  through s e v e r a l  the  and  P e t t i c r e w and  o t h e r s t u d i e s have i n t e n s i v e l y  was  (1974) f o u n d  forest  In a d d i t i o n ,  annual  decline  those  which  (1974) c o n c l u d e d  forest.  recruitment  shrubs,  the deer  p o p u l a t i o n s on r e c e n t l y - l o g g e d  differences  and  mouse,  P e t t i c r e w and  r e c r u i t m e n t , and  temporary  age  h e r b s and  opinion,  successional  survival,  populations  stand  forest.  difference  study  In t h e i r perennial  earlier  Harris little  or  advancing  as  a  since  distinct  example,  fall  density  will  but to that  of the other  habitat. P o p u l a t i o n s of deer spring and  breeding  sinter  and  densities  (Sadleir  Sadleir  mice  1965;  1974;  Arnott  mice)  for  (1973),  seeding in  his  seasonally  and h i g h d e n s i t i e s  Healey  1967;  Fairbairn  T h e r e f o r e , the b e s t time deer  fluctuate  1977;  (with r e s p e c t logged review  Fordham  to  and  with  low  the  fall  through 1971;  Petticrew  Sullivan  low  populations  areas i s i n the e a r l y of  germination  1977).  and  of  spring. seedling  9 establishment,  concluded  c o n d i t i o n s are  likely  o f s t u d i e s have not different  more d e e r  through  t o be  all  determined  time  higher  number  early  spring,  y e a r and  to breeding  hypothesis that populations  of  claim),  then  1977,  live-trapped grid  was  should  t o November and  March  every  located  two  be  From  April  1978,  a third  grid  was  each  checkerboard  i n t e r v a l s marked t r a p was  apparent  the  spring,  designed  (logged)  Sadleir  to t e s t  habitats than  do  1971  and  the  support forested  between  these  Sadleir  1974  1975,  weeks  1978,  two  49  1976,  1.1-ha  March  grids  and  another  at  w i t h i n a 2-m  the c l e a r c u t  and  March  the Loon Lake s t u d y  trap stations tape  on  and  were l o c a t e d  string  to  ( F i g u r e 1.4).  r a d i u s o f each  One (Burn April  area. at  station.  to  were  w i t h Longworth l i v e - t r a p s .  t o November 1977  by f l a g g i n g  placed  METHODS  March t o December  to A p r i l  operated  grid,  and  similar..  i n the f o r e s t  study a r e a ) .  live  there  densities.  demographic d i f f e r e n c e s  MATERIALS AMD  November  in  density, recruitment, reproduction, survival,  growth parameters  From May  If  s h o u l d be  Peromyscus  p o p u l a t i o n s ( a s P e t t i c r e w and  mice  presumably i s  in particular,  c h a p t e r was  clearcut  majority  deer  purposes.  seasons  of the  temperature The  which  a r e a s , then t h i s  I f t h e r e a r e no  and  of  mice on l o g g e d  density  habitats. two  the  study r e p o r t e d i n t h i s  widely-held  moisture  for direct-seeding  when p o p u l a t i o n s d e c l i n e The  seedbed  optimum i n t h e s p r i n g .  h a b i t a t s d u r i n g the  the most c r i t i c a l are  that  On  15.2-m OneTraps  10 were b a i t e d batting checked  with peanut  was  butter  supplied  on d a y s  as  and  Purina  bedding.  2 and  3,  and  mice  captured  lab  Traps  chow.  Terylene  were s e t on day  then l o c k e d open  between  1,  trapping  periods. ftll  deer  balances,  sexed,  and  fish  tags.  fingerling n o t e d by  palpation  v a g i n a l openings  to  sampling.  Hilborn  avoid  for  a  the  were  determined  weight;  age  (1965),  j u v e n i l e s and  each  body  weight.  g ; and  mice  pooled together) throughout considered  in  clearcut The  enumeration cf a  random  simulation acccrate  o r more o f  classes  of  were  used  and  the  animals 0-12  g in  by  Sadleir  Fordham  (1971):  two  age  classes  of  juvenile  and  subadult  age  the r e s u l t s  t o be y o u n g a n i m a l s  and  discussion.  recruited  during  season.  I n t h e a p p r o p r i a t e f i g u r e s and designated  80%  been  these  classes  the breeding  (animals  to  of  g.  (1967),  and  are  by  Juveniles  have  Healey  I refer  juveniles  Age  a d u l t s >17  adults  Juveniles  by  assumptions  i n which  sampling time.  (1966),  adults.  condition  was  females. determined  design  c l a s s e s o f deer  Britten  numbered  techniques provide s u f f i c i e n t l y  s u b a d u l t s 13-16  Two  were  the  e t a l . '(1976) d e m o n s t r a t e d  by  Pesola spring  serially  noting  statistical  trapping  animals are caught  and  mammaries o f t h e  model t h a t e n u m e r a t i o n estimates  with  on  I n f o r m a t i o n on b r e e d i n g p e r f o r m a n c e  parameters  technigues  weighed  ear-tagged  o f male t e s t e s  and  Population  were  by a  letter:  ( l o o n Lake) -  forest  -  tables, A;  each  clearcut  of the g r i d s i s (Burn)  -  B;  C.  d a t a a n a l y s i s i n t h i s s t u d y i s c o m p l i c a t e d by  t h e same  11  animals  being  Consequently, which the  chi-sguare  the samples a r e not  sex  ratios.  statistically  valid  difference  used  to  For  in  completely  between t h e s e  periods.  utilized  f o r data i n  independent.  reason,  are used  for differences  the  as an  between s e t s o f d a t a .  test  sampling  Examples  i n breeding c o n d i t i o n , s u r v i v a l this  but  several  a n a l y s e s have been  p r o p o r t i o n of animals  and  of  captured  tests  may  indication  Chi-square  p o p u l a t i o n s of deer  mice i n  rates, not  of t h e  forest  be  degree  analyses  i n v a r i o u s demographic  are  were  attributes  and  clearcut  ha b i t a t s -  BESULTS Trappafcilty The  demographic  populations  is  individuals trappability  in has  analysis  based a  on  given  been  of  the  these  assumption  population  are  defined  by  Krebs  at  i / No.  forest  and  that  most  captured. et  al.  clearcut of  the  Maximum <1976)  as  present  at  follows:  trappability= Ho.  actually  caught  time  time  i  This  method i n c l u d e s a l l c a p t u r e s and  upwards  the  trappability  trappability  t h e r e f o r e , tends  estimate.  i s a l e s s biased estimate  known t o be  Minimum  to  bias  unweighted  since i t eliminates  first  12 and  last  This  captures  estimate  individual  was  of t r a p p a b i l i t y  by  estimates 1.1.  i n Table  deer  i t  animals  with  long  capture  f o r the  three  expected  trappability difference  was  above 75%  clearcut  always  between  study  males and  and  for  each  is  not  so  histories.  maximum In  the  Both are  trappability  forest,  minimum  years.  areas,  estimate  this  There  was  females i n the  of  given  in a l l three  70%.  above  twice.  value  i n each year  a l w a y s above 7 0 % .  was  the  populations  once o r  one  lives  i n most c a s e s ,  t r a p p a b i l i t y was on  only  long  and  mice  provides  only  how  As  higher  unweighted  hence a l l m i c e c a u g h t  regardless of  influenced these  and  For  very  of  little  forest  or  clearcut  study  areas  populations. Population The  and  recruitment  p o p u l a t i o n changes  similar The  density  but  not  i d e n t i c a l and  d e n s i t y of the f o r e s t  The  1975  with  the  first  breeding  breeding.  The  per  recruitment until  months.  season  late  during  October.  mice and  then  Numbers  were  of  The  at  the  as  14 a n i m a l s  season.  In September,  the  autumn i n c r e a s e  males and  in  the  16 t o 20  start  Figure  1.5.  of the  study  during  irice a t 1.0  season,  of  and  0.9  1975.  which  Host lasted  declined overwinter  during  con meneed breeding.  females  breeding  juvenile  per  ceased  the  the end  male  season during  breeding  1.1  in  were  separately.  animals  averaged  population  of b r e e d i n g typical  shown  breeding  1.1  recruits  is  breeding  averaged  of  be d i s c u s s e d  i n c r e a s e d t o 23  down t o 8 a n i m a l s stable  will  recruits  t r a p p i n g week o f occurred  so  three  commenced a t  Density  number of  the  population  population consisting  four  female  for  to  1976.  in The  number  trapping and  recruitment  16  there into  week was the  13 population. March to  Density  1977.  again  Breeding  began i n A p r i l  32 a n i m a l s i n J u n e .  c e a s e d i n September. and  1.2  females  recruitment  Figure study  1.5.  trapping  during  The b r e e d i n g  to  35  density  time  of  was l e s s  increased  was s t a b l e a t the  breeding  2.2  than  are also i l l u s t r a t e d i n  14  a t the s t a r t deer  mice  end o f b r e e d i n g .  There  the  fall  and t h e n t h e number o f a n i m a l s d e c l i n e d o v e r  of  1975-76 t o 17 m i c e .  period. week  of  juvenile  during  R e c r u i t s averaged breeding  rest  of  the  There  during  the  breeding  1.6 m a l e s and 0.9 f e m a l e  season.  recruitment  the  week o f  recruitment  declined after  then  The number o f  season.  was some a d d i t i o n a l  of this  and  breeding  1976 and was s t a b l e  the  i n 1976.  3.2 m a l e s and 2.0 f e m a l e s p e r t r a p p i n g  in  Most  and  r e c r u i t s averaged  Density  males  season.  breeding,  dramatic  s e a s o n commenced  towards  averaged  week o f b r e e d i n g  the  i n density  Density  t o 14 a n i m a l s i n  The number o f m i c e d e c l i n e d a s  c h a n g e s on t h e Burn g r i d  i n 1975.  increased  per  increase  Population  and t h e  The number o f r e c r u i t s  occurred  typical f a l l  declined overwinter  winter  started  reproductive per t r a p p i n g  was t h e t y p i c a l i n c r e a s e i n  i n t o the population  i n September  1976.  The  number o f m i c e d e c l i n e d t o 16 i n December 1976 b u t i n c r e a s e d 20  in  half  the  s p r i n g o f 1977.  of t h e b r e e d i n g  population.  The  season  average  1.8 f e m a l e s p e r t r a p p i n g fall  Density as  new  Density  week  declined  mice  of breeding  during  recruited  number o f r e c r u i t s  increase i n j u v e n i l e recruitment  animals.  increased  was  season.  which r e a c h e d  overwinter  to  the f i r s t into  the  1.9 m a l e s and There  was  a  a peak a t 44  t o 18 a n i m a l s i n March  1978. The  population  f o r t h e Loon L a k e c l e a r c u t i n 1977 i s  shown  14 in  Figure  1.6.  increasing  to a  number  of  Breeding peak o f 25  recruits  week o f b r e e d i n g was  similar  and  began  was  season.  mice  in  as  breeding.  late  The  l a c k of a f a l l and  May  with  density  The  average  females per  trapping  July.  males and  recruitment  Density  early  2.6  to t h a t of the f o r e s t  1977  in  1.9  i n c r e a s e i n numbers  Burn p o p u l a t i o n s  occurred  throughout  declined overwinter  to  16  in  the  1975  time  asimals  in  of  March  1978. The  average  forest  and  on  Burn i n  the  and  20-2  23.3  at  density  on t h e  clearcut  and  Loon  Lake  slightly  higher  reflected late  the  in  number o f  fall  15.8  1977.  Thus, t h e r e  deer  mice  three  animals  on  recruitment  19.6  forest  29.9  of  and  the 16.6  the  Burn,  was  very  little  forest  and  t h i s study.  The  Burn i n 1975  onto the  in  on  between  years  the  was  i n the  forest,  the  o f each  hectare  in the  of  during  burst of  summer and  22-3  density  habitats  mice per  B u r n i n 1975;  1976;  d i f f e r e n c e i n the  of  and  c l e a r c u t area  1977 in  the  year^  Beproduction The  best  activity fesales start  to  (Krebs e t a l .  i s about t h r e e  large  nipples  my  three  In 1915  - 23  the  use  for  i s probably  1969).  a c t i v e breeding  have been u s e d t o for  to  of a p o p u l a t i o n  of  which  variable  and  the  the  breeding  percentage of  T h i s measure  by t h e  weeks.  determining  underestimates  l e n g t h of the  gestation  Percentage of females  p e r c e n t a g e o f males w i t h  determine the l e n g t h of  lactating  the  the  period,  with scrotal  breeding  medium testes season  populations. forest,  veeks;  1976  the -  16  length  of the  weeks; 1977  -  breeding 22  weeks.  seasons On  the  were: Eurn,  15  the -  duration of the  16 weeks; 1977  breeding seasons  or  At  those  interval  deer  of animals  of the  two  o f one  year  first  at  Looking  significant  measures o f  male  If  1977.  males  years  we  of  breeding  There  in the  was  between  in no  Burn s t u d y  area  performance  for  we  males i n b r e e d i n g little  seasons.  Burn.  This  time  of t h e s t u d y  area.  we  see  1976  significant  on  forest  breeding  the in  when  was  no  However, t h e r e  1977, a d i f f e r e n c e  females  1977  study.  There  allowed  similar  habitats,  during  with  a  juvenile the  two  significantly the  Burn  p o p u l a t i o n i n 1 9 7 5 and  1976.  but  difference  lactating  Burn  was  on  not  statistically  i n proportion of  breeding  areas.  compare b r e e d i n g  population  In  adult  continued  T h e r e was  same  b e e n compared  and  in this  were compared.  that  females  the  i n p r o p o r t i o n o f a d u l t males i n  of t h e  populations proportion  juvenile  breeding  r e s p e c t i v e breeding  between  statistically  significant.  adult  variation  was  with  at the  p o p u l a t i o n s a t the  breeding  trend  forest  clearcut  forest.  compared  clearcut,  least  breeding  forest  the  greater  This  the  with  clearcut  at  a f t e r l o g g i n g or burning  any  were more j u v e n i l e compared  in  differences  condition during  Lake  Thus, t h e  mice a t Loon L a k e has  populations  comparison  were  13 weeks; 1976  1977).  population of 1975  Loon  weeks.  forest  three populations during t h e i r  the  the  15  for  i n the  1 . 2 g i v e s two  Table  The  lasted  were: 1 9 7 5 -  seasons  weeks.  l o n g e r than  Loon L a k e i n  the  20  o f mice l i v i n g  length, (and  -  1977  in  breeding  see  performance between a significantly  higher  c o n d i t i o n i n 1976 t h a n variation  in  years  percentage  in either  juvenile  for  male  the of  1975 or breeding  16 performance  between  proportion of adult 1976  compared adult  in  compared  higher  i n 1977  1976.  There  and  with  lactating 1975  that  b u t was was  p o p u l a t i o n had  males w i t h  in  197 5 o r  Similarly,  was  proportion of adult  and  was  different  from  was  j u v e n i l e f e m a l e s on  the  also  that  in  i n percentage  annual  t h a n i n the f o r e s t i n 1975  both h a b i t a t s in  in  1976-77.  a l l years than  of  a n i m a l s b r e e d i n g was  in  both  but a b o u t  More f e m a l e s  were  i n the f o r e s t s i n 1S76  The  variation  in  Burn. on  t h e same number i n breeding greatest  f o r males and  of  this  summary, t h e r e were more m a l e s i n b r e e d i n g c o n d i t i o n  Burn  of  greater  d u r i n g the years of  little  in  proportion  proportion  difference  females i n the f o r e s t there  The  testes  significantly  This  not s t a t i s t i c a l l y  the highest  scrotal  1977.  i n 1976.  not a s i g n i f i c a n t  study.  Burn  Burn  juvenile  with that  juvenile  the  The  females i n the f o r e s t  breeding  In  years.  1975  on  the  proportion  for  females  habitats.  Mortality Mortality from  the  Temporal  early  changes  each  survival  rates  rates  for  significant  it  are  is  differences  for  includes  are the  emigration.  measured trappable  a l l males and  breeding  (summer)  and  g i v e n i n T a b l e 1.3.  summed o v e r a s e a s o n time  survival i n  so  disappearance  by  direct  population  survival.  survival  seasons  i s r e p r e s e n t e d by and  include  populations  (winter) are  and  study  population,  in  juvenile  Minimum three  this  trappable  enumeration, and  in  w i t h an i n d i v i d u a l  trapped.  There  in survival  These  non-breeding average  mouse b e i n g  were  between  f e m a l e s i n the  no  rates  tallied  statistically  habitats  for  both  17 males  and  better  i n the  and  1976  the  forest  during in  females-  but  forest this  of  of  during  winter  better 1977  compared  difference  males This  1975  was  not  f o r m a l e s on survival  survived  1975-76 variation summers. 1975  and  in  In t h e 1976  statistically Early relating  female  that  recruitment  summers o f  i n 1977-  1975  H a l e mice i n  counterparts  1977-78 b u t  on  this  the  was  Burn  reversed  of females during  nearly  b e t t e r than  of  male  identical-  those  in  the  However,  the  forest  the  deer  nice survived  in  the  Burn.  The  previous  year,  significant. only  forest in  i n 1976-77 and  survival  was  similar  the  survival  on  There the  female deer  i n the  final  between  survival  o f young i n t o  possibly lactating  year  and  in  the was  1977-78. a  winters  of  very  during  this  of  the  little three  better  in  difference  was  1977.  be  measured  by  the  trappable  population  females  was  with  survived  and  6Q%  females  Burn  mice  1975  may  for  when 65%  between  Burn.  this  This trend  1975-76  87%  difference  but  in  significant differences  with  on  much  i n 1976-, S u r v i v a l a p p e a r e d h i g h e r  statistically  significant  juvenile  number o f  than  forest, than  the  slightly  1977-78-  compared  1976-77  their  1976-77 was  significant  and  reversed  Total survival  were i n t h e  trend i n winter  d e e r mice s u r v i v e d  Burn d u r i n g  1976-77 and  population  with  statistically  the  of  forest  in winter  the  Burn s u r v i v e d  i n summer  similar  of  1975-76 and the  The  on  1975-76-  f e m a l e s on the  than  d i f f e r e n c e was  winters  winter  winters  general,  s u r v i v e d b e t t e r than  the  the  In  (Krebs  an  index to  1966):  index= NO.  sttall  mice i n week t / Uo.  females with  medium  to  large  18  n i p p l e s caught  Small  mice  i n week  were  t-4  defined  gives the  mean i n d i c e s f o r  breeding  season  the  breeding  was  3-5  we  season  times  Loon Lake find  and  survival  a  little  With  the a d d i t i o n of  areas.  In  slightly Burn the  the  1-5).  to  In  Both  after  season  index  on  those  of  expected into  are  listed  i n Table  if  the  time  the  and  the  Burn  compare Burn  compared  but  the  (1975),  deer  mice  the  three  the study  survival  w i t h 0.86  for  was the  of breeding increased  the  forest  index  the p o p u l a t i o n a f t e r forest  In  Burn p o p u l a t i o n .  on  population  forest  populations  was  breeding  (see F i g u r e  population  p o p u l a t i o n on  Burn  the  youngon  1-4  survived  the Burn  or a t Loon  gained  juveniles  d u r i n g the  breeding  season.  recruited  estimated  in  of e i t h e r  the f o r e s t  female  the  and  juvenile  a t t h e end  Burn,  of  forest  little  1.14  during  I f we  forest  Sable  the breeding season,  early  with  juveniles  number  and  at  g.  survival  t h a t of the  very of  the  compared  the b r e e d i n g The  of the  More j u v e n i l e s e n t e r e d  1977,  juvenile  one-half  changed  17  of recruitment  twice that of  Recruitment  1.07  than  Lake.  than  the  mice.  Burn  better  those  higher i n the f o r e s t  index  end  than  populations  of r e c r u i t m e n t a f t e r  1976,  deer  three  early  more than  more  less  t h a t of the f o r e s t .  with  survival  unchanged. on  the  1975,  1977  those  to t h e  than  was  and  indices  of  higher  data o f  up  as  s u c c e s s f u l pregnancies and  each  was  observed  number o f j u v e n i l e s  p o p u l a t i o n up  1-5.  ft  pregnancy  lactating  of b i r t h  t o one was  of a l i t t e r .  The  month a f t e r  considered  during the  which  were  breeding  successful  p e r i o d f o l l o w i n g the  forest  population  had  19 a  greater  poor In  number  recruitment 1976  and  pregnancies population which end  o f j u v e n i l e s compared  1977,  but  the  than  on t h e  breeding,  habitats.  with  into  a lower of  the  surviving  Burn  very  there  was  recruits  t o one  little  as  little  which  reproduce.  This difference  sample the  sizes.  poorest  breeding  males was  for Of  entering  juvenile juvenile  between  surviving  season  of a  4 males and with  female  significant  was  the  recruits  1  females  the  forest  surviving  because o f  surviving which  given  3  between y e a r s ,  males  animals  between  and  animals  1977  For  the  variation  compared  not  Burn.  month b e f o r e  year  compare v a r i a t i o n  of breeding,  summary, t o t a l  statistically  summers was  no  had  very  to  small  1976  las  during  the  s u r v i v e d and  bred  the p o o r e s t  year  for a l l  3  areas. In  not  I f we  season.  b e f o r e t h e end study  had  year  i n 1976  young o f t h e  population  the  difference  t o the p r o p o r t i o n o f  population  to breed  on  and L o o n L a k e i n 1977.  was  but a  number o f s u c c e s s f u l  becoming r e p r o d u c t i v e d u r i n g t h e b r e e d i n g  year.  cf  significant)  1975-76,  slightly  male and  higher f o r  female  I n summer the  favour  c f the  from  t h e two  the  first  compared  Burn  animals  h a b i t a t s showed no  two  with  forest  y e a r s but those  Burn  s u r v i v a l was  i n the f o r e s t  1975-76, m a l e s s u r v i v e d b e t t e r on in  i n 1975  with t h a t  p o p u l a t i o n s up  there  respect  had  proportion  Burn,  Similarly,  habitats  forest  a higher  were r e c r u i t e d of  and  of s u c c e s s f u l pregnancies  1977,  population  male and  the Burn but  i n 1976-77 and  females  i n the f o r e s t .  female  population.  difference  higher  During this  was  1977-78.  in  (but the  survival winter reversed Females  i n winter s u r v i v a l i n  s u r v i v e d b e t t e r i n 1977-78  Total  survival  through  the  20  study  showed  clearcut Burn in  very  little  habitats.  in  1975  Early  but t h i s  variation  juvenile  was  between  survival  lower r e l a t i v e  was  the  forest  higher  to t h a t  and  on  i n the  the  forest  1576-77.  Growth Growth r a t e s within growth  may  populations  be of  used  as a f u r t h e r  Peromyscus m a n i c u l a t u s .  t o be c o n s i d e r e d a r e s e x u a l  growth  rate  regressed  on  at  variable.  sexual  mature  as an  animals  in  a  mature; in  Hy  age  have a t l e a s t class. age  weight  class  classes i n a similar  subadults  13-16g; and  The illustrated  mean  The  aspects of  body  average  percentage  assume  body of  may  o f which  are c a l l e d  less  than  in  a  i n Figure  1.7.  and  mature  adults  lowest  I e s t i m a t e d the weight  to  sexually  50% a r e  must  weight  limits for  previous  I n t h i s s t u d y , j u v e n i l e s were 0-12g  of  be u s e d  subadults,  s u b a d u l t s ; and  mature i n the  weight  sexually  j u v e n i l e s are never  manner d e s c r i b e d  weights  weight  demographic  criterion,  o f weight c l a s s e s  adults >  weight,  body  important  The  503* o f mice s e x u a l l y  1977).  an  of a better  Using these c r i t e r i a ,  conditions  and  limitations for juveniles,  classes  (Sullivan  by  is  series  groups of i n d i v i d u a l s  t h e upper  and  of  seasons.  i n d e x o f age,.  determine the weight adults.  maturity  Owing t o t h e l a c k  must be used  maturity  body w e i g h t ,  d u r i n g b r e e d i n g and n o n - b r e e d i n g Age  index  study  i n weight;  17g. male  and  female  deer  Female body w e i g h t s a r e  mice  are  complicated  u n d e t e c t e d p r e g n a n c i e s but a r e p r e s e n t e d h e r e f o r c o m p a r i s o n  o f a n i m a l s i n t h e two significantly  habitats.  different  because  None o f t h e i n d i v i d u a l of  the  broad  means i s  confidence  21 intervalsweighed  Male  deer  up t o one  mice  gram more  in than  d u r i n g t h e summers o f 1975 and in  the  summer o f  the w i n t e r s . each  1977  on  the  and  a t Loon L a k e  heavier Lake  in  In  habitats, there rate  is  dependent  variables  may  covariance  period  body  be compared  was  animals l e s s  on  study  done f o r growth r a t e  t h a n 18g f o r t h e  populations.  There  g r o w t h r a t e between three  years  however,  of  that  counterparts in  1977.  between  T h e r e was  growth  population  deer  and  study.  twice  a 1976  were  of each y e a r .  Loon  no  areas.  An  f o r each o f the  significant  and between  1975  and  subseguent similar  forest  and  differences i n  populations  i n 1976  of  weight o f  f e m a l e s had  faster  these  analysis  and  significant  growth  for  cn body  season  between  Since  It i s biologically  as f a s t  highly  differ  than  during  the  significant, their  Burn  and 3 t i m e s a s (p<.01)  fast  difference  1977 a s t h e g r o w t h  declined.  rates  should  were  1977-78  mice  rates.  M a l e s and  mice grew s l i g h t l y  i n 1975,  r a t e o f Burn a n i m a l s The  1975-76 and  regressed  t h e Burn and f o r e s t  this  forest  1975  However, f e m a l e s  regressions  breeding  o f recruitment each year.  during  trend.  i n growth  g r o w t h r a t e s and have been c o m b i n e d Burn  the Burn.  weight,  between  during  m i c e were h e a v i e r  growth c o n d i t i o n s f o r a n i m a l s  must be v a r i a t i o n  similar  differences  a l l cases,  to t h i s  counterparts  T h e i r w e i g h t s were  than i n the w i n t e r  males were a n e x c e p t i o n  cn the average,  clearcut  more i n the w i n t e r s o f  summer  To show t h a t  1976.  female f o r e s t  i n 1977-78.  the  their  w i t h a n i m a l s on  B u r n weighed  forest,  but showed c o n s i s t e n t  Similarly,  summer compared  the  of  individuals  be h i g h e r  comprising  the  t h a n t h o s e on t h e l o g g e d  forest  area,  and  22 this in  difference age.  s h o u l d be  Mean  growth  confidence l i m i t s As  a c c e n t u a t e d as t h e  rates  (adjusted  f o r males and  the Burn  Growth  i n both  rates  declined  the  same l e v e l  for  both  sexes.  females, that  but  are  maturing  1.9  (a s i m i l a r  always 1975.  remained in  at 1S77  grew f a s t e r  than  much l o w e r  than  was  interval  of  one  year  variable f o r determining  a t t h e same age  in different  little  of e a c h  Burn  sample  and  Burn  i n both  on  In  summary,  Bice  on  statistically t h e i r Burn  the Burn.  1976,  I f we  h a b i t a t s i n 1975  2 grams l i g h t e r  than i n  and  clearcut,  significant.  little  was  very  raatcrity  the d a t a comparing  forest  because  of  matured  very  low  years, deer  at weights  up  to  1977. were c o n s i s t e n t l y h e a v i e r  although  Forest  c o u n t e r p a r t s i n 1976  showing  1976  (1S76).  There  compare d i f f e r e n t  animals i n the f o r e s t the  estimated i n  mice a t s e x u a l  a n i m a l s a r e somewhat m i s l e a d i n g sizes  In  habitats-  o f deer  The  f e m a l e s d u r i n g the  year i n the s t u d y .  d i f f e r e n c e i n body w e i g h t  in f o r e s t  areas.  f o r v o l e s by K r e b s e t a l .  p r e s e n t s t h e s e d a t a f o r males and  p e r i o d June t o August  after  o f growth  1.8.  in  i n the f o r e s t  a t s e x u a l m a t u r i t y f o r l i v e - t r a p p e d m i c e was  Figure  than  females  d u r i n g 1976,  increased  combined r a t e  same manner a s d e s c r i b e d  mice  for  at sexual maturity i s a useful  mice  weight  and  except  mice were  males a t Loon L a k e i n 1977  mice i n 1975  95%  and  logging). Age  the  their  animals)  rates of f o r e s t  habitats  the B u r n and The  o f t h e Burn  after  if  on  t o 13-g  advances  f e m a l e s a r e shown i n F i g u r e  p r e v i o u s l y d i s c u s s e d , growth  h i g h e r than t h o s e from  clearcut  and  difference  this  variation  was  m i c e grew 3 t i m e s f a s t e r 2  times  in  1975.  faster  in  not than 1977,  Deer mice i n t h e  23 forest Sex  and B u r n p o p u l a t i o n s t e n d e d t o mature  ratios The sex r a t i o s  from  of the three p o p u l a t i o n s  have  been  summed  g i v e s the proportion each p o p u l a t i o n .  of m a l e s and  statistical  males i n 1975 compared  similar  number o f m a l e s and f e m a l e s i n b o t h the  significantly  forest  greater  and  Lake  Burn  (0.67) i n 1975,  and was  the  forest  in  populations difference  (0.50) after  p o p u l a t i o n was  with t h e f o r e s t .  loon  Lake  (0.61) was  logging,  Thus,  habitats  both  proportion  statistically compared  the  Burn.  to that  of the  with that  that  Loon  when  o f the f o r e s t  of  year of Lake  (>0.60), and  significant  a  t o the  and  o f males  1976. had  their first  Burn  for  higher  in  populations  similar  for  1.6  There tas a  s i g n i f i c a n t l y higher than  1975.  had a g r e a t e r was  Table  comparisons  p r o p o r t i o n o f males r e l a t i v e  p r o p o r t i o n f o r Loon  succession  these  The B u r n p o p u l a t i o n had a s i g n i f i c a n t l y  of  1977,  estimated and  f o r each year o f t h e study.  number  This  have b e e n  t h e minimum number o f a n i m a l s known t o be a l i v e ,  data  In  at s i m i l a r weights.  the  this Burn  i n 1975.  DISCUSSION In been  t h i s study, t h e demographic a t t r i b u t e s  compared  I n f o r m a t i o n was of were  the  between  forest  obtained  at biweekly  snow-free p e r i o d s of  very  recruitment,  few  differences  reproduction,  and c l e a r c u t  1975 in  o f d e e r mice (logged)  habitats.  intervals  throughout  to the s p r i n g  o f 1978.  the  parameters  of  have  most There  density,  s u r v i v a l , and g r o w t h between  forest  24 and  clearcut  populations.  fluctuations Few  in  There  numbers o f m i c e ,  o t h e r s t u d i e s have been a s  have r e l i e d compare  upon a n n u a l  densities  have c o n c l u d e d clearcut 1966;  that  areas  and  Similar  t r a p p i n g f o r one areas.  concluded  (1954),  c l e a r c u t s compared (1956a)  found  following clearcuts. trapped  to  were  Hooven  mice  in  cutover  the  Tevis  (1956b),  Lawrence  Krefting  and  Ahlgren  greater  number  (2 t o  compared  with  Harris  the  and  fall,  in  forest.  censuses  in  more, b u t  not  1970;  in  1973)  and  several  Badvanyi (1950a) different months,  pine.  h a b i t a t s compared  (1966), Sims  and  areas aged  Black  (1 t o 3 months) o v e r 2 to  (1976) several  10 t i m e s more  with unlogged Buckner  on  Tevis  different  Hooven and  t h e r e were from  on  ten times higher  of l o b l o l l y  and  to  Ahlgren  by O r r - E w i n g  mice was  deer  sites.  (1973),  and  (1974) came t o t h e s i m i l a r c o n c l u s i o n o f a 10  times)  of  mice  on  burnt  clearcuts  forest.  (1968) i n A l a s k a , u s i n g a n n u a l  summer  1959,  mice  number o f mice on l o g g e d  trapping  forest  fall  trapping during 3 winter  mature f o r e s t  that  workers  deer  month, f o r 12 months, i n  after  (1969,  most  Martell  obtained  a t more f r e g u e n t i n t e r v a l s concluded  and  clearcut.  summer and  more  (Gashwiler  1974;  4 times  months  y e a r s and  the  forest  seasonal  These l a t t e r s t u d i e s  2 t o 3 times  number o f d e e r  with  3  six  in  on t h e  since  habitats.  two  Ahlgren  the  intensive,  the  night every  that  particularly  i n the e a r l y  results  Trousdell  however,  censuses  t h e r e are  than  Krefting  1977a).  in  were  concluded Krull  northern  i n the  t h a t a g r e a t e r number o f mice  (1970)  concluded  hardwood f o r e s t  statistically  censuses  that  significantly  from  annual  t h e r e were more,  early exists summer  slightly  shite-footed  25 mice  (Peromyscus sj>.)  In a s i m i l a r intervals of deer  over  mice  Petticrew their  and  between  3-year  Sadleir  presented  Sadleir  densities  approximately  40%  with  i n numbers  paper  sampling  more  reflected  are  and  those  that on  i n the censuses  be  Similarly,  hence, (1574). males  in  Recruitment  i n my  and  1,54  week  of  forest.  (1.47  breeding  r e t u r n e d each  spring  This  r a t e s o f P.  the  females  i n the f o r e s t  drawn  there  study  study  f o r October  of  males and  to  each  occurring  a  indicates  1.06  The  the  level that  females  density  the  year.  mortality  must be h i g h e r on t h e  Burn,  in  and  the  per  to  and  Sadleir  Burn  c f mice on  comparable  be  i n density  Petticrew  h i g h e r on  is  i n the  p o p u l a t i o n on t h e  by  in  the  to  a r e a s than  p e r t r a p p i n g week o f b r e e d i n g  seasons).  manicnlatus  was  when  appear  t h e r e were g r e a t e r f l u c t u a t i o n s  recruitment,  October  T h i s comparison  logged  the f l u c t u a t i n g  monthly  g i v e n by P e t t i c r e w  compared?  obvious animals  by  habitats.  at  d u r i n g June and  the g r e a t e s t i n c r e a s e i n number o f mice  fall.  than  difference  a l s o came t o t h i s c o n c l u s i o n i n  conducted  habitats It is  particularly  is  bimonthly  recently-logged  intensive  in this  i n t h e two 1.7.  This  was  habitat.  at  (1974) , what c o n c l u s i o n s would  shewn i n T a b l e  forest,  with  in clearcut  trapped  little  and  {1911*)  project  (1975)  found  forested  I f sampling  data  areas than  type, lovejoy  18 months and  and  intervals. the  forest  in forest  (2.08  seasons) trapping the  Burn  of  the  that  and/or e s d g r a t i o n Burn  than  in  the  forest. If then  the  s i z e and  i s this habitat  logged  clearcut?  g r o w t h o f m i c e was  a better Is  i t  area  possible  for  greater i n the deer  that  Bice  than  the c l e a r c u t  forest, in  a  i s less  26 desirable  habitat  predation  such t h a t  of  the  forest  i n terms of  onto areas  1975)  terms  in  individuals,  Columbia  During  and  the  juveniles that  of  Petticrew  and  to  Some f e m a l e  Experimental  (removal a r e a s ) colonize 1967;  by  these  1977;  T h e r e was recruits  in  a  (70.9%  -  not  (60.9% o f t o t a l 1977, respect  there to  was  areas  has  Fairbairn  recruits)  statistically  proportion  of  in  and  and  low,  juvenile  winter.  with  few  thought  mice  aggressiveness  are  of  the  1S67;  Fordham  1971;  and  Sullivan  1977).  1977;  p a r t i c u l a r l y immigrants, and  shown  Sadleir  1S74).  vacant  habitat  of  that  juveniles  (Sadleir  1965;  will Healey  1978). proportion  during  the  of  breeding  Loon Lake p o p u l a t i o n  significant)  difference  breeding  is currently  of the  fall  colonization  higher  recruits) (Figures little  It  successfully  Burn p o p u l a t i o n  total  age;  British  spring  is  Healey  the  southern  the  (Petticrew  mice  and  in low  tolerated,  significantly  the  (92-3% o f  be  mice  Fairbairn  from  open  Sullivan  1965;  maturity  deer  between  survival  changes  1974;  evidence  interactions  recruitment  the  j u v e n i l e s may  they a t t a i n sexual  then  (Lidicker  with  trappable  (Sadleir Sadleir  case,  out  dispersal sinks  through  season,  seasonal  population  deer  densities  surviving  as  to  i n f a c t , driven  t h i s i s the  aggressive  seasonally,  high  by  acting  If  vulnerability  sinks.  s e a s o n a l changes i n  adult  1975  be  of  breeding  determined  if  may  clearcut?  populations  fluctuate  densities  the  behavioural  Forest  c o v e r , and  subordinate animals are,  recently-logged or  food,  1.5  and  than 1.6).  between t h e  juvenile recruits.  two  This  juvenile season in  i n the In  in 1977  forest  1976  and  habitats  with  trend  is  also  27 reflected  by  four  higher  in  times  1S76  index  and  of  the on  1977,  annual  populations  the  there  survival  The  index  Demographically, to each o t h e r  respect  and  This and  to  was  variation deer  of animals  Burn i n  mice  is  the  years  of  they  in  number o f  has  usually  declining survival in  1976  not evident  o c c u r s a t the numbers  be  start  regulated  recruitment  during  typical breeding was  autumn i n c r e a s e season  much s h o r t e r  well  as  1975  and  greater thereby  the 1977-  than  These  recruitment increased  the  the  poorer  being  and  The  rates  a greater  in  both  but  this  which  includes low  of  summer animals  proportion  of  T h i s c o u l d p r o d u c e a much t o poor  length  of  Burn p o p u l a t i o n s  Burn  breeding  d e e r mice b e f o r e to a  juvenile  which r e s u l t s  population  p e r i o d s o f the  density  Bith  Fairfcairn  s e a s o n and  growth  The  fall  1976,  females.  in density. forest  Burn).  1977.  with r e s p e c t  t h a t o f the  of  or  season  longer  the  both  density  populations  breeding  there  in  d e c l i n e i n deer mice,  condition.  reproductive  on  s p r i n g of  1975  1976  1.8similar  i n average  during  the  Table  from  (at l e a s t  breeding  f o r the  this  clearcut  were g u i t e  most e v i d e n t  population  the  1977  the  the  was  Again  in  and  in  breeding,  of  of  male d e e r mice i n b r e e d i n g more t i g h t l y  difference  differed  m a l e s as w e l l a s  a result  a  and  spring  r a t e s o f m a l e s and may  1975  in either  the  of  i n the f o r e s t .  summarized  turn,  of  discussed  of  which  areas.  recruits  onset  than  i n demography f o r f o r e s t  habitats declined in density  (1977)  two  d i f f e r e n c e was  the  phencnencn was  1975  much l e s s  between t h e  of  habitats-  of early juvenile s u r v i v a l ,  forest  seasons the  end  higher  in  in  the (16  1976 weeks)  1977  population  may  the  as in  result  in  of b r e e d i n g  and  level  compared  28 with  years The  area  with  shorter breeding  first  was  1975  1977.  Both  males  in  year  and  after  the  these their  (1977) enter  population  Thus,  season  following  either  adult-juvenile  superior and  1975  can  support  during  is  or  ratio  a  during  then  since  have  the  the  of t h i s  higher  first  that  h a b i t a t with  mainly  this  habitat  (food, s h e l t e r ,  densities  fall  breeding  less  animals.  study.  to  are  that  of  Lake  some e v i d e n c e  declined overwinter  winters  Loon  interactions  alternatively,  number  and  females  mice were a b l e  the  provides  behavioural  unlikely  three  superior,  of  season.  males:6  16:8  male d e e r  This  greater  breeding 8  of  o r more unknown r e s o u r c e s  populations the  the  the c l e a r c u t i s a poorer  mice,  i n one  clearcut  was  proportion  compared  recruited  juvenile  logging-  because  explanation  is  in  during  i n t o the c l e a r c u t populations  subordinate  higher  succession  Burn j u v e n i l e sex  13:9-  prevalent  study  the  the  of  Burn  l o g g i n g a t Loon Lake  a significantly  year  population  of  after  of the  r e f l e c t s a g r e a t e r number o f male j u v e n i l e s i n  e n t e r i n g the  with  burning  the  recruits  compared  and  sith  This  forest  year  had  first  forest.  The  logging  first  areas  seasons.  of  etc.) latter  forest  to s i m i l a r  I f the  density  This  is  and  levels  logged  habitat  mice  should  the  density  of  persist. Very of  few  d e e r mice c n c l e a r c u t a r e a s  practical  purposes  s p r i n g i s the and a  s t u d i e s have p r o v i d e d  of  by  most i m p o r t a n t  Waldron  i n the  reforestation  temperature c o n d i t i o n s review  i n f o r m a t i o n on early by  spring.  direct-seeding,  t i m e f o r optimum (ftrnott  (1973), the  1973). majority  For  seedbed  the  moisture  However, a c c o r d i n g of d i r e c t  the  seeding  to to  29 date, i n Canada, has been c a r r i e d out i n the autumn. in  the northwest  r e g i o n s of the United S t a t e s , seeding has  done mainly i n the f a l l not  Similarly,  (Carmichael 1957;  Lavender  been  1958).  It is  s u r p r i s i n g , then, that f o r e s t e r s have concluded t h e r e t o be  a g r e a t e r number of mice on c l e a r c u t s , s i n c e most work has done  in  (1S5 6) mice  the  summer  and  fall.  Orr-Ewing  provided data f o r the s p r i n g months than  studied.  i n subsequent P e t t i c r e w and  summer and f a l l  S a d l e i r (1974)  to be i n the s p r i n g , and t h i s was  a  non-breeding  long  (Petticrew  and  season.  Sadleir  l o n g , there i s a steady mortality  operates  decrease  over  an  if in  showed  fewer  months i n the h a b i t a t s found  the  lowest  most pronounced  According  1974),  (1950a) and Hooven  which  also  density  been  to  these  after  authors  the non-breeding season i s numbers  increasing  as  the  monthly  p e r i o d of time.  When  breeding begins a f t e r long non-breeding seasons, the d e n s i t y so  low  that there should not be a s p r i n g d e c l i n e . . However, i n  my study, the s p r i n g breeding  d e c l i n e i n 1976 f o l l o w e d the  season on the Burn  (36 weeks).  longest  seeks-  of  not f o l l o w e d by a d e c l i n e i n  reproduction.  There  appears  numbers  to be no  between the length of the non-breeding season and or  decline  s»as  T h i s was the same l e n g t h as the 1S76-77 non-breeding  p e r i o d , which was onset  non-  The l e n g t h of the non-  breeding season i n the f o r e s t p r i o r to t h i s s p r i n g 29  is  absence o f a s p r i n g d e c l i n e i n d e n s i t y i n my  at  the  relationship the  presence  study.  Thus, the number of deer mice i s lowest and very s i m i l a r i n f o r e s t e d and logged a r e a s d u r i n g the s p r i n g with a s p i l l - o v e r of animals clearcut.  i n the f a l l  t e m p o r a r i l y c r e a t i n g a higher number on the  Consequently,  a  newly-logged  area  may  not  be  a  30 particularly  f a v o u r a b l e h a b i t a t f o r deer  mammals once t h e i n i t i a l by B a d v a n y i  (1973) a n d B u n n e l l  processes  and t r e n d s  of  mice  deer  clearcut seed  areas.  be  should  be  The  similar  to  cn c l e a r c u t  areas than  nor  of  clearcut  This  i n forest  work s h o u l d  mice i n f o r e s t  logged  areas  regions,  i s the s i m i l a r i t y  animals.  monitoring  of  In a d d i t i o n ,  populations  by t h i s  (1974) a n d S a d l e i r  be f o l l o w e d  of  P*  mouse  more d e e r  o f mouse p o p u l a t i o n s  areas  of deer  habitats.  i s not supported  and c l e a r c u t  recently-logged  stages  conifer  i n forest  (logged)  P e t t i c r e w and S a d l e i r  subordinate  serai  on  f i n d i n g of t h i s study  which u s e d i n t e n s i v e s a m p l i n g  not  occupying  controlling  c o n c l u s i o n t h a t t h e r e a r e 2 t o 10 t i m e s  years.  populations  populations  and a s s o c i a t e d d e m o g r a p h i c a t t r i b u t e s  those  Population  of forest  for  populations  p o p u l a t i o n s i n f o r e s t e d and  or  for  a s expounded  (1S76).  i n the study  small  i n the s p r i n g .  density  of deer  and Eastman  mice which a r e d e v e l o p e d  most i m p r e s s i v e  spurious  has o c c u r r e d ,  Therefore, techniques  applicable  particularly  in  observed  p r e d a t i o n i n deer  should  colonization  mice and r e l a t e d  over  The mice study  (1974), several  up by b e h a v i o u r a l s t u d i e s  areas are there  to  determine  sinks should  maniculatus  i n t h e s u c c e s s i o n of a logged  area  whether  for  dispersing  be  intensive  during  a l l the  to f o r e s t .  31  Figure of  1.1.  British  Location Columbia  of the  Research  four  study  Forest,  areas  at t h e  Maple B i d g e ,  B.C.  University  UBC  Research  Forest  Scale=  , one k m  33 Figure and  1.2.  A e r i a l photograph showing t h e l o c a t i o n  traplines  areas.  Scale:  at  t h e Burn and S l a s h  1:12,000.  clearcut  and  o f the  grids  forest  study  3k  35 Figure  1.3.  Aerial  photograph showing t h e l o c a t i o n o f t h e g r i d s  a t t h e Loon Lake study  area.  Scale:  1:12,000.  36  37 Figure trap  1.4. per  sampling  Live-trap grid station)  quadrats.  and  (1.1 ha)  location  w i t h 49 t r a p o f 36  (0.61  stations  m x 0.61  m)  (one seed  38  A  a  • • k  •  —tr—  A  •  •  •  •  A.  .—-A—  •  |  - trap  station  | - seed sampling  •  —A— 91.4  A  • A  • • A  quadrat  • A  A  •  •  t i.  0.61  A  • A  —A  m  i  A  A  •  ,  •  •  •  •  • —A  • A  •  A  • A  • •  •  •  •  A  •  *  A  A  •  k  •  •  A  •  *-  •  seed sampling quadrat  • A  i  m  •  15.2 1  m  39 Figure  1.5-  grids  during  seasons are end  of  breeding  Population 1975-78,  shaded.  breeding  females  on  forest  Peromvscus  Vertical  activity.  seasons.  (shaded) and  density  Histograms (unshaded)  Burn  maniculatus.  dotted Solid  amd  bars  Non-breeding  represent  vertical  bars  indicate  number  recruited  into  clearcut  start  enclose of  and  defined  new  population.  males  FOREST  4035 -  1975  1976  1977  1978  BURN  M  J  S 1975  N  J  M  M  J  S  1976  N  J  M  M  J 1977  S  N  J  M  1978  41 Figure during  1.6-  Population  density  on  Loon  1977-78, P e r o m v s c u s m a n i c u l a t u s -  shaded-  Vertical  dotted Solid  bars  breeding  activity.  vertical  season.  Histograms i n d i c a t e  females  (unshaded) r e c r u i t e d  Non-breeding  represent bars  start  enclose  number o f new into  Lake c l e a r c u t  and  defined  males  population.  season end  grid is of  breeding  (shaded)  and  M  J 5 1977  N  J M 1978  43 Figure  1.7.  Mean  male and f e m a l e periods Forest  weights  w i t h 95% c o n f i d e n c e  Peromyscus m a n i c u l a t u s  1975-77. ( A ) ; Burn  body  Sample  size  limits for  d u r i n g summer and  winter  above upper c o n f i d e n c e  limits.  (B) ; and Loon Lake ( C ) .  Weight in Grams  45 Figure  1.8.  male  and  size  above  Mean growth r a t e s w i t h  (June April  upper by  Forest -  confidence  female Peromyscus m a n i c n l a t u s d u r i n g  represented circle-  95%  15  confidence  closed (A); Burn  November);  - O c t o b e r ) ; C-1977  limits-  and  A+B-1976 (15 May -  Loon  1975-77-  Forest  c i r c l e and c l e a r c u t (B) ;  limits  (C).  (June - O c t o b e r ) ; October).  Sample  population  populations  Lake  for  by open A+E-1975  A+E-1977 (15  M A L E S  F E M A L E S  Ci) -r~>  o CD c/)  o  . 0 2 0 4-  .01 5  +  01 0 +  51 76  123  705  65  c .005  95  6e>  0 72  32  143  B  B  c  0 --  •+-»  B  c . 0 0 5 --  62  I  50  B  115 7d  B C  2  1975  1976  1977  1975  1976  1977  HI Figure  1.9-  confidence to  August  circle Burn  Median limits  body  f o r males  of each year.  and c l e a r c u t  (E) ; and l o o n  weight and  sexual  (C).  by  maturity  females during  Forest population  populations Lake  at  open  and  95%  the period  June  represented circle.  by  Forest  closed (A);  M A L E S  ti) .Iz! D •+-» CO  F E M A L E S  i  24 22  \  20  \ JT  CO  X  7  18  / /T  /  14  \  \  B  T \  1  B  o  A  A  o  \ \  \  16  _C CD  c  \  \  LO  -t->  4  \  B  B  B  12 1  1975  1976  1977  1975  1976  1977  -pOo  49 Table 1.1.  Trappability estimates for Peromyscus maniculatus on the three  study areas for 1975-77. Sample size i n parentheses. Maximum trappability i s the proportion of those known to be alive that are actually caught i n a trapping session. Minimum unweighted trappability estimates f i r s t and last captures and provides only one value for each individual regardless of how long i t lives.  Forest Males  Burn  Females  Males  Loon Lake  Females  Males  Females  1975 0.95 (19) 0.94 (19) 0.79 (37) 0.86 (22) Maximum  1  trappability  i g 7 7  9  y  6 Q  Q  ^  2  ( 3 g )  ^  5  ( 4 5 ) Q  Q > 8 9  ^  9  ( 3 2 )  Q > 7 4  ( 3 5 )  Q  ^  ( 3 g )  Q > 8 4  Q Q ( 5 2 ) Q  ^  9  ( 3 5 )  ( 3 g )  Q  ^  Q  ( 3 4 ) Q  Minimum  1975 0.86 (17) 0.84 (15) 0.71 (28) 0.79 (12)  unweighted  1976 0.87 (21) 0.87 (20) 0.74 (25) 0.87 (26)  ^  9 3  ( 2 1 )  trappability 1977 0.75 (37) 0.78 (20) 0.77 (39) 0.74 (27) 0.75 (22) 0.93 (13)  Table 1.2.  Proportion of Peromyscus maniculatus i n breeding condition on study  areas during the breeding season of each year. Sample size i n parentheses.  Year and Group 1975 Testes scrotal Adults  0.78  (74)  0.90  (40) 0.91  (43)  Juveniles  0.14  (21)  0.12  (25) 0.11  (28)  Nipples med-rlarge . Adults  0.59  (74)  0.84  (32) 0.74  (39) A-B*  Juveniles  0.13  (16)  0.00  (7)+ 0.05  (19)  Adults  0.86  (74)  0.82  (79) 0.91  (43)  Juveniles  0.21  (56)  0.34  (35) 0.11  (28)  Adults  0.56  (59)  0.68  (74) 0.74  (39)  Juveniles  0.00  (26)  0.00  (39) 0.05  (19)  Adults  1.00  (44)  1.00  (28)  Juveniles  0.00  (6)+  0.86  (14)  0.39  (51)  0.68  (37)  1977 Testes scrotal  B-C*  Nipples med.-large  1976 Testes scrotal  Nipples med.-large Adults  -  A-B**  51 Table 1.3.  Minimum survival rates per 14 days for the three study areas.  Sample size i n parentheses. Males Forest Season and group  (A)  Burn  Loon Lake  (B)  (C)  Summer 1975 Total  0.92 (84)  0.87 (52)  -  Adults  0.92 (65)  0.85 (33)  -  Juveniles  0.89 (19)  0.89 (19)  0.68 (34)  0.81 (126)  -  Total  0.78 (45)  0.64 (39)  -  Adults  0.83 (42)  0.65 (26)  -  Juveniles  0.00 (3) +  0.62 (13)  -  0.87 (70)  0.78 (49)  -  Total  0.85 (120)  0.87  Adults  0.88 (67)  0.89 (75)  0.82 (39)  Juveniles  0.81 (53)  0.82 (28)  0.86 (22)  0.85 (84)  0.80 (137)  0.83 (103)  0.84 (437)  0.81 (506)  0.83 (164)  Winter 1975-76 Total Summer 1976  Winter 1976-77 Total Summer 1977 (103)  0.84 (61)  Winter 1977-78Total Total  + Inadequate sample size to test for difference.  51a  Table 1.3 (continued)  Females Forest  Burn  Loon Lake  (A)  (B)  (C)  Total  0.92 (78)  0.86 (36)  Adults  0.92 (64)  0.89 (27)  Juveniles  0.93 (14)  0.78 (9) +  -  0.74 (42)  0.74 (62)  -  Total  0.90 (50)  0.87 (39)  Adults  0.91 (45)  0.90 (30)  Juveniles  0.80 (5) +  0.78 (9)  -  0.84 (75)  0.84 (101)  Total  0.81 (80)  0.89 (97)  0.86 (50)  Adults  0.88 (56)  0.90 (67)  0.89 (36)  Juveniles  0.67 (24)  0.87 (30)  0.79 (14)  0.76 (54)  0.86 (111)  0.87 (75)  0.84 (379)  0.85 (446)  0.86 (125)  Season and group Summer 1975  Winter 1975-76 Total Summer 1976  Winter 1976-77 Total 0.85 (75) Summer 1977  Winter 1977-78 Total Total  + Inadequate sample size to test for difference.  Table 1.4. Indices of early juvenile survival for the three populations. Ranges for indices of survival based on samples including 2 or more females. N= number of trapping weeks.  Forest  mean  Burn  N  Range  0.38  12  0-1.0  1.33  0.38  12  0-1.0  1.14  8  1.13  mean  N  Loon Lake  Range  mean  6  0-2.2  —  — —  1.34  9  0-2.2  -  -  -  0-1.0  0.86  8  0-1.0  -  -  —  13  0-1.8  1.07  12  0-2.7  -  -  -  0.87  12  0-1.7  0.62  11  0-2.0  0.82  8  0-0.8  1.24  16  0-1.7  0.84  14  0-3.0  0.88  12  0-0.8  N  Range  Breeding season 1975 Breeding season + to end of recruitment  Breeding season 1976 Breeding season + to end of recruitment Breeding season 1977 Breeding season + to end of recruitment  52  Table 1.5.  Number o f successful pregnancies during breeding seasons and  observed and expected numbers of juveniles r e c r u i t i n g i n t o populations up t o one month a f t e r breeding. Sample s i z e i n parentheses f o r observed proportion of juveniles surviving and surviving t o breed. N = number o f trapping weeks.  Total  N  Range Total  N  Range T o t a l  N  Range  Number o f successful pregnancies 1975  15  12  1-3  11  7  1-3  -  1976  8  8  1-2  13  8  1-3  -  1977  11  12  1-3  18  11  1-4  12  8  1-2  Expected number of juveniles 1975  67.8  49.7  1976  36.2  58.8  1977  49.7  81.4  54.2  Observed number of juveniles 1975  22  (32.4%)  39  , (78.5%)  1976  23  (63.5%)  30  (51.0%)  1977  38  (76.5%)  40  (49,1%)  Males  Females  Males  Females  1975  1.00 (5)  1..00 (5.)  1.00 (6)  0.50 (2.)  1976  0.00 (1)  0.67 (3)  0.67 (6)  1.00 (3)  1977  0.94 (17) 0.44 (9)  0.75 (8)  0.60 (10)  Proportion . . 1 surviving  1  Males  0.89  Females  (9)  0.80 (5)  Animals caught up to one month before end of breeding and survive a t l e a s t 2wks. Animals i n reproductive condition before end o f breeding.  54 Table 1.6. Sex ratios (proportion of males) i n the three populations of Peromyscus maniculatus i n 1975-77. Sample size in parentheses.  Forest Year  (A)  Burn (B)  Loon Lake _  ... (C)  1975  0.50 (210)  0.67 (279)  -  1976  0.46 (315)  0.46 (315)  -  1977  0.62 (468)  0.52 (599)  0.61 (343)  ** p<.01 significant difference by chi-square.  Comparisons _ A-B  A-C  B-C  A-B**  A-B**  B-C**  Table 1.7. Minimum number of animals known to be alive i n June and October of 1975-77 for forest and clearcut habitats i n this study and for 1968-70 i n a study by Petticrew and Sadleir (1974). Density i s number of animals per hectare.  Forest  Clearcut  June  16  14  October  22  30  June  14  15  October  18  24  June  27  29  October  21  37  Forest  Clearcut  June  9  10  October  22  26  June  28  37  October  30  32  1975  1976  1977  1968  1969  "after Petticrew and Sadleir (1974)  Table 1.8. Summary of the annual variation i n demography of forest and clearcut populations of Peromyscus maniculatus.  1975  Forest 1976  1977  1975  Burn 1976  1977  19.6  15.8  22.3  23.3  16.6  29.9  (males)  1.0  1.1  2.2  3.2  1.6  1.9  (females)  0.9  1.1  1.2  2.0  0.9  1.8  23  16  22  13  16  20  15  8  11  11  13  18  (males)  0.78  1.00  0.86  0.90  1.00  0.82  (females)  0.59  0.39  0.56  0.84  0.68  0.68  0.50  0.25  0.15  0.38  0.78  0.17  summer  0.92  0.78  0.85  0.87  0.64  0.87  -winter  0.68  0.87  0.89  0.81  0.78  0.84  summer^'  0.92  0.90  0.81  0.86  0.87  0.89  0.74  0.85  0.87  0.74  0.84  0.92  7.5  2.7  4.9  5.3  1.3  1.7  summer  18.3  18.8  17.0  17.2  17.7  17.0  winter  17.0  15.2  16.7  16.3  15.0  15.3  summer  19.5  19.4  17.8  18.3  19.0  17.2  15.4  15.8  15.8  16.3  14.9  16.5  Average density (per ha) No. recruits per trapping week of breeding season  Reproductive rate -length of breeding season (weeks) -number of successful pregnancies -proportion of breeding animals  -proportion of recruits surviving to breed Survival (adults and juveniles males females winter Average growth rates per day (xlO ^) Average body weight (g) males females winter  57  CH5PTEE 2  REPOPULATION  0? VACANT CLEARCUT  AND CONIFER SEED PREDATION  HABITAT  BI THE DEEB HOUSE  INTRODUCTION Conifer  seed  loss  f o r e s t e r s and w i l d l i f e century. bait,  or  An a l t e r n a t i v e repellent  r o d e n t s would be k i l l e d success  Poison  of  directly  species unknown  o r as t o x i c a n t s and  the  (see r e v i e w  application  of  part  tree  short  rapid  (Oashwiler  poison  over t h e area  of  applying  seed  such the  a  that seed.  control  1969; H o f f e r  a r e hazardous  of  Elimination of  and r e i n v a s i o n  1972; and Hooven 1975)on s e e d s ,  this  been s a t i s f a c t o r y .  periods.  i s incomplete  to  of  t h e use o f  scattered  the  problem  i n e f f e c t i v e because  f o r very  rodent p o p u l a t i o n  Bank and M a t s c h k e  baits  early  consists  to  a  by, o r r e p e l l e d f r o m , e a t i n g  surrounding areas i s often  as  grain,  method  considered  i s possible only  initial  1969;  been  these t e c h n i q u e s has seldom  b a i t s a r e now  rodents  has  managers s i n c e t h e  usually chemically-treated  toxicant  the  rodents  The main c o n t r o l method h a s i n v o l v e d  to b e s e e d e d .  The  to  Poisons, to  from  et a l . either  non-target  f a t e of these c h e m i c a l s i n the environment i s by Evans  toxicants  1914). and  In  addition,  repellents  to  the  direct  seeds has o f t e n  58  reduced  seed  The first  1941;  by and  by  deer  several Stickel  from  which  colonization  of  these e a r l i e r  results  and  1978).  Fairbairn  advocate  the  1946).  Why  poison  devoid  of  impossible? continually  mice  that  a  1976)  a d v i s e d t h e use  with  the  have  more  on  to  1967;  of  onto  physically  Sullivan  (Oregon  use  of the  direct  1977; to  chemical  keeping  days i s  an  virtually has  I t seems  been ironic  State University,  containing  be s e e d e d .  the  continued  when  a few  on  supported  a r e a s or t h e  success.  Report  reflect  problem  mice  years, poison b a i t i n g  areas to the  these  work  foresters  than  of poison b a i t s  a century of f u t i l i t y ,  with  Healey  1940;  from  m a n i c u l a t u s has  very l i t t l e  half  dealing  P.  of clearcut  forty  rodent  continues  (either  f o r rodent c o n t r o l ,  for  repellents  been removed  by  r e c e n t F o r e s t Research  control  be c o n c l u d e d  More r e c e n t  was  (Blair  of deer  then  for  For the past  1940's  areas  invasion  1965;  baiting seed  attempted  I t may  had  (Sadleir  depopulated  i n the  a rapid  habitat  1970).  of  poison b a i t s ) .  vacant  treatment of c o n i f e r  mice workers  animals  s n a p - t r a p s o r by  area  (Badwan 1969,  s t u d i e s t h a t t h e r e was  areas with  colonization  studied  Spencer early  germination  anticoagulants  Even a f t e r  chemical  poisons  philosophy of seeding  nearly and  foresters  and  rodent  populations. Few deer  studies  mice  on  present study of  a l l  be  the was  deer  satisfactory  have measured b o t h s e e d  designed  mice survival  completely  removal  (poisoned)  to t e s t  (simulated  and  poison  and t h e n  density  control areas.  the h y p o t h e s i s  of c o n i f e r seed.  depopulated  s u r v i v a l and  baiting)  that will  I f a poisoned  maintained  free of  of The  removal result in area  can  invasion  59 by d e e r  mice  survival  from  of  stocking  surrounding  conifer  seed  of a c u t o v e r  area.  should  MATERIALS Deer  ha g r i d s trapped  t o October  (G, H, every  forest  I , and  two  Grids  grids  G,  H,  (D  I , and  J)  and  and  E)  consequent  adequate f o r s u c c e s s f u l  AND  METHODS  and  March t o A p r i l  J  i n some a r e a s b u t  several  burning  slash  other  and On  less  1,4).  One  station.  Traps  trapping All  Q  grids and  area logged 1974.  were In  as  was  J  was  (G and  slash The  bracken,  Q,  49  I)  were 1975.  of  1973  burn  was  main c o v e r  was  fireweed,  and  G r i d s D and  which surrounded  (see F i g u r e s  grid, by  grid  live-  September  The  1.1  addition,  i n the f a l l  i n others. of  four  1.2  and  E  the  2.1a).  t r a p s t a t i o n s were l o c a t e d a t  flagging  placed within  tape a  and  2-m  string  radius  (Figure of  each  were b a i t e d w i t h p e a n u t b u t t e r , P u r i n a l a b chow,  Terylene batting 1,  1978,  abundant s u c c e s s i o n a l h e r b s ,  marked  live-trap  August  growth  west s i d e s o f g r i d  intervals  an  patchy  with  each checkerboard  15.2-m  grid  2 clearcut  i n August  were l o c a t e d i n t h e f o r e s t , north  L-shaped  and  were on  uniform  o r dead  an  manner d u r i n g  by  burnt  slash  1977  followed  day  the  weeks w i t h L o n g w o r t h l i v e - t r a p s .  trapped i n a s i m i l a r  and  be  then  mouse p o p u l a t i o n s From J u l y  2  regions,  checked  on  was  s u p p l i e d as bedding.  d a y s 2 and  3,  and  then  Traps  were s e t  l o c k e d open  on  between  periods. deer  mice  captured  were  weighed  on  Pesola  spring  60 balances,  sexed,  fingerling gained and  fish  by  and  tags.  ear-tagged  palpating  testes  and  noting  numbered  performance  the c o n d i t i o n  was  of vagina  niammaries.  1915, all  g r i d s G and animals.  and  E had  the s p r i n g o f  Seed  of  into  36  0*61  m x 0.61  {15.2  sampling  1978, grid  two  set  a l l trappable species of J each  trapping  recovery on  to  small  in  remove of  1977  mammals  week.  (Figure both  to  1.4).  grids  were  weighed  number o f s e e d s .  plots.  In each  E q u a l amounts o f  (I  of early  t h e amount d e s i r e d  systematically  and  fall  J)  1977  (0.81  was  weighed  by w e i g h t  seed  Douglas the  kg/ha)  and  2 and  packaged  p e r s q u a r e meter o f g r i d  (area  o f 2500 D o u g l a s  s u b s e q u e n t l y used  a  kg/ha).  w i t h t h e mean v a l u e r e p r e s e n t i n g  t h e number o f s e e d s  plot,  during  o f 1978 .(0.405  S e v e r a l samples  T h i s v a l u e was  divided  i n a s u i t a b l e area f o r  i n the s p r i n g  m).  was  s g u a r e m)  located  seeding t r i a l s  = 8,361.3 s q .  obtain  231  to each e x p e r i m e n t , seed  according  seeds  m =  m g u a d r a t was  seeding t r i a l s  Prior  grid  HI X 15.2  were used  experimental  on a  continuously  the experimental g r i d s  and  seed  the  kill-traps  poison baiting)  populations Each  fir  (simulated  In the experiments during the e a r l y f a l l  were removed from  to  serially  I n f o r m a t i o n on b r e e d i n g  During the removal experiment  of  with  that  as a  f i r given  multiple  f o r e a c h o f t h e 36  plots  grid. In  seed  e a c h o f 25 r a n d o m l y  was  placed  a seed-sampling marked  by  i n one  chosen  plots,  a  known  o r more o f t h e 4 (0.093 s g .  guadrat.  Location  wooden t o o t h p i c k s -  of  The r e s t  individual  density m)  units in  seeds  of the a l l o t t e d  of  seed  was was  61  then  spread  area  of  accident over  by hand a s  that into  each  plot.  u n i f o r m l y as p o s s i b l e o v e r Care  the sampling  guadrat  on  a grid.  the seed-sampling  mice  any  them. the  seed e x p e r i m e n t  Sampling first  trial  was  period)  second  trial  grid  p l a c e d one to  covered  allowing  more s e e d  cover  was  prevented  were p r o p p e d  up  at l e a s t  one  by  placed  rain to  from allow  predators free access  grids  conducted  5 days  two and  fspring  under  week  before  weeks a f t e r  seeding  f o r the  s p r i n g p e r i o d s and period)  after  at 3  seeding  days  for  the  periodtrap in a central  potential  These  but  remaining  began.  seed-fall  measure  a f r a m e box  mesh)  and  i n each  experiments. of  then  t o throw  A plastic  seed  i n each o f the f a l l  (fall  I  areas  the  not  These covers  other p o t e n t i a l  They were p l a c e d on  first  taken  quadrate  disturbing and  was  the  natural  t r a p s were 0.37  position  seed-fall  during  sg.  m i n a r e a and  (2.5-cm x 7.5-cm s i d e s ) .  Hindow s c r e e n  the base with  seeds to f a l l  into  1 cm  on  mesh h a r d w a r e c l o t h  each these  composed (14 on  by  the  18 top  the t r a p .  RESULTS TrappabiIty  The based  on  analysis  the assumption  population by  of the c o n t r o l  (1976)  experimental  t h a t most o f the  are captured.  Krebs et a l .  and  individuals in a  Maximum t r a p p a b i l i t y  as f o l l o w s :  populations i s  has  given  been d e f i n e d  62 trappability= No.  actually  time  i  This  method  upwards  the  last  i s a less  by  these  estimates  spring  1978  difference  between  of  seed  grid.  seed  on  trappability trapping  of  of g r i d  effectively simulated  Experimental  survival  areas and  this  mice was  deer  mice.  (or  during the  so  experimental  my  Both  of  1977  and  animals  was  little  In  the  spring  on  both  on t h e  grids  but  experimental  c o n t e n t i o n that Douglas f i r I)  would  Consequently, fall  majority  i s not  There  time.  similar  grid  the  of poison  and  each  2-1.  much h i g h e r  support  t*ice.  for  histories-  experiment.  o f m a l e s was  J  value  lives  capture  at  grid  J  bias  unweighted  p o p u l a t i o n s i n the f a l l  fall  sexes  deer  at  and  of deer  my  not  lower  continuous  spring  the live-  experiments  mice and a c c u r a t e l y  baits.  poison halting.  To show t h a t seeded  the  removed  t h e use  two  i t  are given i n Table  These r e s u l t s  removal  long  long  the  trappability  female  to  o n l y once o r  e s t i m a t e s f o r c o n t r o l and  during  present  Minimum  p r o v i d e s o n l y one  how  with  for  were s i m i l a r  experiment,  of  experiments  Trappability  be  t h e r e f o r e , tends  estimate-  trappability  animals  to  hence a l l mice caught  regardless  influenced  known  biased estimate since i t e l i m i n a t e s f i r s t  c a p t u r e s and  individual  i / Mo-  trappability  T h i s e s t i m a t e of  that  a t time  i n c l u d e s a l l c a p t u r e s and  trappability and  caught  by  deer  mice  the use  are  effectively  o f p o i s o n b a i t s , one  compare i t w i t h  t h a t on  a control  eliminated  from  must measure  seed  area.  Comparison  63 of s u r v i v a l 1975  o f Douglas  f i r seed  i s shown i n T a b l e 2.2.  kill-traps  on  population  was  habitats,  seed  the  experimental  survival seed  clearcut)  was  week e x p e r i m e n t . and  a t what r a t e  or o t h e r removal Fall  grids, the  v e r y low,  Bhat  and  Figure two  were  2-Ta. sides  removed  by  resident  area.  both  with the removal  grids  areas  The  total  (61 i n f o r e s t throughout  o f t h e s e mice on  an a r e a s e t w i t h  and  34  the s i x clearcuts  poison  baits  methods?  was  1977. Grid  by g r i d  answered A map  J was Q  in  origin  a clearcut  (L-shaped)  so t h a t a l l a n i m a l s  could  predicted  be  response  results  shown  total  c f 41  mice  was  forest.  were t a g g e d Figure  and  place  of  illustrates  my  their  2.1b  the removal  2 removal  in  removed  periods  F i g u r e 2.2. from  grid  animals.  Q or other surrounding areas. end  of  grids the  area  (J)  (experiment  From A u g u s t  J , 36.65?  this  During  of  10 m i c e were r e m o v e d , a l l c o l o n i z i n g  the  bordered  of  period  at  in  shown  weeks b e f o r e t h e s t a r t  colonizing  surviving  is  These  non-resident, another  in  from  clearcut.  of the f i r s t  schematically  experiment  experimental area  of mice moving o n t o and  removal  experiment  i n the  determined.  the surrounding f o r e s t The  a  for this  trapped normally f o r s e v e r a l  experiment  grid  in  In  continuous  move o n t o  grids  the  on t h e c o n t r o l .  i s the o r i g i n  do t h e y  whereas  control  removal  immediate  question  August-September  are  were c o n t i n u a l l y  surviving than the  removal  Removal This  on  on  was  number o f m i c e c o l o n i z i n g on  c o n t r o l and  Animals  not manipulated  having even l e s s  on  There  was  21-24, a  these  the second  no  were  removal  animals conifer  12-day e x p e r i m e n t .  A)  Thus,  from seed the  64 removal  of a l l r e s i d e n t  higher  survival  These animals within  a  rate  (traps  fourteen fir  was  In  still  grid  not  from  result  in  a  cn a c o n t r o l  area.  surrounding  areas  Q,  repeated to determine  eaten  by  schematically  grid  B.  J.  On Two  set  days l a t e r  during  present  compared  trapping period grid  during  the  G,  on  removal  18-19, on  this  18  September  experiment),  o n l y 5% o f t h e  Douglas  w i t h 3% f o r t h e  control  of t h i s  and  mice  outlines  September  t h e a r e a , and  1 from  colonizing  the  experiment,  4 new)  16  mice  had  again  colonized  of  this  removal  grid.  experiment,  J;  then  continuously  summary,  origins  was  4 i n experiment  I n the f i n a l  the removal  mice  2.3  mice had c o l o n i z e d  from  did  to that  by  was  removed from  were  seed  grid.  seed  Figure  3 and  were  relative  experiment  areas.  animals  J  period.  a t which c o n i f e r  p e r i o d s no.  (11  seed replaced  removal  poisoned  21  were  12-day  This  of  mice on g r i d  a  total  o f 99  six  weeks  mice c o l o n i z e d  removal  grid  J.  The  of these  mice  were a s f o l l o w s :  26 r e s i d e n t  mice on  32 mice from  grid  Q i n the f o r e s t ;  7 from  G;  and  a  continuous  a n i m a l s from  surrounding areas.  movement  of  of  the c o n i f e r  95%  Spring  of  animals  Thus,  onto a poisoned seed w i t h i n  grid  there  is  a r e a , and  a 3-day  grid 34  a resultant  new  loss  period.  Removal  P o p u l a t i o n s o f Peromyscus m a n i c u l a t u s highest  density  lowest  point  i n the f a l l i n the s p r i n g s  s e e d , and  removal  grids  fall  removal  experiment  1977  and  decline  generally over  T h i s annual c y c l e  is illustrated was  winter on t h e  i n F i g u r e 2.4.  performed  reach  d u r i n g the  their  to  the  control, Since  the  period  of  65 highest  population  depopulated of  area  may  when  areas.  (Arnott  baiting  seeding  Many small  was  out a f t e r  pre-baiting  replicated  my  the second  this  with  surviving  (grid  resident  of  the  grid  survival  of seed  removal  of animals  in  preventing  control  12-day  mice on  with  2.6  illustrates  and  Douglas f i r seed the t h i r d  was was  and  repeated eaten  during  f o u r t h removal  deer  mice c o l o n i z e d the r e m o v a l  control grid. 11  mice  (3  seed  was  In t h e from  s e e d e d on  still  final  grid  the  G,  this  conifer on g r i d  removal  J of  appreciably higher  was  area. not  Thus,  effective  to determine  removal  f i r  nc  of  mice.  the  Douglas  carried  During  o n l y 8.0%  i n an  L i v e - t r a p s were c o n t i n u o u s l y s e t from was  seeding  simulation  was  Again,  D).  area  seed-eating  direct  t h a t on t h e c o n t r o l  to deer  poison  s e e d i n g was  weeks p r i o r t o s e e d i n g  T h i s removal experiment which  I)  experiment.  compared two  number o f  J . . There  J d i d not r e s u l t  seed l o s s  at  the  are  1978.  C i n F i g u r e 2-5).  seed  seeding  done i n the s p r i n g  p e r i o d which a l l o w e d  grid  the  abundance  for  s p r i n g of  spring experiments,  16 mice were removed from  a t t h e end  time  poison before  (experiment  the  o f an  experimental  i n the  time,  on  a result  of  seedling establishment  to reduce  removal  period  and  Thus,  attempt  In  colonization  s e e d i n g s h o u l d be  pre-baiting  1975).  rapid  i s t h u s a poor  1973).  foresters  mammals by  (Hooven  fall  f o r germination  favourable and  The  Also, d i r e c t  conditions  the  have been s t r i c t l y  surplus animals.  logged  a  density,  April  area,  2. and  the  spring.  periods  April  2  to  only  7-4%  Q, and  Figure  7  five  with  t r a p p i n g p e r i o d of t h i s grid  rate  (experiment  After  p r e s e n t compared  5 from  the  3 new)  after  days, of  10%  21 the  on  the  experiment, had  again  66 colonized In  the removal  summary, a t o t a l  The  origins  grid  J ; 15 m i c e  new  grid. o f 48 mice  o f t h e s e mice  animals.  from  Thus,  grid  were a s f o l l o w s :  Q i n the f o r e s t ;  there i s  a  and  92.6%  eating  of  removal  9 from g r i d source  the s p r i n g ,  the  grid  14 r e s i d e n t  continuous  moving o n t o a p o i s o n e d a r e a d u r i n g area,  colonized  conifer  J.  mice  on  G; and  10  of  animals  repopulating  seed within  that  a 5-day  period. The c o l o n i z a t i o n small  mammals  gapperi) are  there of  (Microtus oregoni,  was a l s o  listed  the average  grid  I during There  fir  colonized  to the f a l l  the t o t a l  the f a l l  appeared  and s p r i n g  of  results  experiment,  of  individuals  numbers o f e a c h J  period  was  o f the  much  on e i t h e r  higher  grid  H or  experiments.  t o be no m e a s u r a b l e  seeds i n the s e e d - f a l l  These  removal  removal g r i d  numbers p e r t r a p p i n g  species  s p p . , and C l e t h r i o n o m y s  i n t h e a v e r a g e number  However,  which  than  Prior  difference  species.  three species  Sorex  other  monitored i n these experiments.  i n T a b l e 2.3.  was l i t t l e  other  o f t h e r e m o v a l a r e a by  natural f a l l  t r a p s on any o f  the  grids  of  Douglas in  this  study.  DISCUSSION In deer  these experiments I attempted t o m a i n t a i n a r e a s f r e e of  mice  experiment sere  in  a  used  continuously  simulation live-traps set.  of  poison  supplemented  baiting.  The  with k i l l - t r a p s  The e x p e r i m e n t s i n 1977  and  1978  1975 which used  67 only  live-traps  exceptions). Tables  1-1  s e t f o r two  Peromvscus  and  2.1)  and  readily  that  animals,  b o t h r e s i d e n t and  surrounding  alternative  design  continuously.  This  experiment  in  D  continuous every  trapping  areas,  would  1978  two  weeks  removal area  would  than  have  i f poison  temporary  application overlook  abundant  phenomenon was  evident  reported  every  with  that  poison  failed.  He  population bait  of deer  avoidance  possibility avoidance bait  concluded  avoidance.  results  of  this  captured  and  high  when  in  live-traps  the  area  1977  and  same e f f e c t trapping  traps  both  work  of  by  Tevis  to p r o t e c t seed  by  them.  poisoning  only  This  (1956c), killing  rodents  because  not of  seed  continuously  the  during  affect great  had the  survive  by  Thus,  the  because  to or l e s s than t h a t  avoidance d i d  who  California  c o n i f e r seed.  removal of animals  the  objections mice.  some i n d i v i d u a l s a l w a y s eat  of  from  these  avoidance  the  because  available  of  trap  associated the  with  predicted  number o f  experiments B  set f o r 4-night  as  only  removes p a r t o f  mortality of were  supply  to  An  removal  that  continue  study  periods.  in  of  grid  of  be s i m i l a r Trap  majority  more mice t o o c c u p y  have a v o i d e d  bait  have  removal  B  that  I  Douglas f i r r e g i o n  of i n e f f i c i e n t would  the  trapping  argued  allowed  of  mice and  and  (see  to t r a p the  However,  attempt  b a i t s i n the  trappable  the  experiment  food  possibility  minor  b a i t s were c o n t i n u a l l y k i l l i n g  o f c o n i f e r seed*  the  been  be  I n a d d i t i o n , some d e e r mice may the  captured  i s assumed t o have t h e  I t could  (with  unfamiliar traps.  consecutive  done d u r i n g  weeks  very  colonizing  have  and  poisoning.  enters  those  two  is  program  during  was  every  maniculatus  assumed  from  this  nights  (E)  mice  and  D  and  6-  68 night  (D) p e r i o d s . In removal  depopulated shortly  areas  after  (194 1)  studies  which  small  was  trapping  and f o u n d  a  Vleck  weeks.  the  townsendii.  concluded  that  removed.  Spencer  p e n n s y l v a n i c u s from  poisoned  grain.  and  of  density  of the given  Sullivan  (Blair  area  reached  levels  snap-  of the experimental  density  immigration rate  of  (grid  (1977b)  plot.  colonized  i n a period of  a s was f o u n d  removal  and other  into  by  could  experiments  not  small  1978), mammal  observed  remove a l l  by t h e u s e o f  1965;  Healey  and i n t h i s  study.  species  J) a c c o m p a n i e d t h e i n f l u x  much h i g h e r t h a n t h o s e  vacant  have b e e n o b t a i n e d  1946; S a d l e i r  Fairbairn  these  established  rate into  a hardwood p l a n t a t i o n  1940; S t i c k e l  1977;  A l s o , t h e movement removal  invasion  s m a l l mammals by  Hicrotus pennsylvanicus  Badvanyi  r e s u l t s from  Peroroyscus  i n the  extent  l e s s than the immigration  Hicrotus  Similar  an a r e a  F o r these s p e c i e s of v o l e s ,  the  Bartell  with  invasion  up t o t h e p r e - r e m o v a l  areas.  areas  population  (1953) removed  immediate  p o p u l a t i o n s was much  1967;  or very  been  in  mammals,  (1971) f o r 2 s p e c i e s o f H i c r o t u s and by K r e b s e t  a l . (1976) f o r M-  for  had  small  immediately  T h i s movement was d e n s i t y - d e p e n d e n t  Myers and K r e b s  authors  on  and Hebb  area  either  a periodicity  (1968) r e p o r t e d t h a t  depopulated  two  animals  of  mammals c o n t i n u o u s l y from  dependent Calhoun  species  colonized  D e s e r t and f o u n d  species.  Van  were  the resident  removed  Sonoran  with other  onto  the  o f d e e r m i c e and on  the  control  (see T a b l e 2.3) When  my  removal  (poison baiting)  those  reported i n the l i t e r a t u r e ,  experiments  a r e compared  t h e r e have been v e r y  few  69 studies deer  which  have  mice on t h e b a i t e d  concluded  that data  information  on  little  invasion  both  area  seed  of  determining controlled.,  shortly  conclusion  et  effect  and s t r e s s e d  baits  are  that  study.  area  mammals^  a  censusing  baiting  Yeatman  Hoffer  et  poisons. colonize  in  these  because  of  the  (1960),  properly  Hooven  repopulation  of that  (1953,  poisoned rebaiting  (1970) a l s o came  to  this  I n g e n e r a l , t h e few f o l l o w - u p  censuses  very  that  on c o n i f e r  rodents  s h o r t time  seed  of  poisoned  are  only  absent  from  as e v i d e n c e d of  a  i n my  poison  baits  r e d u c t i o n i n t h e numbers o f s m a l l  a l . (1969) came t o a s i m i l a r c o n c l u s i o n i n  regions  poison on  baiting. smaller  areas  (1.1  (>20 ha) which have been b a i t e d  ha) with  t h e r e i s a much g r e a t e r a r e a f o r mice t o  large-scale rapid  not  for  f o r more i n t e n s i v e s a m p l i n g  were c o n d u c t e d  Conseguently,  successful  i f  r e p o r t o f mice s u r v i v i n g  most c l e a r c u t  was  methods  was  and s u g g e s t e d  effect  f c r any permanent  My e x p e r i m e n t s than  their  reported  Therefore, the continual reapplication  necessary  their  for  period-  (1955)  Cochran  have been done c o n c l u d e d  poisoned  is  be used.  mice b u t t h e r e  restricted  t h e need  p o p u l a t i o n s and t h e i r  presented  on a p e n i n s u l a w h i c h  baiting  rodent  not present  addition,  (1969) r e p o r t e d after  did (1950b)  and d e e r  poison  was n e c e s s a r y .  to  but  (1940)  In  but  (1958),  and d e n s i t y o f  Schopmeyer  Orr-Ewing  al.  of  McGregor  several times  successful  located  Allen  1955a) and G a s h w i l e r clearcuts  survival  areas-  survival  clearcuts,  the  seed  for the pre-baiting  was  by m i c e .  stocking  was  f o r deer mice-  data a v a i l a b l e  baiting  both  and c o n t r o l  baiting  quantitative  the  measured  poisoning  programs.  r a t e a t w h i c h mice c o l o n i z e d my  However, removal  70 areas,  and  conclude better  its  inability  that  seed  than that  s u r v i v a l on  obtained  o r r e p e l l e n t was  Since  Finnis  concluded  an  approach of  that  the  mice f r o m e a t i n g abrupt reduction  (1S57) r e p o r t e d exposure  variance  that  to  with  by  remove r o d e n t  populations  al.  reduction  invasion  Matschke  poisoning reinvasion species.  and  1080  endrin,  must be Passcf  poison  new  the  new  developed.  However, he  a  result was  the  at  early  fluoracetate) failed  above  (1S7G)  However,  similar  to  chemicals  not  hazardous  for  and  there  poisoned  that  the  use  hazard of  Marsh  et  complete the  areas.  Fank  from  their  to to  control  non-target  rodenticides  baits the  reducing  still  methods  the  anticoagulant discuss  was  conclusion  as w e l l as  d i d not  the  b a i t s which r e s u l t e d i n  emphasized  (1974) r e v i e w e d  and  Thus,  more v e c t o r s  mice o n t o t h e a  evaluated  California  Lawrence  result  r e p e l l e n t which was  animals.  and  resulted  as  (sodium  on  Howard e t a l .  (1972) came t o program  1956,  effective in  which s i m i l a r l y  produced s e v e r a l  of  This  findings.  Spencer  completely.  mice.  resident  by  (1955b,  f i r seed  seed.  or  of  that  avoid  poison  inevitable and  not  need f o r a  on  discussed  However, D i c k and  restrictions  (1974) r e p o r t e d  carry  endrin  years,  of deer  c o n i f e r seed  Hooven  s e e d and  ten  populations  little  treated  strychnine  I  be  was  t e t r a m i n e and  to non-target species  would  r e p e l l e n t , tetramine,  reported  were r e p l a c e d  the  as  first and  tetramine-coated  such  past  (1955)  rodents did  rodenticides  In the  h a v i n g the  i n numbers.  previously  poison,  study.  rcdenticide  stopping  and  in this  own  then,  with  large clearcuts  more l o g i c a l  1957)  of  t o remove a l l a n i m a l s  The  (1954).  in  the  that  problem  in  had  been  of  their  71 failure  t o remove a l l mice from a  discussed  the  merits  (chlcrophacinone mammals. toxic  He  and  to b l a c k b i r d s , as  target  species  in  the  to predator  owls  that  animals  disappeared  into  for this  p o o r l y known.  statement,  poisoning or  and  (rain  the  snow)  from  their  is  that deer  of  this  i s attempted  associated  making  study  on  aversive  mouse c o n t r o l  shorter  t h a n 8 months.  are  to c o n t r o l  should  obvious invasion  when of  the  mice.  animals  (as i n d i c a t e d  d e s t r o y 50,000 D o u g l a s  t o d e s t r o y most o f t h e c o n i f e r It  in  efficacy  days.  management  could  problems  very  mice f o r more t h a n a few  The  Very few  causes  bait  the same p o i s o n a t i n t e r v a l s  a r e a by  Evidence  the  employ  treated  which  is  natural  not  bait  death,  of  o f mice t o t o x i c a n t s  of  affected  of small  conditioning  implications  (1975)  i n g e n e r a l , the f a t e  and  (1977) c o n c l u d e d  reapplication  before  to predators.  indicate  a c c e p t a b l e to deer  Howard e t a l .  Hooven  (1977) f u r t h e r d i s c u s s t h e  c h e m i c a l s and  i n c l e m e n t weather  available  and  that  p o i s o n i n g when  i n nature because  burrows  non-  concluded  Secondly,  reduced  slightly  toxic for  secondary  of the poison  Marsh e t a l .  t h e a b o v e two  with  weasels.  forest  g u e s t i o n i s then  report  caused  poisons  only  of s l i g h t l y  This  their  availability  mammals which d i e o f  of  and  The  (1975)  of s m a l l  was  pheasants.  mice  t h i s h a z a r d was  the  lacking  and  Hcoven  anticoagulant  chlorophacinone  wild?  deer  area.  for control  t o what i s t h e d e f i n i t i o n  stated  is  new  diphacinone)  ducks,  diaphacinone-killed  reduced  two  reported that  raised  fed  of  poisoned  impossible  to  in  f i r seeds seed  Figure i n 15  3.5,  5  mice/ha  days) a r e  required  d i s p e r s e d over  remove a l l a n i m a l s , and  a  clearcut.  yet f o r the  past  72 forty very  years, poison b a i t i n g little  h a s been c o n t i n u a l l y  attempted,  success.  Thus, i n t e n s i v e  study o f seed  deer  mice cn c o n t r o l  and r e m o v a l  has  shown  the f u t i l i t y  survival  (poisoned)  and areas  movements , i n my  o f b a i t i n g owing t o t h e r a p i d  by m i c e a n d c o n s e q u e n t  destruction  also  f o r a new p h i l o s o p h y i n d e a l i n g  shown  the  need  h i s t o r i c a l and c o n t e m p o r a r y seed  supply  control for  with  used  in  o f t h e seed  problem  of  direct-seeding  projects.  technique described i n t h i s t h e s i s  t h i s much-needed new a p p r o a c h  study,  reinvasion  supply.  rodents  of  It  has  with  this  consuming  the  The b i o l o g i c a l  provides  to reforestation.  the  basis  73 Figure grids  2. 1aG,  forest.  and  Map Q.  of study area Grid  Q  was  f o r removal L-shaped  G r i d s G and J were l o c a t e d  experiments  and  located  on t h e c l e a r c u t  area.  showing in  the  74'  Grid Q I  +  1  1  K  1  H—I—»—I—I  +  * 4  \  1  1  -I  r1  -I—I—1 VH  1  f  1  1  1—| II 1—\  1  \  r  \  FOREST  Grid J Removal  N  CLEARCUT Grid G + trap station Scale: 1 cm= 23 m  Figure of  2.1b-  Schematic  mice moving o n t o  poison b a i t s ) ,  grid  the  illustration  removal area  J , from  of the  (e.g.  surrounding  an  predicted area  regions.  response  treated  with  76  77 figure  2.2-  colonizing  Schematic removal g r i d  illustration J during  o f e x p e r i m e n t ft i n t h e f a l l  of  of  the f i r s t  1977-  the two  origin trapping  of  mice  periods  7$  Fall 1977  O r i g i n of mice c o l o n i z i n g removal B Grid J  EXPERIMENT A.  (resident)  A Grid Q  ;  Removal P e r i o d No. 1 . Aug. 21 All  animals  O  removed  O New  'A  A  All  B  animals  removed  Q  m\  o  '  A  ng Ea  o , •'  m  Aug. 23  Aug. 24  O  All  A  S  O  animals  1  o  removed  I  Douglas f i r seed  (0.81 kg/ha)'  % S u r v i v a l of seed  Control  100  Removal  100  A  s e t out on Aug. 24; checked  Aug. 24  animals  removed 1  O  All  12 days l a t e r  (Sept. 5)  '  Sept. 5  Removal P e r i o d No. 2 '  •  Sept. 4  Sept. 5 All  animals  All  A  animals  1  removed  O O  removed  O  o  o  O 1  79 Figure 2 . 3 . colonizing  Schematic removal g r i d  4 of experiment  B.  illustration J during  of  the  the trapping  origin periods  of no.  mice 3 and  80  Fall 1977  O r i g i n o f mice c o l o n i z i n g removal  area:  © G r i d G.. A Grid Q  EXPERIMENT B. Removal P e r i o d  A  •  9  Sept. 19 All  O  A  O New  No. S animals,  All  removed .  animals  removed  ®  O O O  o  O  Sept. 21 O  °  '  O  Douglas  f i r seed  (0.81 kg/ha)  animals  removed  A  °  All  O  O  A  © o A  O O.  s e t out on Sept. 18; checked % S u r v i v a l of seed Sept. 1£  ,  Sept. 21  Control  100  3i.O  Removal  100  5.0  Removal P e r i o d No. 4  Oct. 2  Oct. 3  3 days l a t e r  (Sept. 21)  81 Figure and  2.4.  Population  removal g r i d  experiments.  J during  d e n s i t y on c o n t r o l g r i d the f a l l  1977  and  H, s e e d  spring  1S78  grid  I,  seeding  82:  Control Grid H  Removal Grid J  Removal  Aug Sep 1977  Removal  Oct  Mar 1978  Apr  83 Figure  2.5.  colonizing  Schematic  removal g r i d  illustration J during  of experiment C i n s p r i n g  1978.  of  the f i r s t  the two  origin trapping  of  mice  periods  84  Spring 1978  O r i g i n of mice c o l o n i z i n g • Grid J  removal  (resident)  • Grid G EXPERIMENT C. Removal P e r i o d  O No. 1 March 5  •  animals  All  •  removed  •  •  March 6 All  • _  New  animals  removed  • •  •  •  • •  Removal P e r i o d  No. 2 March 19  O  March 20 All  animals  All  removed  Douglas  f i r seed  -  animals  removed  (0.405 kg/ha) s e t out on March 2 ; checked % S u r v i v a l of seed March 20  April 1  Control  100.0  0.0  Removal  100.0  8.0  12 days l a t e r  (April  1)  85  Figure  2.6.  colonizing  Schematic  removal g r i d  4 of experiment  D.  illustration J during  of  the  the t r a p p i n g  origin  periods  no.  of  mice 3 and  Spring 1978  86 O r i g i n of mice c o l o n i z i n g  removal  • Grid G A Grid Q  EXPERIMENT D.  O  Removal P e r i o d No. 3 April 2  New April  All  O  animals  3  , All  removed  animals  removed  O  — n r i LU A  A  All  O  animals  removed •  , All  removed  A  A  animals  O A  A  •  O O  Douglas  f i r seed  (0.405 kg/ha) s e t out on A p r i l  2; checked' 5 days l a t e r  % S u r v i v a l o f seed A  P il r  April 7  2  Control  100.0  10.0  Removal  100.0  7.4  Removal P e r i o d  No. 4 April  16  o  A  April  •  A  . A  17  o  &  o  •  •  A  * A  O  A A  o A  (April  7)  87 Table 2.1. Trappability estimates for Peromyscus maniculatus on the control and experimental areas. Sample size i n parentheses. Maximum trappability i s the proportion of those known to be alive that are actually caught i n a trapping session. Minimum unweighted trappability estimates f i r s t and last captures and provides only one value for each individual regardless of how long i t lives.  Control  Seed experimental  Grid H  Grid I >  Males  Females  Males  Females  F a l l 1977 Maximum trappability  0.72 (30)  0.79 (20)  0.73 (34)  0.76 (28)  0.71 (26)  0.75 (17)  0.66 (29)  0.66 (22)  0.88 (14)  0.61 (10)  0.81 (23)  0.71 (19)  0.74 (9)  0.39 (6)  0.71 (16)  0.54 (13)  Minimum unweighted trappability Sprint 1978 Maximum trappability Minimum unweighted trappability  Table 2.2.  Comparison of s u r v i v a l of Douglas f i r seed on control and removal  g r i d s . The number of animals removed and number of seeds surviving on removal areas are compared with control areas which were seeded i n an i d e n t i a l manner but d i d not have the resident population of mice removed. The experiment was conducted f o r s i x weeks (August 14 - September 25, 1975). I n i t i a l seeding density was 3.24 kg/ha.  . Forest Control  Clearcut Removal  Control  Removal  Number of animals captured during  16*  61  23*  34  13.0  9.0  4.7  3.6  experiment  Percentage o f Douglas-fir seed surviving  * average of 4 trapping periods  Table 2.3.  Number of Oregon voles, shrews, and red-backed voles captured  on control grid H and experimental seed grid I and number of these animals removed from grid J. The values for grids H and I are the averages, and for grid J are the total numbers, for the four trapping periods during each of the f a l l and spring experiments.  Control  Seed experimental  Grid H  Removal  Grid I  Grid J  Vole. Shrew RBV  Vole  Shrew RBV  Vole  Shrew RBV  2.5  2.5  0  2.0  1.0  0  1.0  2.0  1.5  F a l l 1977  5.8  3.5  0  3.0  6.0  0  20  18  8  Spring 1978  3.3  3.0  0  3.0  0.8  0  22  8  3  Pre-removal  a  a  Average of 2 trapping periods prior to f a l l removal experiments  vole (Oregon vole) RBV  (Red-backed vole)  90  CHAPTER  3  THE USE OF ALTERNATIVE FOODS TO  CONIFER  REDUCE  SEED PREDATION BY DEER  MICE  INTRODUCTION Biological attempt  to  control  reduce  the a c t i o n s o f biological any  has been  the average d e n s i t y  predators,  control  traditionally  may a l s o  parasites, refer  agent  alternative This  or  diseases-  For  along  by Howard birds,  successful  1960)  (Howard  1967).  or  F o r mammals,  1962).  have  with  to a s i t u a t i o n  Using  where, w i t h o u t  or e l i m i n a t e d  preferred  (buffer)  often  habitat  manipulation  by a or  control.  have  been  has been  fairly  (1967).  providing  i n diverting  (Hagar  trees  process-  an  However,  f o o d s may t h u s be c o n s i d e r e d as b i o l o g i c a l  approach  discussed  or  as  o f a p e s t p o p u l a t i o n by  change i n p e s t numbers, damage i s r e d u c e d  biological  defined  alternative  j u n c o s from  in luring  The a v a i l a b i l i t y  f i r seed  around  damage from  of a l t e r n a t i v e  browse may r e d u c e b r o w s i n g  on a  w a t e r f o w l away f r o m  prunings p i l e d minimized  foods  of  conifer  the  cutover  area  vegetable crops  base  of  orchard  meadow v o l e s  (Fitzwater  and p r e f e r r e d  species of  seedlings  by  sncwshoe  91  hares  (Badwan  and  Campbell  1968).  By p r o v i d i n g  f o o d s , v a r i o u s a u t h o r s have a t t e m p t e d (Boy  1960;  1974;  and  Baron  et a l .  Campbell  and  Evans  Seed p r e d a t i o n by and  o t h e r r o d e n t s has  cutover forest et  al.  less  p r e d a t i o n may preferred  Similarly, take  one  as r e a d i l y  projects seed  mouse  contributed  (Peromyscus  to the  to  be  deer  reduced  by  the  or  more  mice. by  deer  Berry  inhabiting  range  and  land,  been  but  no  upper  limits  per  mouse  with  Douglas  reduced  of densities  be d e t e r m i n e d ,  f i r seeds  p r e d a t i o n on  then  these tree  mice p r e f e r  or  reforestation Some work  on  (Everett et a l .  1978)  been done on  by d i r e c t the  deer  conditions for seeding.  responses of  number  t h e use  seeds.  foods.  birds  of Douglas  (or o t h e r c o n i f e r  are  granivorcus  under f i e l d  f o r the number o f mice and can  seed.  r e s e a r c h has  designed t o determine  a wide r a n g e  in  for  mice  reforestation  to  that  used  done  the purpose  mice  Everett  indigenous  the t r e e  f o r deer  lands.  s e e d s p e c i e s which  than  consumption  T h i s s t u d y was  i n regenerating  that  c o u l d be on  maniculatus)  These a u t h o r s b e l i e v e  mouse s e e d p r e f e r e n c e and of successful  Campbell  food  planting  predation  1976)  1967;  the  a l t e r n a t i v e foods  p r e f e r e n c e has r e c e n t l y  ( G c e b e l and  browsing  of understanding  mouse  as c o n i f e r s e e d  lessen  failure  w e l l as o v e r g r a z e d range  preferences of  deer  1975).  the deer  l a n d s as  reduce  Dasmann e t a l .  (1978) d i s c u s s t h e a d v a n t a g e s  h a b i t s and seed  1966;  to  alternative  f i r seed. of  seeds  of a l t e r n a t i v e  seeds)  deer If  the  taken foods  should r e s u l t i n  92  MATERIALS From March (1.1  May  to ha)  to  September  November  1977,  in forest  study  areas  with  Longworth  clearcut  (G, H,  grids  checkerboard  1975,  one  (A, B,  1)  grid,  49  live-trap  was  baited  b a t t i n g was checked  with  E,  and  F)  November  five  and  at the  forest  trapped  stations tape  and  w i t h i n a 2-m  every  weeks  two  ( P ) , and On  l o c a t e d at  3, a n d  each 15.2-m One  r a d i u s of each s t a t i o n .  Traps  two  ( F i g u r e 1.4).  p e a n u t b u t t e r , P u r i n a l a b chow, and  d a y s 2 and  grids Slash  1977.  were  and  Burn and  grid  in  string  1976,  experimental  were l i v e - t r a p p e d  s u p p l i e d as bedding.  on  to  Another  trap  marked by f l a g g i n g placed  April  were a l s o  intervals  were  D,  live-traps. N)  METHODS  control  C,  I , J , R,  (M and  AND  were  set  Traps  Terylene  on  day  1,  t h e n l o c k e d open between t r a p p i n g  periods. All  deer  mice  balances,  sexed,  fingerling  fish  palpating openings  and  The animals  male  and tags.  Breeding  testes  and  sufficiently  weighed  Hilborn model  et  accurate  al.  spring  serially-numbered  performance  was  noted  by  females.  at  minimum number o f  consecutive  have  enumeration  are  i s the  each  (1976)  estimates  o r more o f t h e a n i m a l s  Pesola  o b s e r v i n g the c o n d i t i o n of v a g i n a l  (MNA)  that  cn  with  value f o r population s i z e  known t o be a l i v e  simulation  were  ear-tagged  mamillaries o f t h e  best  interval.  80%  captured  demonstrated techniques  f o r a trapping design  caught  two-week  at each  sampling  by  a  provide i n which time.  93  Douglas  f i r seed p o p u l a t i e n s  Each divided plot,  experimental grid,  into  36  a 0.61  for  seed s a m p l i n g  the  responses  each  of  seed  of  grid  seeds then  seeds. seed  seed  the  first  The r e s t  guadrat  was  (0.093  sg  m)  of the a l l o t t e d  for  then conducted  2500  a  given  units seed  in  a  throw  more  filtered The trial  later  collected analysis.  o u t by i n s p e c t i o n next  three  a t two-week  than from Whole  chosen  i n a l l r e s p e c t s except  that  of  seed-sampling  plot.  into  the  i n t e r v a l s f o r the  each and  were 25  (0.093  sg  f o r sampling  once  and u s i n g d i f f e r e n t  experiments  I  dispersal.  No q u a d r a t  were  density  seed  week.  more  f i r  figure,  o f the a r e a of that  were r a n d o m l y  was sampled  (area  was t h e n s p r e a d by hand  quadrat  each  packaged  Douglas  Using t h i s  in  for  two  I p l a c e d a known d e n s i t y o f  over the r e s t  seed  and  meter o f g r i d  of  22.35 g.  experiment,  during this  was  weighed  units  packaged  area  i n 1975 and one t r i a l i n  T w e l v e q u a d r a t s and one o f f o u r  samples  suitable  f i r seeds,  n e x t s i x weeks.  Litter  In each  F o r measurement o f  Douglas  S e v e r a l samples  and a v e r a g e d  of four  Sampling  in a  per square  was t a k e n n o t t o a c c i d e n t a l l y  sampling  systematically  ns) p l o t s .  1.4).  to  desired  s q m).  as u n i f o r m l y as p o s s i b l e Care  mice  many g o f s e e d s t o u s e  For  guadrat.  was l o c a t e d (Figure  experiment,  weighed  i n each  231 s q u a r e  were c o n d u c t e d  t h e amount  knew how  was  1977.  = 8,361.3 were  deer  trials  B e f o r e each to  m quadrat  and r e c o v e r y  o f 1976 and  according  m x 91.2 m,  (15.2 m x 15.2 m =  m x 0.61  experimental  91.2  in  this  sampling eaten sized  identical quadrats  m) each  trial. u n i t and  seeds  were  screens. t o the  were  first  randomly  94 chosen  for  each  0.093 sg m u n i t were  placed  densities which  of  was  m a r k e d by  seed  no  Whole  0.5  means,  seed  week  seeds  standard  trials  are  experimental g u a d r a t on  seed-sampling  any  ether potential on  from  adjacent  o r more s e e d s  each  in  left  in  place.  Egual  m  units,  Douglas f i r  and  35%  3.1.  In  c o v e r was  propped  predators  the g r i d s a t l e a s t  one  The  free  up  the  rate  confidence limits  Appendix  but were  of  predation  f o r the  the  from  of  rate.  fourth  placed ever  These c o v e r s prevented r a i n  seed  sg  in a  markers  seed.  0.CS3  was ray m e a s u r e o f  errors,  areas  These  Remains of eaten  (1977), a p l a s t i c  a grid.  one  for eventual identification  were  listed  trial  the  placed  cm  marked s e e d s .  disappearance of these seeds The  of the  wooden t o o t h p i c k s .  were p l a c e d i n  were removed e a c h  predator.  location  approximately  contained  seeds  grid.  each  disturbing  to a l l o w  access.  mice  They  week b e f o r e t h e s e e d  and were  experiment  began. I grid  placed to  measure  experiments. a  frame  box  mesh) c o v e r e d which  one  seed-fall potential  These  traps  (2.5-cm x the base  allowed seeds  trap  i n a central  natural  w e r e 0.37  position  seed-fall  during  sg m i n a r e a and  7.5-cm s i d e s ) . 1 cm  mesh h a r d w a r e  to f a l l  into  the  cloth  each these  composed  Window s c r e e n  with  on  (14  on  by  the  of 18  top,  trap.  Predation  deer of  General  information  mice  Douglas  on  about  the  direct  f i r seeds  has  been o b t a i n e d from  the remains o f eaten seeds  from  and  analysis  mice  t r a p p e d i n a r e a s w i t h two  Two  0.42-ha  snap-trap grids  effect  of  different (S-1 and  of p r e d a t i o n  stomach seed  by  collection contents  densities.  S-2) , l o c a t e d  i n the  95  forest,  had 30 t r a p  flagging butter set  tape  day  These g r i d s of  and s t r i n g .  were p l a c e d  on  1  i n a 2-m  and  grids)  During  at  15.2-m  intervals  r a d i u s o f each s t a t i o n .  ( i n an i d e n t i c a l  following  One month l a t e r ,  litter  samples  estimation  manner t o  week, A u g u s t  were l o c a t e d  a l l mice were f r o z e n collected  number  were  the  seeding  from  14, were  analyses. grids  were  again  for later  autopsy.  Nine  sampling  guadrats  for  time.  These  quadrats  232.3 s q m p l o t s and were i d e n t i c a l i n  t o t h o s e on l i v e - t r a p  grids.  One  (0.093  sq  m)  was r a n d o m l y c h o s e n f o r s a m p l i n g i n e a c h g u a d r a t . The  stomach Seed  number  of  was r e c o r d e d  Douglas f i r f o r a l l mice  i n t e g u m e n t s were i d e n t i f i e d  seed integuments found i n each captured  Badioactively-tagged In  August  established trap  Longworth peanut  1976,  butter  These  grids  1976,  and  two  and  0.10-ha  and c l e a r c u t  (3x3)  live-traps  snap-trap  located  on D o u g l a s f i r s e e d s .  at  grids  (B-C  habitats. 15.2-m  and  fi-F)  Each g r i d intervals  p e r s t a t i o n . _ The t r a p s  were  were  had  cine  with  two  baited  with  P u r i n a l a b chow and had c o t t o n f o r b e d d i n g .  were f i r s t  t r a p p e d on t h e n i g h t s  of  August  a l l s m a l l mammals were removed e x c e p t f o r d e e r  were e a r - t a g g e d  grids-  seed  in forest  stations  on  by c o m p a r i s o n w i t h t h e stomach  c o n t e n t s o f a l a b mouse f e d e x c l u s i v e l y  which  Traps  19-21, a l l mice  both  o f seeds/ha at t h i s  in alternate  configuration unit  September 19-21,  were  of  peanut  on d a y s 2 and 3 and t h e n removed.  removed and f r o z e n f o r s u b s e g u e n t stomach  and  with  by  w i t h 540,000 D o u g l a s f i r s e e d s on August  the  snap-trapped  marked  Three s n a p - t r a p s b a i t e d  checked  were s e e d e d  live-trap  1975.  stations  with  serially-numbered  fingerling  22-23, mice, fish  96 tagsseed  Badioactively-tagged (20,000 seeds)  August  27-  The  O c t o b e r 4-5  seed  (ca.  were d i s p e r s e d  grids  to record  400)  and  uniformly  on  normal  untagged  each  grid  on  were t h e n t r a p p e d a g a i n on t h e n i g h t s  t h e number o f d e e r mice  present  of  following  the r a d i o a c t i v e seeding. The Douglas two  laboratory f i r seed  was  as  were  ready  for dispersing  Buried easily  dried  detected  The  into  with  a  tagging  milliCuries  cf  Scandium-46.  a fume hood  f o r 24 h o u r s and  the  with  field  crystal  crystal  scintillation  the  were t h e n  untagged  counter  c o u n t e r w i t h an a u d i o  forest  grid  radioactive  the r a t i o  on  would  15.  distributed  determine  I t was  be i n c l u d e d  o f tagged t o untagged  were u n i f o r m l y  about  a r e a on September 9  September  seed  in a strip  s e e d s was  over the g r i d  whether  a p p r o x i m a t e l y 800  s e e d s t o two  All  s e e d s were consumed a f t e r  five  probe.  transmitter 20 m wide  on  around  that at  least  large caches  since  1:50,  and  all  seeds  area.  d e e r mice days  be  (Thyac  again  assumed  the tagged seeds  fed  and  i n any  seed.  meter, c o u l d  scintillation  t o f i n d c a c h e s of seeds  the  c l e a n s e e d s were s o a k e d f o r  I I I model) e q u i p p e d w i t h a gamma s c i n t i l l a t i o n  used  To  10  radioactively  s e e d s down t o a d e p t h o f one  the o u t s i d e o f each g r i d  one  f o l l o w s : 800  under  individual  Victoreen  the  for  h o u r s i n 15 ml 0.5fl B C l and  They  was  procedure  were d i s t a s t e f u l , i n the  w i t h no  I  laboratory.  apparent harmful  e f f e c t s t o the a n i m a l s . Invertebrate During exclosures and  populations September  were l o c a t e d  Slash study areas.  and  October  in the forest The  1977,  five  rodent-proof  and a t e a c h  of  e x c l o s u r e s were 0.37  sq.  the  Burn  m i n area  97  and  15 cm  in  hardware ground. area, seed  height.  cloth  They  which,  on  but was  rodents  marked  by  of the 4  a  with  0.8-cm  extended  to  seeding  reforestation  programs.  e v e r y two  the  trials  laboratory  Survival  5 cm  of  the  of  the  Douglas f i r  units  with  density  of seeds  densities  used  similar seeds  to that  was  then  its (0.81  in  my  used  in  checked  period.  1977  of  Douglas  was  determined i n a n a t u r a l  and  f i r seeds e a t e n and/or  C e n t e r , D.B.C.  Two  seed-sampling  quadrats  m)  allotted  seed  taken  t o p u t more s e e d  survival  units i n  (0-37  a  male  mice  were t e s t e d  at least  room-  Water and  l a b chow were a l w a y s  when o n l y water  Alternative  food seed  k e r n e l s were weighed  were  the  mice Care  m i n area.  established.  o r mere -of the rest  of  four the  t h e room, c a r e b e i n g the  sampling  areas.  later-  o n l y once f o r a 2 4 - h o u r  2 days a d a p t a t i o n t o  experiment,  number  deer  sg  r e c o r d e d 24 h o u r s  following  samples  18.6  then  by a c c i d e n t on then  the  at the Animal  was  s p r e a d u n i f o r m l y around  period  Several  room  p l a c e d i n one and  1978,  by i n d i v i d u a l  sq m i n area)  quadrat  o f t h e s e e d s was  Individual  taken  environment  d e n s i t y o f s e e d s was  was  March t o May  rooms were u s e d , e a c h  (0.0S3 s q  not  was  m)  into  out  One  mesh  studies  From H a y ; t o November  known  This  lowest and  weeks o v e r a 4-week  excluded.  (0.093 s g  toothpick.  equivalent  experimental  The  sides,  were e f f e c t i v e l y  placed i n each  kg/ha) was  A  the  covered  I n v e r t e b r a t e s were t h u s a b l e t o move i n and  location  Ten  were  available  was  available.  10 00  sunflower  the  environment  except  d u r i n g an  trials of with  seeds  and  t h e mean v a l u e r e p r e s e n t i n g  100 0 o a t that  given  98  number o f s e e d s . the number grid.  T h i s v a l u e was u s e d  of seeds  These  seeds,  were d i s t r i b u t e d manner  Douglas with  to  previously.  f i r were  2 alternative  were c o n d u c t e d  sunflower  to Douglas  November  surviving  surviving  fir).  doubled  the  f i r clearcut In  0.63  appeared  experiments  was  number  was and  the  sampling  adequate  and t a k e n o r e a t e n  for  experiments seeds The  and  ratios The  o f 3:3:2  alternative  food  and seed  were done i n 1977.  w i t h 25 g u a d r a t s of quadrats  i n experiments  for  (50  on a 7:1  in  August  both  sampling  schemes  of sunflower  I n November, t h e p r o p o r t i o n (n=100 SE=0.05)  proportion  (n=100 SE=0.07) the  a  t h e p r o p o r t i o n of Douglas f i r  0.09  0.65  a  in  (control).  n=50 SE=0.04), and t h e p r o p o r t i o n  SE=0.07), was  0:1  Three  grid  August, was  f i r surviving  surviving  and  f o o d s were i n r a t i o s  was i d e n t i c a l a t 0.0.  (n=50  surviving  I  2 weeks  SE=0.04;  Thus, i t  grids  f i r seed  i n 1S76 and f o u r t r i a l s  1977.  after  7:1  t h e adequacy o f s a m p l i n g  units),  Douglas  experimental  (control).  of  ratios  on  with Douglas f i r ,  f i r were 7:1, 5:1,: 3:1, and 0: 1  sampling  (n=100  the  determine  plots  sunflower  To d e t e r m i n e  0.56  The  36  combinations  i n t h e Douglas  (sunflower:oats:Douglas  trials  the  with  combination  and  on  that  o a t s and D o u g l a s  5:2:1  f o r each o f  i n various  and marked  identical  described  by w e i g h t  as a m u l t i p l e t o  of  v e r s u s 0.54  scheme  used  compared  sunflower  of with seed  (n=50 SE=0.09). in  these  seed  d e t e r m i n i n g t h e amounts o f s e e d  by d e e r  mice.  99  RESULTS The seed  d a t a composing  density,  the responses  presented  grids.  Identical  grids.  However,  owing  to  seed  e a t i n g b i r d s such these for  open  and  and  mice  with  respect  areas  is  forest  mammal  species  densities  at  Douglas  are equally  in  forest  clearcut on  logged  open  areas  p r e d a t i o n by  and  song  sparrow  to s u c c e s s f u l l y mice.  seed-  The  f i r seeds of  sample  forest  grids  predation  behaviour  colonizing  the r e s u l t s  applicable  to  deer differ logged  o b t a i n e d from  the  areas.  s t u d y o f d e e r mouse-seed r e s p o n s e s  without  as  other shrews  qapperi, Microtus times  and  predators. (Sorex  oregOni)  neither  to  by  given  of  i s unlikely  mice  in  clearcut  such  a l l  the  r e s p o n s e s of deer mice t o the  i n t e r a c t i o n s from  IClethriononmys  deer  varying  the  r e s i d e n c e or seed  the f o r e s t ) ,  allowed  complicating  by  (the s o u r c e r e g i o n  f o r e s t experiments The  junco  Since the foraging  to  obviously  located  in a failure  observed  o f seed d e n s i t i e s .  on  Consequently,  consumption  provided r e l i a b l e  between h a b i t a t s  conducted  q u a d r a t s were  areas, resulted  range  to  to the nature of the t e r r a i n  recovery.  were u n a f f e c t e d by any birds  were  as t h e d a r k - e y e d  measure s e e d  mice  t h i s c h a p t e r , a r e from  experiments  areas, the seed-sampling favourable  in  of deer  group  Other  small  and  voles  spp.) were  at  very  i s primarily  a  low seed  eater. Trappability The  enumeration  of deer  populations  is  based  individuals  in  a  trappability  has  on  given been  mice the  in  assumption  population defined  experimental  by  are Krebs  that  and most  captured. et  al.  control of  the  Maximum (1976)  as  100  follows: trappability^ No.  a c t u a l l y caught  time  method  upwards  the  last  This  trappability is a less  c a p t u r e s and  estimate  individual  fee  present  at  these  expected,  for  periods  unweighted  general,  minimum 1976-77  population  also  i t  with  long  capture  prevalent  was  areas  and  lower  between t h e s e x e s  to the animals  not  bias  P.  densities, lower  trappability,  its  so  is  of  i n Table  3.1.  trappability  except  the  control  comparable  to  I n some i n s t a n c e s , t h e r e  was  which  e n t e r i n g the t r a p s because of  sexes  densities effect  higher densities  of  In  80%  f o r a given experiment,  both  as than  above 70%.  1977,  of the  higher  above In  not  Both  each  was  was  tsice.  v a l u e f o r each  usually  However, i n t h e  with  a t the  E,  animals.  Douglas f i r seeds p r o v i d e d .  affecting  and  B,  variation  mice on  presented  on  slightly  once c r  histories.  during  trappability  to t h e h i g h e r seed  to  unweighted  and  trappability  trappability  large  lives  populations  maximum  c f the e x p e r i m e n t a l  due  long  grids  only  p r o v i d e s o n l y one  i n 1975-77 a r e  that  be  a l l mice caught  unweighted  had  Minimum  how  the  i n most c a s e s  minimum  duricg  hence,  animals  estimates  experimental  estimate.  of t r a p p a b i l i t y  by  t h e r e f o r e , tends  biased estimate since i t e l i m i n a t e s f i r s t  r e g a r d l e s s of  influenced  than  known t o  i n c l u d e s a l l c a p t u r e s and  trappability  may  i / No.  I  This  and  at time  p o p u l a t i o n s exposed  were  more  of seeds.  should seed.  the  have  trappable  If food been  were most  101  E x p e r i m e n t a l s e e d i n g with Douglas Seed  consumption Inspection  over  time  o f stomach c o n t e n t s and t h e c o n s u m p t i o n  on  evidence that seeding.  the the  Table  stomach on g r i d trap  grids,  was 50.1.  experimental  deer 3.2  mouse  S-1 o v e r t i m e .  contained  stomachs)  integuments  of Douglas  of seeds  much l o w e r  and  deer that  seed seed  from  after  seed  density  m i c e were i n d e e d  per f u l l  from each that  stomach  of the f u l l  78.5% (11 endosperm  One month l a t e r , t h e as high  S-1.  taking  These  Mice  on t h e g r i d  as  of and  average  (63.5) as t h a t a t  and e a t i n g  on t h e g r i d .  that d i s t r i b u t e d  o f seeds per  s e e d i n g t h e snap-  exclusively  was s t i l l  on g r i d  after  results  indicate  Douglas  f i r seeds  weeks a f t e r  were p r o b a b l y well  as  the  eating  that  from  t h e p r e v i o u s month a t t h i s v e r y h i g h d e n s i t y o f  seed. cumulative  densities  experiment  number  during  in  o f seed consumption  two  weeks  exception  after  the  six  weeks  a  and f o u r t h  both  o f seeds  continued weeks.  in  per hectare a t four  after  each  i n F i g u r e 3.1.  at a l l densities  seeding  was t h e number  showed  o f seeds taken  1975 a r e i l l u s t r a t e d  rate  third  number  S-2 i n d i c a t e d  almost  direct  f i r seeds  t h e y c o n t i n u e d t o do so more t h a n f o u r  The  which  grid  p e r stomach  c a c h e s made o v e r  seed  mean  One week  f i rseeds.  had been d i s p e r s e d  conifer  the  o f seeds  provided  Douglas  In a d d i t i o n , s e v e r a l subsamples  14  that  grids  t h e mean number o f s e e d i n t e g u m e n t s  mice f r o m  number  seed  eats  presents  stomachs of deer  a  f i r seed  The h i g h e s t  was d u r i n g  experiments.  taken  in  the  the  sample  the  first  An a p p a r e n t first  high r a t e o f consumption However,  seeding  at  trial,  during the this  time  102 probably  gave  an  o v e r e s t i m a t e , s i n c e t h e c u m u l a t i v e number o f  seeds taken decreased at the f i n a l the t o t a l  sampling period.  did  not exhaust  six  seeks o f each e x p e r i m e n t a l t r i a l .  density  cf  seed  This  was  particularly  no.  1  and  pattern  below  the  weeks f o l l o w i n g trials  in  different litter  produced second  at the  densities  identical  Figure  3.1  s a m p l i n g t e c h n i q u e s gave from  in  consumption was  25  also  similar  for  no.  in  be  in  no.  2.  The two  seeding  that  the  two  results. 1 and  the  The  the  second  seeds trial,  were a l m o s t i d e n t i c a l .  use  in  the  a  trial  the f i r s t  indicates  very  which  during  the  predation.  i n a l l subseguent  guadrats  curves adopted  to  density  in trial  12 g u a d r a t s i n t r i a l  toothpicks  during  appeared  lowest  r a t e of seed consumption  1976-77.  method  There  grid  t h e mice r e d u c e d t h e i r  lowest  s e e d i n g was  samples  marked by  which  evident  two  of highest  number o f s e e d s on any  Consumption  remaining  The seed  e x p e r i m e n t s i n 1976-77. Badioactively-tagged The  results  seed  from  the  dispersal  s e e d s a r e shown i n T a b l e 3.3.  of  radioactively-tagged  In t h e f o r e s t ,  where s e e d s o r s e e d f r a g m e n t s were f o u n d had (radioactive), one  the c l e a r c u t ,  whole s e e d ; t h e o t h e r 7 had  These deer of  w h e r e a s on  fragmented mice  a  (Lawrence  number  Hadiation  on  of  and l e d i s k e seeds  were  t h e g r i d s came f r o m  seeds p r e s e n t from t h e o r i g i n a l the  forest  had  17  o n l y one  2 of 9 caches  the remains  s e e d s were o p e n e d  1U o f  locations whole s e e d had  o f up t o f i v e  only seeds.  i n a manner c h a r a c t e r i s t i c  1962). recorded whole  No t y p i c a l from on and  distribution.  83 whole s e e d s , which  may  of  rodent caches the g r i d  eaten  area.  radioactive  A s i n g l e cache i n  reflect  the a c t i v i t y  of  103  a Northwestern  chipmunk  (Eutamias  Prior to seeding, a t o t a l the c l e a r c u t seeding, clearcut were  grid  five  mice  (3  recaptures).  period  were  These  British  at the area.  mice was c a p t u r e d on grid.  Following  r e c a p t u r e s ) were c a p t u r e d on t h e  densities  o p e r a t e d i n both  of deer  deer  on t h e f o r e s t  as part o f another  number  of f i v e  and t e n a n i m a l s on t h e f o r e s t  and t h e d e n s i t y  control grids  agio en us) o b s e r v e d  grid  were c o m p a r a b l e  habitats  experiments  mice f o r f o r e s t  was n i n e a n i m a l s  during  t o t h o s e on  the  same  They r e p r e s e n t an  and c l e a r c u t  (5  habitats  time  average  in coastal  Columbia.  Invertebrates To d e t e r m i n e by  t h e e x t e n t o f p r e d a t i o n on D o u g l a s  invertebrates,  proof e x c l o s u r e s . seeds remained Slash  (n=20) o f t h e s e e d  At the Burn,  the  was p r e s e n t a f t e r  both  t h e r e was e v i d e n c e o f s h r e w s  some o f t h e e x c l o s u r e s and e a t i n g s e e d .  each e x p e r i m e n t a l t r i a l , Douglas  f i r seeds  assume t h a t i n v e r t e b r a t e the  at  f o u r weeks.  r e s p o n s e s were measured i n t h e f o r e s t  upon  1976-77 a l t e r n a t i v e  Responses o f deer The  Total alive)  f i r seeds  numbers over  the e f f e c t was  of invertebrates negligible.  food  i n the f o r e s t  of  seeding preying  I shall negligible  also in  experiments. f i r seeds  o f numbers o f d e e r mice  range  was  and/or  S i n c e the  2 weeks a f t e r  p r e d a t i o n on s e e d s  (MUA - minimum a  almost  mice t o D o u g l a s  response  of Douglas  o f seeds i n r o d e n t -  100% (n=20) o f t h e D o u g l a s f i r  2 weeks and 9 5 % a f t e r  study a r e a , 95%  mice e n t e r i n g  in  followed the s u r v i v a l  In the f o r e s t ,  after  2 and 4 weeks.  seed  I  f i r seeds  is illustrated  number seed  to varying  of  animals  densities  i n F i g u r e 3.2. known  to  be  d e n s i t i e s and the c o n t r o l s are  104  shewn.  These  seeding,  results  which  on a l l g r i d s .  in  from  the  first  two  corresponds t o the highest rates There  was  animals a t the f i r s t increase  are  very l i t t l e  four  density  difference  seed d e n s i t i e s .  of  mice  which  weeks of  after  consumption  i n t h e number o f  There  levelled  was  then  an  o f f a t 860,000  seeds/ba. The shown  response  in  Figure  weeks o f e a c h animals The  o f number o f new 3.3.  These  animals t o  data include  seeding experiment*  with  increasing  seed  There density  number o f r e c r u i t s t h e n t e n d e d  d e c l i n e a t the h i g h e r seed limit  to  a r e a even The  the  total  is  p r e s e n t e d i n F i g u r e 3.4  the  first  The  data  densities mice. more  two weeks a f t e r for  the  by  mice  with  with seed  seeds/ha.  In t h e f i e l d ,  1,075,000 range  of  (Figure  on  each  included  response  and t h e n  seeds/ha. seed 3.5)  density  was  started  another  However,  densities similar  perhaps upper  cn a g i v e n  with food. the  forest  3.2) f o r  experimental  grid.  s e e d p r e d a t i o n by unknown as  well  i n the f o r e s t  seed d e n s i t y .  consumption  reached  live  in  the a  as  deer  g i v e s a much seeds  The i n c r e a s e i n  to l e v e l  off  increased  a g a i n a t 860,000  plateau  at  response  simulated  to that  new  seeds/ha.  o f c h a n g e s i n t h e numbers o f  increasing  consumption  seeds/ha  could  o f c h i p m u n k s and s e e d - e a t i n g b i r d s the  in  T h u s , t h e r e was an  p e r mouse p e r day i n  seeding  accurate representation  eaten  two  (raw d a t a g i v e n i n A p p e n d i x  clearcut  Consequently,  only the f i r s t  o f f and e v e n  was s a t u r a t e d  taken  is  up t o 430,000  number o f m i c e t h a t  number o f s e e d s  density  was a n i n c r e a s e  to l e v e l  densities.  when t h e e n v i r o n m e n t  seed  a  at  density  of deer  forest  430,000  of  mice t o a  environment  obtained i n the f i e l d  up t o  105  approximately values seed  was  similar  trials.  seeds/ha  were  One  field or  observed  densities these  floor  mice  on  greater  less  seeds/sq  or  m)  and  i n consumption  of  laboratory at  860,000  of another  seed  (Tamiasciurus douqlasii)  experimental It  advantageous  grids  is  to  forage f o r conifer  of  at about  seeds  which  possible  leave their  seeds  taken and  on  at  a  (8 s e e d s / s g f t o r  had that  normal  the  forest  because  to  107,593  seed  The  lower cost  oats) comprised  the  density  of  m).  The was  alternative  f t or  conifer  foods  seeds  number usually  (1 s e e d / s q  of t h i s  majority of  the  ratios  seeds/ha  deer  attempted  seed  86 s e e d s / s g  of the very high cost  number.of  I then  combined  i n the combined  equal  total  860,000 s e e d s / h a .  experiments  reforestation.  seeds  range  i n these  to the presence  the  i t  The  densities.  f i r seeds  than  for  and  seeds/ha  Douglas  of seeds  squirrels  of  number  seed  due  Douglas  found  the  stabilized  860,GOO  be  some  at these high  alternative  density  t h a n 430,000 s e e d s / h a .  i n trees  Thus,  may  two  squirrels  foraging  at each  (see F i g u r e 3 . 4 ) .  Therefore, the increase  i n the  predator.  of  860,000 s e e d s / h a  in  11  seed  (sunflower  the  seeding  experiments. Experimental The  seeding with  results  sunflower  seed  clearcut  in  forest,  after  Douglas  i n a  uniform 1976  2 weeks, with  30%  and  distribution  alternative  of  in  Douglas the  are presented i n Figure  nearly  60%  of  sunflower) remained  f i r seeds  approximately  f i rseed  experimental seeding with  August  (distributed the  of  Douglas  the  3.6.  with  (distributed  alone) .  after  the  f i r seed  (with  Douglas  f i r  and  forest  Douglas  compared  foods  In  f i r only 4  and the seed  10%  of  weeks,  sunflower)  106 remained, On  but v e r y l i t t l e  the c l e a r c u t ,  after  There  was v i r t u a l l y  forest There  and  survival  clearcut  was g e n e r a l l y  combined  with  illustrated Douglas  In  o f Douglas  sunflower  in  poor  oats  lugust  in  this  f i r seed  when  forest,  declined  of  of  this  a t week 1 o f  sunflower seeds  depleted.  On  the  Douglas  The  food  effect  survival  of  cf  Consequently, Douglas  exhausted  alternative  of  s e e d s and  same  after  period.  4  ever  weeks.  i n week 2 and t h e n food  survival  sources  o f Douglas  a t week  alternative as  After  4,  on  sources a  f i r seed  2 weeks, s u r v i v a l  f i r f o r both seeds  was  food  locations  spread Douglas  Douglas  f i r seed,  further  survival  during the  alternative  different  1976.  control  i s  when  had  f i r was as d i d  sources.  uniformly  September-October  This  was v e r y good  clearcut,  of clumping  o r o a t s i n two  f i r seed  percentage  g r e a t e r t h a n 20% a f t e r 2 weeks b u t d e c l i n e d alternative  f o r the  were p r e f e r e n t i a l l y c h o s e n  nearly  t o 30% a t week 4, when  oats  with both s u n f l o w e r  and on t h e c l e a r c u t  Douglas  and  experiment.  combined  f i r seed  that  at  1976 a r e g i v e n i n F i g u r e 3.7.  survival  Survival  seed  left  time. survived  was l e f t  seed  f i r seed  i n F i g u r e 3.8, w h i c h shows  i n the forest the  o f Douglas  were  the  at this  f i r seeds  seed  no s u n f l o w e r  o a t s and c o n s e q u e n t l y  been  was l e f t  experiment. percentage  oats  a g r e a t e r number  2 weeks, b u t v e r y l i t t l e  time. this  sunflower seed  grid)  (sunflower on  was measured i n was s i a i l a r  the forest  and  to  clearcut.  s h o u l d be s p r e a d u n i f o r m l y  done  the  with  i n the previous experimental  trials. The  results  of experimental seeding with  Douglas  f i r and  107  sunflower November there  seed  a  uniform  1976 a r e i l l u s t r a t e d  distribution  i o Figure  was 50% and 40% r e s p e c t i v e l y  sunflower) itself-  remaining  The  same  distributed  week  4  the  density  t h e second  dropped  sunflower,  control  sunflower on  grid  was  experimental  sequential  grid  seeding  that  did  already  grid.  at this not  o f Douglas  little  Thus,  increase with  (with  f i r by uniformly  f i r seed  at  with s e q u e n t i a l seeding o f  Very  time.  obtained  weeks,  of the experimental  which was t h e same a s t h e d e c l i n e (from  other  2  Douglas  seed  one  Survival  the  After  o f t h e Douglas f i r seed  seeding)  on  cn t h e c l e a r c u t i n  3-9-  with  of  week.  10%  r e m a i n e d on e i t h e r  beyond  compared  (sequential  areas after  on  in  i t  survival  the  50%  to  40%)  sunflower  seed  appeared  that  of Douglas f i r  initial  seeding  of  sunflower. Percentage  survival  s p r i n g seeding experiment Figure fir  3.10.  Survival this  to  be  grids  much  The  1977  with c o n t r o l survival  higher  than  t o be l i t t l e respect  higher  is  survival  Douglas  i t was  on  difference  in  o f Douglas  D o u g l a s f i r by of  in a  itself.  f i r seed  the control.  between t h e  to s e q u e n t i a l seeding  two  a t week 2.  i n weeks 6 and 8 cn t h e g r i d s  with  seeding.  results  forest are clearcut,  with  was s l i g h t l y  second  given  March t o May  seeding,  However, t h e r e a p p e a r e d of  from  compared  After the seguential  sets  seed  At week 2, t h e r e was e x c e l l e n t  with s u n f l o w e r  continued  o f D o u g l a s f i r and s u n f l o w e r  of  presented survival  direct-seeded  this in  of  same Figure  Douglas  with sunflower  experiment  replicated  3.11.  recorded  As  f i r seed  i n the spring.  was  i n the on  the  excellent  when  Seguential  seeding  108  at  week  2 d i d not improve  were s e e d e d  o n l y once w i t h  In  this  summary,  excellent level  forest  grids  duration of the In  mixed on  an attempt  June  conifer  cf  ratios.  gave  the  these  conifer  t o lower  seed,  1  a ratio  two a l t e r n a t i v e  showed late  ratio  poorer fall  November The  f i r seeds  on t h e  control  seeds  control  sunflower  was v e r y  ratio  to  poor  for  t o be  predation  of sunflower  Douglas f i r . on a l l g r i d s a t  to  i n lowering t h e response  Douglas f i r  of deer  mice t o  Douglas  produced  survival  was  overall  seeding  repeated  hoped  f i r beyond  slightly  better  ratio, than  of 5 sunflower  experiment  food sources, I  of  (1976)  a mixture  f i r i n the next  w i t h t h a t f o r t h e 7:1  experiment  are  Douglas  survival  compared  sunflower)  the  o u t an e x p e r i m e n t a l s e e d i n g i n  o f 7:1, I t r i e d  using  5:2:1  at a  seeds.  :  The  i n  throughout  on t h e  successfully  o f 5:1 a n d 3:1  T h u s , t h e 7:1  oats  improve  control  t h e number o f s u n f l o w e r  I carried  best r e s u l t s  Osing  resulted  experiment.  Douglas  these  the  ten times higher than  1977 w i t h r a t i o s  Survival  which  on t h e c l e a r c u t  of Douglas f i r (with  w i t h D o u g l a s f i r and s t i l l  the  t o the g r i d s  experiment  f i r seed  that of  Survival was o v e r  seeding  Douglas  at least f o u r times weeks.  the  of  relative  sunflower.  spring  survival  eight  survival  i n July this  survival  1977.  ratio  that already  2 By  would  obtained.  of Douglas f i r  but a l l experimental  that i n the spring  experiments.  :  Thus,  grids  (1977) o r  this  a t a more a p p r o p r i a t e t i m e  same  of year i n  1977. results  of seeding  shown i n F i g u r e  3.12.  w i t h o a t s and s u n f l o w e r There  was  excellent  i n late survival  fall of  109 Douglas  f i r  comparable  to  in  both  experimental  treatments-  the  results  obtained  t o be no  measurable  in  the  This  spring  was  seeding  experiment. There fir  seeds  appeared  i n the s e e d - f a l l  t r a p s on  natural f a l l  any  of  the  of  Douglas  grids  during  1975-7 7.  DISCUSSION The  use  predation the  of  by d e e r  responses  alternative mice h a s  of  deer  densities.  In a l l  percentage  survival  from  sampling  eaten seeds  or  were  to  a  range  and  eaten  seed  found  as  assumption, cached  population  eaten  because  are u n l i k e l y  Besults  from  my  of  later.  I  logs,  small  proportion  seeds  taken  that seeds  even  removed  that  this  were  which a r e t y p i c a l of  were soon  seeds eaten  removed  i f they  found  are  (at l e a s t  the  from  is  the those  a  fair  never that  then  eaten-  seeds  may  assumption.  The  u n d e r stumps and  along  places that actually  and  were t a k e n and  radioactive seeding, indicating  seeds  of  R e g a r d l e s s o f when  believe  f i r seeds  t o germinate  cached  fallen  calculation  out of the guadrat  be moved a g r e a t d i s t a n c e , s u p p o r t s t h e a b o v e majority  f i r seed  i n an e q u i v a l e n t manner t o  remains. Douglas  seed  measuring  of Douglas  I have assumed taken  conifer  accurately  measurements  were e i t h e r and  on  lower  were e a t e n , t h e y were c o n s i d e r e d t o be  experimental seeds  mice  values,  cached  to  been b a s e d  response  quadrats  foods  mice  cached at the  inhabit.  suggests low  seed  that  The aost  density  of  110 1.92  kg/ha). Total  density 3.4  up t o a c e r t a i n  began  to  level  maintained t h i s  l a b o r a t o r y seed at  level  and 3.5, we s e e t h a t  day and  numbers a n d number  about  seeds/ha total  only.  Beferring  o f f at a density response  above  of  an  and  number  limit.  the  The  However,  the  derived  the  seed  the  from  the  field  Douglas  86 0,000  food  to differ  860,000  considered  experiments.  for  mice.  experiments  used a  the  fts  5:2:1  and  f o r e s t and  that  mentioned mice w i t h  in  should  the  r e s p e c t to  between h a b i t a t s ,  r e s p o n s e measurements i n t h e f o r e s t  has  deer  (ratios of  o f deer  were  on t h e c l e a r c u t  seed  for  had  squirrels  was  response  data  behaviour  i s unlikely  about  p e r mouse p e r day  o f 860,000 s e e d s / h a  foraging  f i r seeds  applicable In  density  stabilized  mice were no l o n g e r  and b i r d s  alternative  the  to t r y a l t e r n a t i v e  o f seeds  i n t h e l a b o r a t o r y seed t r i a l s .  results, Douglas  chipmunks  successful  in  with d e n s i t i e s g r e a t e r than  t h e measurement o f a s e e d  combined s e e d  obtained  of  seeds/ha  A t t h i s d e n s i t y , the  f o r attempting a l t e r n a t i v e  presence  complicated  7:1)  taken  T h u s , I assumed t h i s number  best density  p e r mouse p e r  430,000  of  o f new  In a d d i t i o n ,  most p r e v a l e n t on seed g r i d s seeds/ha.  m).  seed  Figures  seeds/ha  density  f t o r 86 s e e d s / s g  mice  upper  o f about 860,C0 0  seed  i n c r e a s i n g , and t h e number o f s e e d s reached  with  again to  taken  i t seemed l o g i c a l  a t a combined  (8 s e e d s / s q  increased  S i n c e t h e numbers o f a n i m a l s  860,000 s e e d s / h a ,  number  animals  t h e number o f s e e d s  trials.  seed experiments  o f new  and s o  be  egually  experiments  produced  t o c l e a r c u t areas*  general,  most  alternative  b e t t e r r e s u l t s i n the f o r e s t  seed  than i n c l e a r c u t  areas.  However,  111  the  excellent  both  h a b i t a t s d u r i n g the l a t e  late  fall  such  survival  of  o f Douglas fall  f i r s e e d was v e r y s i m i l a r i n o f 1976 and  the  a t these times, secondary  1977.  spring  seed  and  predators  a s c h i p m u n k s and v a r i o u s s p e c i e s o f s e e d - e a t i n g b i r d s  rare  or  absent  alternative seeds  by  (see  foods i n deer  chapter  suppressing  mice  4).  The  success  consumption  of  i s given f u r t h e r credence  were  of  these  Douglas f i r  by t h e f a c t  that  p o p u l a t i o n s o f P e r o m y s c u s m a n i c u l a t u s a r e a t peak  densities  the  1967; Fordham  fall  1971;  (see F i g u r e 1.5 and S a d l e i r  P e t t i c r e w and S a d l e i r  1965; H e a l e y  1974; F a i r b a i r n  1977;  and  in  Sullivan  1977). This  study  has  p r o v i d e d some f i e l d  evidence f o r the f u n c t i o n a l response deer  mouse.  Solomon  (1949)  as w e l l  as l a b o r a t o r y  of a general predator,  first  applied  the  terms  the of  f u n c t i o n a l and n u m e r i c a l r e s p o n s e s  to t h e two-fold nature o f the  response  density.  to  changes  demonstrated  in  t h a t deer  prey  tit  demonstrated  the  bordered  to  the  by t h e  demonstrated The  Hook e t a l .  and  Hook  (1960) have a l s o  t i t h a s an S-shaped r e s p o n s e  white  number  larvae,  of  meadow  moth  (Bupalus s p . ) .  cocoons.  of the great  same r e s p o n s e o f t h e b a y - b r e a s t e d  larvae.  great  the  acre  densities of sawfly  this  s p r u c e hudworm that  d e n s i t i e s of sawfly  (1960) h a s shown t h e f u n c t i o n a l r e s p o n s e  to different  (1959a)  mice i n p i n e p l a n t a t i o n s had an S - s h a p e d  f u n c t i o n a l response t o t h e varying Tinbergen  Helling  (1963)  warbler to suggested  to the density o f  The f u n c t i o n a l  response  j a c k p i n e s e e d s and s e e d l i n g s d e s t r o y e d p e r vole  by B u c k n e r  use o f a l o w e r  (flicrotus  pennsylvanicus)  has  been  (1972). palatability  alternative  food  ( o a t s ) by  112 itself in  a t a 7:1  survival  r a t i o produced  of  Douglas  alternative  foods  over  on  oats  were p r e s e n t  a  forest  This  i l l u s t r a t e d the  palatability  and  ratio  food  fir) The  high  o f two  September  the  to  Douglas f i r  produced  better  Eeichman  habitats food. mice  found  spread  i n f o r m a t i o n on  When and  I  (than  (see F i g u r e  Douglas  an  fir)  although  even  higher  food frem  uniform  the  seed  the  of deer  response of  the area  trial  alternative of  the g r i d  food  (1977), s m a l l p o c k e t just  as  (1977) f o u n d  would  captured  more p r e y  an a g g r e g a t e d responses  of  deer  as  southern from  pattern.  have  (1977)  clumped  grasshopper a  I do  mice  at  mice i n a r i d  effectively that  in  mice t o food  However, a c c o r d i n g t o E e i c h m a n  Taylor  of f o o d  dispersed not  to  know o f  different  resources.  provided deer  Douglas  (oats) food  produce  high  density  experimental  clumps  over  Oberstein  than from  an  lower  Perhaps  (Onychomys t o r r i d u s )  distributions  seed  not  scattered  Similarly,  distribution any  during  results. and  and  of Douglas f i r .  i n a seeding experiment, should  mice  of s u n f l o w e r  higher  d i s t r i b u t i o n of alternative  seeds.  locations  foods  preferred  o f a h i g h d e n s i t y and  slightly  two  seed.  did  several  were  the  where o n l y d e e r  combination  effects  increase  Shen  d e n s i t y (higher than  study,  clumped  1976,  seeds  grid  palatability  egual  in this  of c o n i f e r  random  and  lower  marginal  the best s u r v i v a l  with a  palatability  Changing or  positive  The  a  F i g u r e 3.7).  experimental  produced  mixed  and  use  not attempted survival  (see  (see F i g u r e 3 . 8 ) .  i n a 5:2:1  3.11).  f i r  more t h a n  were c o m p a r e d , s u n f l o w e r  oats  Douglas  no  f i r seeds  mice w i t h e q u a l amounts o f in  the  experimental  rooms  sunflower at  the  113 Animal of  Care  C e n t e r , t h e r e was no d i f f e r e n c e  6 trials.  at  least  i n preference i n 2  However, i n t h e o t h e r f o u r t r i a l s ,  t w i c e a s much s u n f l o w e r  as Douglas f i r .  t e s t s f o r d e t e r m i n i n g t h e p r e f e r e n c e o f deer fir  or  s u n f l o w e r , Keyes  (chi-square seeds.  allowed  and  (1978) f o u n d  when  Multiple  Range  t o c h o o s e from  field this  individual  their  a mixture  undefined content  with o t h e r seeds value  such  o a t s 3.90  f i r 7.13  as  (Smith  (Bingham  the l a b experiments,  and  sunflower  seeds  relative  caloric  Deer  mice  (1967),  mice  As e v i d e n c e d  which  over  6.82  my f i e l d  p r e f e r e n c e o f deer  presumably  optimize  provide  some  The c a l o r i c  was a s  follows:  (Mrosovsky  1S66) ;  s t u d i e s and  some  mice f o r D o u g l a s f i r  e q u a l and g r e a t e r t h a n  This trend corresponds i n much t h e  same  develop  what  might  be  i t  to the manner  a food source.  t e r m e d an Howard  ( 1 9 6 8 ) , and Howard and Marsh  have p r o v i d e d e v i d e n c e  f o r t h e use o f o l f a c t i o n  by d e e r  detecting  the  foods  By  their  (1977).  Howard e t a l .  food.  in  oats,  base  or moisture.  i n my s t u d y  T h u s , from  offered.  were  rodents  nutrition  " o l f a c t o r y s e a r c h image" t o e x p l o i t Cole  (ANOVA -  desert  (low i n e n e r g y )  used  of  laboratory tests.  c o n t e n t s of the seeds  as d e s c r i b e d by Reichman  choice  i n both  was a p p r o x i m a t e l y  f o r the other seeds  a  was p r e f e r r e d  1967); s u n f l o w e r  1977).  of  difference  c o n s i d e r a t i o n s but s t i l l  (kcal/gm) o f t h e s e e d s  Douglas  was  (1977),  Douglas  t o sunflower  o f s i x seeds.  was s i g n i f i c a n t  p r e f e r e n c e s on e n e r g y  diets  for  T e s t p=.05) when i n d i v i d u a l  A c c o r d i n g t o Reichman dietary  had  took  In laboratory  mice  mice  (see F i g u r e 3.8), s u n f l o w e r  difference  sice  no s i g n i f i c a n t  However, D o u g l a s f i r was p r e f e r r e d  Duncan's  the  a t p<.01)  the  use  of alternative  and  (1970)  mice  in  of v a r y i n g  114 p a l a t a b i l i t i e s and mice)  have  resulting  densities  switched decline  (Murdoch  in  the  Searching-image formation a  behavioural  switching For two  predators  processes;  flexible  learned  the  which  seeds  lowering  of the  stimulus  from  the  very  the  many  prey  to  alternative  food.  switch  (1973)  understanding  a  species  the  I  Of  conclude  in  conifer  prey  and  prey  was  i s an  the  a  eaten. can  be  effect  of  seed.  the as  way  has  predator's potential  mice  discussed response  to  more this  w e l l as the  obvious  deer  in  its  mouse  is  environment.  mouse's r e s p o n s e  the  strength  (1965) has  the  of  seed  Douglas  to the  discussed  strength  O l f a c t o r y cues,  from  a  retains  density of sunflower  deer  form  in  o p p o r t u n i s t i c omnivore  Holling when  flexible  generalist  The  the deer  decreased.  being  optimizes  (1976) c o n s i d e r s  items  some  of size,  the and  probably a l l f i r  to  the  importance  more  than  one  the  of prey  benefits for successful biological  what p r a c t i c a l u s e , that  Cornell  species.  predator  relative  interacted  control.  with  seeds  predators  image f o r m a t i o n  f u n c t i o n a l response  high  and  source  switching  image and  Such  must h a v e r e d u c e d  the  Murdoch  (deer  olfaction)  produce  Consequently,  D o u g l a s f i r by d e c r e a s i n g from  food  using  generalists,  image and  of search  general  stimulus  predators  conifer  case,  search  f r o m many d i f f e r e n t  Sunflower  of  could  1976).  of switching.  a  selecting  a  search  advantage o f t a k i n g certainly  are  (Cornell  efficiency  t o a new  number  which  forming  prey  essence  1969)  the  1973).  selecting  the  study,  (in this  mechanism  (Krebs  i n my  then,  are the  present  d e s t r u c t i o n of Douglas f i r seeds  (and  results? perhaps  115 other conifer of  high  procedure  seeds)  i s much r e d u c e d  palatability for  reforestation  and  applying  projects  by u s i n g  relative this  i s discussed  alternative  density.  biocontrol  The  foods  recommended  technique  i n chapter 5 of t h i s  in  thesis.  116 Figure seed  3.1.  Cumulative  densities  during  experiment density  in  1975.  number the  The  six  o f s e e d s t a k e n p e r ha a t f o u r weeks  maximum  after  number  i s r e p r e s e n t e d by a d a s h e d h o r i z o n t a l  of  each  seeding  seeds f o r each  line.  860 ,746 75CH  600 430,373  450H 300 O X CO  150  CD Q.  C •  CD CO  CO "D CD CD CO  9Q0i  860,746  750  CD _Q  E  600i  =3 C  CD >  -4—*  430,373  450-L  _C0  E  =3  o  300H  15(H  107,593  W e e k s after seeding  117  118  F i g u r e 3.2. Douglas  Responses  f i r  seed  of  numbers  densities  of  for  mice  the  over  a  study.  Each  of deer  density  responses represent the  two weeks a f t e r -  August  October  seeding.  1975; T r i a l  1977.  No.  These  T r i a l No. 3 - June  1 - July  (MNA)  1975; T r i a l  1976; T r i a l  No.  of  symbol  represents the response i n density o f s e e d s on a g r i d .  mice  range  to  the first  No.  2  4 - May t o  Number of mice per ha -L  t_  ro  I\D  r\3 O CO — —•—t-Q—C*>01> B>> • 1  o o  •  1  <j)  t> &  '  1  4^  t> >  o  o o  CO  o  o  •  •  CD O cr O  .c  3  CD  00  O O  CD CD  CL  "D  o o o  &)  (NO  x  o  c/> CD  O  O  _L w  ^  o o  CD O O 00  O  o  6TT  o  >  >  120 Figure  3.3-  Douglas of  mew  grid.  Responses  o f numbers o f new  f i r seed d e n s i t i e s .  Each s y m b o l  animals captured  in relation  These responses  represent  seeding*  Trial  Trial  3 - June  No.  No.  1 - July 1976; T r i a l  mice  the  a  represents  to the density first  1975; T r i a l No.  over  No-  two  range  of  t h e number  o f s e e d s on a weeks  2 - August  after 1975;  4 - Hay t o O c t o b e r 1977.  Number of new mice per ha CO  -^er»—&—«»— ©  —I  1)  CO 1  O  IV) I ;  _1  o  IV)  o o o o c  3 cr  •  o  •  o o  CD O "  CD  o  o  CO  -^  U) CD CD  Q.  C/)  pe  — ^ 3"  o o 1  o o  CO  ro  o  L  o X o O O CD O O 00  O O  TZT  o  >  .  4^  L_  122 Figure 3 . 4 day  at d i f f e r e n t  represents day  The number o f D o u g l a s f i r s e e d s  the  seed d e n s i t i e s  July Trial  the  1975; T r i a l No.  the  forest-  Each  symbol  r e s p o n s e i n number o f s e e d s t a k e n p e r mouse p e r  t o a g i v e n d e n s i t y o f seeds  represent  in  t a k e n p e r mouse p e r  first No.  t«o  on  a  weeks a f t e r  2 - August  4 - Hay t o O c t o b e r  gridseeding.  1975; T r i a l  1977.  These  No.  Trial  responses No.  3 - June  1 1S76;  220O 20001800DOUGLAS  SQUIRREL  ??  16001400o  1200-  DEER  1000-  MOUSE  A o  800600 400H  o  200  1  0  2  200  4  400  8  600  800  12  1000 N u m b e r of  1200 seeds  16  1400  1600  per sq. foot  1800  per ha x10  124  Figure 3 . 5 . day  at  The number of Douglas f i r seeds taken per mouse per  different  environment.  Each  seed . d e n s i t i e s closed  circle  in  a  represents  number o f seeds taken per mouse per day t o a seeds.  simulated  forest  the response i n  given  density  of  1200H "O i_  CD  a  CD CO 13  o E i_  CD d  1000H e  800-  •  • ©  C  CD  XL  CO  600H  CO "D CD CD CO  400H  s  200H  1  0  2  200  4  400  600  8  800  12  1200 1400 1000 Number of seeds  16  1600  1800  per sq. foot  ,  per ha x10"  126 F i g u r e 3.6. sunflower itself. used  Percentage seed  The  on one  survival  ccopared  with  same p r o p o r t i o n forest  grid  and  of a mixture that  of control  (7 s u n f l o w e r one  o f D o u g l a s f i r and  clearcut  D o u g l a s f i r by  : 1 Douglas grid  i n August  fir) 1976.  was  August  1976  128 F i g u r e 3.7oats  Percentage s u r v i v a l  compared  same p r o p o r t i o n grid  and  with that (7 o a t s  one c l e a r c u t  o f a m i x t u r e o f D o u g l a s f i r and  of c o n t r o l  Douglas  : 1 D o u g l a s f i r ) was  grid  i n August  1976.  f i r by  itself-  u s e d on one  The forest  129 100  4. s  80  Forest  -J k' i  60  J  A A  A A  ;  A A  40-J  A  A A* i  A'  ^1  A»  20 H  <U W  A»  o  tf  C8 > •H  Week  >  rr; A A:  1  . A  0  a•  CO QJ  100 H  ca  A  c o  M OJ  J  80 H  p. 60  J  40  H  Clearcut  A  U fl  A a  20  J  a  a  ft  X3. Week  0  August 1976  m.  130  Figure  3.8.  Percentage  survival  s u n f l o w e r s e e d , and o a t s compared fir  by  oats  : 2 Douglas  in  August  itself.  1976.  The  of a mixture of Douglas f i r ,  with that  same p r o p o r t i o n  f i r ) on  one  forest  was  grid  of used  and  one  control  Douglas  (3 s u n f l o w e r : 3 clearcut  grid  August  1976  132  Figure  3.9.  sunflower itself. used  Percentage seed  compared  with  that  on b o t h  week  clearcut grids  of Douglas  of c o n t r o l  The same p r o p o r t i o n (7 s u n f l o w e r  of sunflower second  s u r v i v a l o f a mixture  : 1 Douglas  i n November 1976.  s e e d was a g a i n d i s t r i b u t e d (sequential seeding).  Douglas  on one  f i r by  f i r ) was  The same grid  f i r and  density  after  the  November  1976  134  Figure and  used  The  survival  The same  grids  density  2 of the 4 grids after v a l u e s g i v e n f o r each  of seed  from  with  same p r o p o r t i o n  on a l l c l e a r c u t  1977.  The  Percentage  s u n f l o w e r seed compared  itself.  on  3- 1 0 .  that  o f a mixture of Douglas f i r of control  Douglas  (7 s u n f l o w e r : 1 D o u g l a s  i n this  experiment  o f sunflower seed the second 2-week  week  period  2 experimental grids.  from  March  was a g a i n  f i r by fir)  was  to  May  distributed  (sequential  a r e the average  seeding). survival  100H  A  /  A  80"  Clearcut  , ,  A  A  ,  ,  ,  .  A  A A  A  > A  60  H  > A  A  A  , ;  A  40'  *1  20 H  4  A  A A  .; ,. a  a  A a  A  ;  A 0  Week  i  8  100 H  >! 80  H  60 1  A A A A A A A  a 1  -Sequential seeding  i  A A A  40 H  J:  20  f  A  A  A A  A  Week  March  April  May  136  Figure and  3.11.  Percentage  survival  s u n f l o w e r s e e d compared  itself. used  The  same p r o p o r t i o n  cn a l l f o r e s t g r i d s  1977.  with t h a t  The same d e n s i t y  of a mixture of c o n t r o l  i n t h i s experiment  from  March  o f s u n f l o w e r s e e d was a g a i n the second  The  2-week p e r i o d  o f seed from  Douglas  (7 s u n f l o w e r : 1 D o u g l a s  on 2 o f t h e H g r i d s a f t e r v a l u e s given f o r each  of Douglas f i r  two e x p e r i m e n t a l g r i d s .  week  f i r by fir)  was  to  May  distributed  (sequential  a r e t h e average  seeding). survival  137  138  Figure  3.12.  sunflower fir  by  Douglas to  s e e d , and o a t s compared itself.  fir)  Douglas  November 5:2:1  Percentage s u r v i v a l  experimental  with t h a t  proportion  was used on two g r i d s f i r was  1977. ratio  The same  used  o f a mixture  on  grids.  the  average  control  fir,  Douglas  (5 sunflower : 2 o a t s : 1  and a 7 : 1 r a t i o  a third  The v a l u e s g i v e n f o r e a c h are  of  c f Douglas  grid  of  oc t h e c l e a r c u t i n  2-week p e r i o d  survival  sunflower  cf  seed  for from  the two  140 Table 3.1. Trappability estimates for Peromyscus maniculatus on the six experimental grids and one control grid i n the forest. Sample size i n parentheses. Maximum trappability i s the proportion of those known to be alive that are actually caught i n a trapping session. Minimum unweighted trappability estimates f i r s t and last captures and provides only one value for each individual regardless of how long he lives. Experimental populations Grid B Males  Grid C  Females Males  Grid D  Females Males  Grid E  Females Males  Females  Maximum trappability 1975  .84(25)  .91(16) .91(23) .88(27) .96(19) .95(8)  .98(14) .96(19)  1976  .88(16)  .68(19)  -  .66(17) .83(15)  1977  -  -  --  1975  .84(14)  .74(9)  1976  .88(9)  .58(15)  -  1977  -  -  -  -  -  .81(21) .61(15)  Minimum unweighted trappability .90(17) .81(14) .89(9)  .75(4)  -  Grid F  -  -  Males  .79(18) .64(15)  Control population.  Grid P Females  .85(5)  .62(15) .71(12)  Experimental populations  Males  .89(9)  Grid A  Females  Males  Females  Maximum trappability 1975  0.91 (20) 1.00 (17)  1976  -  -  1977  -  -  -  -  0.95 (15) 0.99 (17)  -  -  0.98 (12) 0.97 (15)  0.81 (60) 0.83 (47)  0.73 (41) 0.79 (29)  Minimum unweighted trappability 1975  0.57 (10) 1.00 (9)  1976  -  1977  -  —  -  -  0.68 (38) 0.75 (33)  0.89 (14) 0.93 (14) 0.97 (8) 0.91 (12) 0.76 (34) 0.77 (19)  141  T a b l e 3.2.  Mean number o f seeds p e r stomach a t two d i f f e r e n t seed Grid M  Seed/density/acre  Mean number o f seed integuments i n f u l l stomachs  Number o f f u l l  stomachs  T o t a l number o f mice  Aug. 19-21  522,720  50.1  Grid M  densities. Sept. 19-21  53,240  63.1  9  12  16  15  142 Table 3.3. Number of deer mouse seed caches and proportion of whole and eaten radio-tagged Douglas f i r seeds found adjacent to seeded 0.10 ha forest and clearcut grids.  Number of locations  Forest  17  Clearcut 9  One whole  Parts of one  seed(radiotagged  eaten seed .  present 14  . . _.  Caches with  one  seed  (radiotagged) (whole or eaten) 1 (83 whole)* 4 (each with ca. 5 seed fragments) 3 (each with one whole seed and 2-3 seed fragments)  * This cache may be from a chipmunk rather than a deer mouse.  143 Appendix 3.1. Mean values, standard e r r o r s , and 95% confidence l i m i t s f o r number of seeds eaten and taken per sampling unit(0.093sp.m) . n=no. of sampling u n i t s .  Douglas f i r seed (2 weeks a f t e r seeding) Experimental T r i a l No. 1 - 1975 Densitv/ha mean  SE  95% C L .  Experimental T r i a l No. 2 - 1975 Densitv/ha mean  SE •  95% C L .  107,593  0.58  0.15  0.25-0.91 107,593  0.75  0.04  0.66-0.84  215,186  1.00  0.25  0.46-1.54 215,186  •1.77  0.04  1.68-1.86  430,373  2.50  0.36  1.71-3.29 430,373  2.68  0.14  2.40-2.96  860,746  2.67  0.59  1.36-3.98 860,746  5.75  0.33  5.07-6.43  9.46  0.11  9.24-9.68  8.70  0.31  8.07-9.33  15.06  0.18  14.69-15..  Experimental T r i a l No. 3 - 1976 107,593  0.87  0.03  0.81-0.94  3.52  0.11  3.30-3.74  n-100 430,373 n=50 Experimental T r i a l No. 4 - 1977 107,593  0.95  0.02  0.91-0.99 1,075,932 n=50-  -.- n=99 860,746  7.40  0.12  7.16-7.64 1,291,118 n=50  n=50 860,746  7.54  0.09  7.37-7.71 1,721,491 n=50  n=50 1,075,932 n=50  7.70  0.29  7.11-8.29  144 /Appendix 3.1. (cont'd) Douglas f i r seed and alternative seeds August 1976 Experimental T r i a l No. 1.  Seed densities/ha  Oats  Sunflower  Douglas f i r 95% C L .  mean SE  95% C L .  mean  SE  0.58  0.07 0.43-0.73  0.34  0.07 0.20-0.48  1.06  0.12 0.83-1.29  1.22 0.15 0.93-1.51  0.37  0.07 0.22-0.51  0.26  0.12  0.05 0.03-0.21  0.42  0.08 0.25-0.58  mean SE  2 weeks Forest 7:1 ratio 753,151:107,593  2.58  0.30 1.98-3.18  n=45 7:1 ratio 753,151:107,593  3.98 0.34  n=50 3:3:2 ratio 322,779:322,779:  2.66 0.09  215,186 n=50 Clearcut 7:1 ratio 753,151:107,593  0.08 0.10-0.42  n=46 7:1 ratio 753,151:107,593 '  1.62 0.23  n=50 3:3:2 ratio 322,779:322,779: 215,186 n=48  0.63  0.14 0.33-0.92  0.38 0.10  145 A p p e n d i x 3.1. (cont'd) Douglas f i r seed and a l t e r n a t i v e seeds A u g u s t 1976 E x p e r i m e n t a l • T r i a l No. 1  Douglas f i r  Sunflower  Oats  Seed d e n s i t i e s / h a mean  SE  95% C L .  0.28  0.06 0.15-0.41  0.16  0.05 0.05-0.27  0.60  0.10 0.39-0.81  0.20  0.06 0.08-0.31  0.04  0.03 0.02-0.10  0.10  0.05 0.01-0.19  mean  SE. _~ 95%C.L.~.-,-mean  0.65  0.15 0.35-0.95  SE  4 weeks Forest 7:1 r a t i o 753,151:107,593 n=49 7:1 r a t i o 753,151:107,593  1.78  0.19  0.06  0.02 0.01-0.11 1.28  0.11  0.00  0.00 0.00-0.00  n=50 3:3:2 r a t i o 322,779:322,779: 215,186 n=50  Clearcut 7:1 r a t i o 753,151:107,593 n=46 7:1 r a t i o 753,151:107,593  0.38  0.07  0.00 0.00-0.00 0.29  0.06  n=50 3:3:2 r a t i o 322,779:322,779: 215,186 n=48  0.00  Appendix 3.1. (cont'd) Douglas f i r seed and alternative seeds November 1976  Experimental T r i a l No. 2 Douglas f i r  Sunflower  Seed densities/ha 95% C L .  mean SE  95% C L .  mean  SE  0.02  0.02 -0.02-0.06  0.50  0.07 0.36-0.64  1.16  0.18 0.78-1.54  0.40  0.07 0.26-0.54  0.72  0.11 0.49-0.95  0.02  0.02 -0.02-0.06  0.40  0.07 0.26-0.54  0.26  0.06 0.14-0.38  0.30  0.07 0.17-0.43  0.56  0.09 0.37-0.75  2 weeks Clearcut 0:1 ratio 107,593 n=50 7:1 ratio 753,151:107,593 n=50 7:1 ratio 753,151:107,593 (sequential) n=50 4 weeks Clearcut 0:1 ratio 107,593 n=50 7:1 ratio 753,151:107,593 n=50 7:1 ratio 753,151:107,593 (sequential) n=50  Appendix 3.1.(cont'd) Douglas f i r seed and alternative seeds March to May 1977 Experimental T r i a l No. 3  Seed densities/ha  Douglas f i r mean .. SE  sunflower 95% C L .  mean SE  95% C L .  2 weeks Forest (all 7:1 ratios) 753,151:107,593  0.62  0..07 0..48--0..76  3.60  0.,29 3.03--4..17  0.68  0..07 0..55--0..81 5.12  0..32 4.48--5..76  0.84  0..05 0..73--0..95 4.22  0..35 3.53--4..91  0.69  0..07 0..55--0..82 v. 17  0..36 3.45--4..88  0.48  0.07 0.33-0.63 2.96  0.33 2.29-3.63  0.58  0.07 0.44-0.72  4.42  0.27 3.88-4.96  0.52  0.07 0.38-0.66 2.66  0.24 2.18-3.14  0.52  0.07 0.38-0.66  0.21 0.66-1.50  .0.13  0.03 0.06-0.20  n=50 753,151:107,593 n=50 753,151:107,593 n=50 753,151:107,593 n=48 Clearcut  (all 7: ratios)  753,151:107,593 n=48 753,151:107,593 n=50 753,151:107,593 n=50 753,151:107,593 n=50 0:1 ratio 107,593 n-98  1.08  148 Appendix 3.1. (cont'd) Douglas f i r seed and alternative seeds March to May 1977 Experimental t r i a l No. 3  Douglas f i r Seed  sunflower  densities/ha  mean  SE  95% C L .  mean SE  95% C L .  4 weeks Forest (all 7:1 ratios) 753,151:107,593  0.56  0.07 0.42-0.70  5.04  0.47 4.09-5.99  0.36  0.07 0.22-0.50  5.00  0.49 3.99-6.01  0.68  0.07 0.55-0.81  1.90  0.26 1.37-2.43  0.42  0.07 0.27-0.56  0.38 0.07 0.24-0.52  0.05  0.02 0.01-0.09  n=50 753,151:107,593 n=50 753,151:107,593 n=50 753,151:107,593 n=50 0:1 ratio 107,593 Clearcut  1 ratios) (all 7:  573,151:107,593  0.49 3.21-5.25  0.42  0.07 0.27-0.50  4.23  0.56  0.07 0.42-0.70  1.94 0.26 1.41-2.47  0.30  0.07 0.17-0.43  0.28 0.06 0.15-0.41  0.38  0.07 0.24-0.52  1.72 0.33 1.05-2.39  0.11  0.03 0.05-0.18  n=48 753,151:107,593 n=50 753,151:107,593 n=50 753,151:107.593 n=50 0:1 ratio 107,593 " n=98  149  Appendix 3.1. (cont'd) Douglas f i r seed and alternative seeds November 1977 Experimental T r i a l No. 4  Douglas f i r Seed densities/ha  sunflower 95% C L .  mean SE  oats  mean  SE  95% C L .  mean SE  0.65  0.05 0.55-0.75  0.63  0.07 0.47-0.79  0.58  0.07 0.44-0.72  0.30  0.05 0.19-0.41 1.28  0.10  0.74  0.06 0.61-0.87  0.74  0.13 0.47-1.01 1.64  0.06  0.48  0.05 0.38-0.58  0.15  0.04 0.07-0.23  0.46  0.07 0.32-0.60  0.02  0.01-0.01-0.05.0.28 0.08  0.54  0.07 0.40-0.68  0.00  0.00 0.00-0.00 0.74  2 weeks Clearcut 7:1 ratio 753,151:107,593  .  n=100 5:2:1 ratio 537,965:215,186: 107,593 n=50 ... 5:2:1 ratio 537,965:215,186: 107,593 n=50 4 weeks Clearcut 7:1 ratio 753,151:107,593 n=100 5:2:1 ratio 537,965:215,186: 107,593 n=50 5:2:1 ratio 537,965:215,186: 107,593 n=50  0.10  Appendix 3.2. Douglas f i r seed responses of deer mice i n the forest. The total number of seeds taken per hectare and total number of mice per hectare are given as i s the time span over which each experimental t r i a l was conducted. I n i t i a l no. of seeds/ha  T r i a l Total no. of no.  seeds  Number of Number of Number of seeds mice/ha  days  taken per mouse per day  taken/ha  203.2  1  80,694.9  20.9  19  2  62,762.7  22.2  14  4  102,158.9  35.8  12  237.8  4  93,606.1  34.6  14  193.2  215,186  1  190,782.8  23.5  19  427.3  (2 seeds/sq. ft.)  2  107,593.2  19.8  14  388.1  430,373  1  288,350.3  27.2  14  757.2  (4 seeds/sq. ft.)  2  378,728.1  34.6  13  842.0  3  268,983.0  29.6  14  649.1  860,746  1  286,915.2  23.4  14  872.1  (8 seeds/sq. ft.)  2  618,660.9  35.8  14  1234.4  4  796,189.7  60.5  14  940.0  4  811,252.7  54.3  14  1067.2  1,075,932  4  828,467.6  28.4  14  2083.7  (10 seeds/sq. ft.)  4  1,017,831.7  53.1  12  1597.4  1,291,118  4  936,060.8  42.0  12  1857.3  4  1,620,353.6  51.9  15  2081.4  107,593 (1 seed/sq. ft.)  201.9  (12 seeds/sq. ft.) 1,721,491 (16 seeds/sq. ft.)  151  CHAPTER 4  SEASONAL ABUNDANCES OF CONIFER SEED IBEDATOBS  INTRODUCTION Little with  i s known a b o u t t h e b e s t  of  year  r e s p e c t t o low p o p u l a t i o n s o f s e e d - e a t i n g  birds.  Seed-eating  densities 1960)  during  and Oregon  inactive  of  on c l e a r c u t  shorter  i n other  (see D u n f o r d  chipmunks  not  1968, 1 9 6 9 ) . p l a c e s such  1974; S k r y j a  be  as  chipmunk  physiological  severe  the  amcenus)  a  or  Orich  1977).  inactive  tend  zone  to  i s considered hibernators  northwestern  these  United  climatic  chipmunk species  be  coniferous may be States,  conditions  more n o r t h e r l y l a t i t u d e s . to and  The be  a  non-  (Eutamias  ( S t e b b i n s and  chipmunk s p e c i e s a r e g e n e r a l l y  below g r o u n d  throughout  (Bagar  This period of i n a c t i v i t y  between  P o p u l a t i o n s o f Peromyscus be p r e s e n t  spp.)  temperate  non-hibernating  However, b o t h  and d i s a p p e a r  in  striatus)  whereas  o r a t very low  1968).  (Eutamias  in  intermediate  seeding  California  as t h e southwestern  as  f'Tamias  poor  in  1974) where l o c a l  hibernators, i s  areas  for  s m a l l mammals and  t o be a b s e n t  and Ward  f r o m November t o A p r i l fSheppard  eastern  appear  (Gashwiler  forests  may  birds  winter  Populations  can  time  during  maniculatus  winter. do n e t h i b e r n a t e  a l l months o f t h e y e a r .  and  Deer m i c e a r e  152  most  abundant  chapter 1971;  i n the  1 in this  fall  thesis  Petticrew  and  I f the  thesis  i s to  by  mice, chipmunks,  deer  seeding  (in  biological used  least  1974;  control  and to  m u s t be  abundant  Sadleir  1965;  technique  in  this  determine  the  abundance  of  chipmunks  throughout  the  documented  and  combine  f o r deer  July  traplines  (Burn-  weeks w i t h m  long  traps  to  25  at  following  day  1,  between  lines  usually  trapped  and after  Sullivan i n  seed  best  this damaqe  time  and  for  seedling  was  and  designed  seed-eating  knowledge  with  to birds  what  i s  METHODS  1977,  two  S l a s b - c l e a r c u t ) were l i v e - t r a p p e d  every  two  and  line  located at The  mice except the  same  afternoon of grids  March  Each  each s t a t i o n *  checked  morning and  and  November  t o t h a t f o r deer  morning of  MD  1976  trap stations  were p l a c e d  chapter  this  Sherman l i v e - t r a p s .  with  similar  November  and  Fordham  mice.  MATEBIftlS  From  the  (see  determined.  outlined  already  1977;  germination  study  year  1967;  conifer  then  favourable  spring  described  to reduce  birds,  i n the  Healey  Fairbairn  successfully  relation  establishment) The  and  Sadleir  1977).  be  and  i n the  completion  day  to  was  approximately  900  37.5-m i n t e r v a l s .  Two  trapping  procedure  t h a t t r a p s w e r e s e t on  the  afternoon,  the  2.  To  and  the  then  avoid interference  same a r e a , chipmunk of  was  deer  mouse  lines  were  trapping  153  period  o r on  all  alternate  chipmunks  seeks.  captured  balances,  sexed,  and  fingerling  fish  tags.  noted  by  p a l p a t i o n of  openings  and  determined of  by  animals  interval  e n u m e r a t i o n and  February  were  mornings, each was  to  usually  recorded.  grid  counting  grid. than  Care once.  weeks  The  10 A.  were  as t h e  study H.  walked t h e  'C  1  was  not to/ enumerate an  were a b u n d a n t  number  the  one  and  During  (G, H, «E*  July  during these  days  of  seasons  of  of J)  each  on  that  bird  more  every  two  number o f b i r d s  and  the  I , and  lines  individual  or two  different in  seed-eating  were s i g h t e d a n d / o r h e a r d  i n f o r m a t i o n on t h e  censused  was  number o f b i r d s  four grids  which  not  minimum  area.  , the  a l l birds  s p e c i e s per h e c t a r e over  species  each o f t h e  observer  provided  Population size  p o p u l a t i o n s of  T h i s c e n s u s o c c u r r e d on  and  Birds  1977,  between 8 t o  taken  vaginal  birds  Burn  on  of  was  a t e a c h c o n s e c u t i v e two-week  the  s p e c i e s observed  at  (MNA)  numbered  1976).  November  censused  females.  spring  performance  the c o n d i t i o n  calculated  to be a l i v e  Populations of seed-eating  birds  the  Pesola  serially  on b r e e d i n g  male t e s t e s and of  on  with  Information  (see H i l b o r n e t a l .  From  weighed  ear-tagged  mammaries  known  were  cf each  the  August, although  year. most  months.  SESULTS  Chipmunk The Burn  and  populations seasonal variation  i n density  Slash t r a p p i n g areas  of  chipmunks  i s shown i n F i g u r e 4.1.  from In  the 1976,  154  the  number o f  weeks  of  animals  trapping,  began  declining  into  hibernation.  April  1977  and  on  the  and  Burn i n c r e a s e d d u r i n g  later  i n October  as  summer  animals  Chipmunks  were  by  the  initial  recruitment.  Density  i n both  reappeared  present  on  the  study  in  areas  late  study  area  went  March-early until  late  October. populatiens The density The  hectare throughout  dark-eyed  junco  was  Most s p e c i e s o f  very  abundant became  birds  s i x m o s t common s p e c i e s o f per  study. at  of seed-eating  low  the  these  densities  on  the c l e a r c u t .  less  numerous,  favourable  1977  up  are  shown  most a b u n d a n t seed-eating  to In  late late  probably  regions f o r the  seed-eating  birds in  their  Figure  4.2.  species during  birds  were  M a r c h , when t h e y October, owing  and  these  to  this  absent  or  became .birds  migration  more again  to  more  winter.  DISCUSSION Many s p e c i e s o f  birds  which  i s consumed e i t h e r  ground  after  Among  birds,  southern  1947;  juncos  meadowlarks  fZenaidura avian  natural  macroura)  conifer and  (1976), the  and  s m a l l mammals f e e d  directly  seed-fall  or  on  the  parent  following  ( J u n c o _spj3.) , r o b i n s (Sturnella are  seed  predators  Eastman  1960)-  typical  magna),  According  s p e c i e s that p r e f e r or  are  1938; to  tree  direct  and  seed,  t r e e s or cn  (Turdus  of those  (Burleigh  on  seeding.  migratorius) ,  mourning  cited Smith  the  as  doves  important  and  Aldous  E u n n e l l and  Eastman  restricted  to  recently  155  logged  areas  are  primarily  Numerous s t u d i e s have species  increases  climax f o r e s t only  the  report the  on  the  succession  and  (see r e v i e w  Hagar  areas  the  winter.  logged  absent  o r a t v e r y low  spring and  from  from  ward  (1968)  be  April  studies  of  results  are  generally fall  and  comparable  concluded reappear  seasonal  during both  seed-eating  during  the  Pecomyscus generally  and  early  b i r d s and  probably  much  reduced  Thus, they  winter  and  (1960) and  from  their  in  on  were early  Gashwiler  indices  of  year. (1968,  those  in  the  (i.e.  spring.  1969)  provide  chipmucks, my  and  study.  spring  in  some these  It  areas  may  be  in  the with  temperate zone w i n t e r s ) .  present  on  clearcut  areas  In a d d i t i o n ,  populations of  chipmunks are a t t h e i r  lowest d e n s i t y  before  a l l  of  e a t e r s were p r e s e n t  the  abundance o f  i n weather  maniculatus active  would  or  October-  results the  above g r o u n d  spring  (1968)  seasons  location  absent  Hagar  E u t a m i a s amoenus i s n o t  the w i n t e r  Ward  t h a t c h i p m u n k s h i b e r n a t e a t some t i m e  variations  Consequently,  were  and  However,  when  March.  to  and  the  valuable f o r determining  Sheppard  i n f o r m a t i o n on t h e s e a s o n a l  d e c l i n e s as  the  during  throughout  type  bird  of  to l a t e  densities  of  1975).  Gashwiler  a v i a n seed  reported similar  the d e n s i t y o f b i r d s The  study,  November t h r o u g h  then  Data o f t h i s  but w o u l d s t i l l  areas  diversity  Balda  with r e s p e c t t o s i t e  In t h i s  Fringillidae).  species in different  p o p u l a t i o n s of s e e d - e a t i n g b i r d s during  by  (1960) and  several years.  variation  (Family  that  abundance o f b i r d  for  show g r e a t clearcut  i s attained  the  year  indicated  during  s t u d i e s of  sparrows  breeding  also winter,  commences.  follow except  this  Populations  pattern,  but  perhaps i n areas  with  of are an  156 extreme w i n t e r of  torpor  seeding  with  c l i m a t e , where t h e y  (Falls  1968).  r e s p e c t t o low  may  enter  Therefore, populations  the of  temporary very  best time f o r  seed-eating  mammals and b i r d s i s i n t h e l a t e w i n t e r - e a r l y s p r i n g . period  fits  c o n i f e r seed  i n w e l l with germination.  periods  t h e presumed most f a v o u r a b l e  This  small time  time f o r  157  Figure  4-1-  lines  during  alive  (MNA)  against in  numbers o f chipmunks on 1976-77-  for  25  trap  Minimum  which  number o f  stations covering  t i m e e x c e p t f o r the  density  the B u r n  represent  fall  900  d e c l i n e s and  number o f a n i m a l s  ana  Slash  trap-  a n i m a l s known t o m has  been  spring captured.  be  plotted  increases  55T  J  A S 1976  O  N  D  J  F  M  A  M  J  J  A  S  O  159  Figure  4.2.  Numbers  of  s p e c i e s on t h e Burn s t u d y the  number  different July  of  grid  and A u g u s t  birds  areas.  t h e s i x most common s e e d - e a t i n g area.  per  Each c l o s e d  hectare  as  an  circle average  represents from  The d a s h e d l i n e r e p r e s e n t s t h e p e r i o d  when b i r d s were n o t c e n s u s e d .  bird  four in  160  7' &  5 4 3 2 1 5. 32 1-  4  5 4 3 2 1 5 4 3 2 1 5 4 3 2 1 5 4 3  1977  161  CHAPTER 5  BEFOBESTATION  BY DIRECT SEEDING WITH COHIFES SEED  AND SLTEBNATIVE FOODS  INTRODUCTION Reforestation of seed  h a s l o n g been  Destruction adversely {see  of cutover  of  the  affected  reviews  by B l a c k  These  chipmunks  (Eutamias  as  seed  the  19 69;  authors  important  seeding  regenerating  has  forests  great potential States, direct  seeding  of  rodent  chemical  repellents  deer  mice  conifer  of North  projects  1973; a n d Pank  (Peromyscus  species seed  of  spp.),  seed-eating  predators  failed  as  a  means  i n Canada even t h o u g h t h e t e c h n i q u e 1973).  Similarly,  in  the  has d e c l i n e d d r a m a t i c a l l y i n r e c e n t  (Abbott  i n the  America*  p r e d a t i o n on c o n i f e r  control  America.  reforestation  seed  of  offers United years  and t h e b a n n i n g o f  1973).  Two b a s i c a p p r o a c h e s t o r e d u c i n g c o n i f e r conventional  North  1970; B a d v a n y i  generally  <see C a y f o r d  because  of these  s p p . ) , and v a r i o u s  most  in  application  by s m a l l mammals and b i r d s has  Radwan list  l a n d by d i r e c t  foresters  supply  temperate c o n i f e r o u s f o r e s t s Direct  of  the success  1974).  birds  a goal  forest  methods,  which  have  seed  predation are  mainly  involved  16 2  chemicals, forest  and  managers i n t h e  techniques birds.  poison b a i t s , None  Consequently, dominated  by t h e  of  from  and  (Walters  the  methods  and  Klinka of  make  alternative  foods  a  applying  the  reforestation alternative  I discuss  biological  the  successful.  be  has  the  five  1977) .  times The  and  those  low  seed  technique seeding  of  efficiently for  restocked  p r e d a t i o n by  the  solution by  of  cost of  a favourable technique  direct  recommended  direct  become  cultivation  non-chemical  control  programs u s i n g  been forests  problem o f o b t a i n i n g s u c c e s s f u l r e f o r e s t a t i o n In t h i s c h a p t e r  applied directly  of u n s a t i s f a c t o r i l y  of c o n i f e r  offers  mechanical  quickly i t  numerous  included  of  o f s e e d l i n g s and  the tremendous b a c k l o g  Biological control  century,  seed-eating  has  regeneration  areas  a  and  repellents  techniques  possibility  large  half  rodents  However, p l a n t i n g c o s t s may  regenerating  lands.  almost  N o r t h w e s t have d e v e l o p e d  chemical  these  planting  seeding  reforesting  of  and  artificial  plantations.  seeding  Pacific  For  f o r p r o t e c t i n g t r e e seed  seeds.  direct  control.  These c o n v e n t i o n a l c o n t r o l  devices, to  biological  use  to  seeding.  procedure  (see c h a p t e r  of c o n i f e r  the  seed  for 3)  in fcith  foods.  BESDLTS  Direct seeding The and  with  results  alternative  Douglas f i r seed  of experimental foods  and  direct  i n a uniform  alternative seeding  distribution  with on  foods Douglas f i r  the  clearcut  are  presented  the  spring  1977  experimental also  i n F i g u r e 5.1.  trials  produced  also  spring  excellent  be e x p r e s s e d  (assuming, 0. 10 kg  experiment  results  on  survival  as t h e  1976  The  the  D o u g l a s f i r s e e d / h a , and  and  seed.  area  that  as  from  well  1977,  of c o n i f e r  seed  and  5:2:1  may  ratios  seedlings  seeds  may  per  i s direct-seeded  the  as  which  These r e s u l t s  number o f  cutover  3}  and  7:1  of c o n i f e r  potential  i n this case,  of  survival  conditions.  have been c o m p i l e d  (see c h a p t e r  i n the l a t e f a l l  valid  be a p p l i e d t o produced  seeding  These data  ha with  successfully  germinate). Application The  in reforestation  biological  projects  technigue  described  thesis f o r regenerating cutover f o r e s t in  the l a t e w i n t e r - e a r l y s p r i n g  on  local  In a r e a s  winter  w i l l have d i s a p p e a r e d  allow  the n e c e s s a r y  mixture  of  clearcut  i s as f o l l o w s :  conifer  seed  sunflower  distributed wet  7 kg  on c l e a r c u t s  subzones)  and  (i.e.  should not  in direct seed  0. 10  be  lowland  to  an a r e a  this  kg  oats  seeding  should  ha.  This  British  by  This  seeded seed  suitable swamp a r e a s  sites  for  over  or  a  ether kg  mixture  be  wet  Areas growth  or h i g h e l e v a t i o n  The  w e i g h t ) t o 56  f i r (dry and  Columbia.  will  paramount  may  i n t h e C o a s t a l W e s t e r n Hemlock Douglas  or  ( A r n o t t 1973).  f i r  of seeds  applied depending  of  aerially  Douglas  per  is  this  i s legged.  snow  which  be  number  Coastal  b i e g e o c l i m a t i c zones of seeding  moisture,  (equivalent  s e e d and  be  b e f o r e s e e d i n g commences.  seedbed  f o r germination  recommended  year a f t e r  snow c o v e r , most o f  soon  importance  lands should  3 of  (February-March-April,  snow c o n d i t i o n s ) i n t h e with  i n chapter  (dry  and  subzenes)  chosen  for  of Douglas f i r sites).  164  To o b t a i n a random o r u n i f o r m seed  must  the c o n i f e r  and  soaked  seed  in  1977).  T h i s procedure  2-  4-week p e r i o d  to  within  the average  showed e x c e l l e n t  The  suggested direct  Econcroic  must be s t r a t i f i e d  growth  hormones  trees,  the  for at least  (see H a l t e r s and  In  three Klinka  s h o u l d promote s e e d g e r m i n a t i o n w i t h i n after  direct  l e n g t h o f time  seed  in  of  be d i s p e r s e d e v e n l y o v e r t h e a r e a o f t h e c l e a r c u t -  addition, weeks  distribution  survival  procedure  seeding-  This period  a  i s well  (4 weeks) i n which D o u g l a s f i r  during  my  f o r applying this  spring  experiments.  biological  technique  s e e d i n g o p e r a t i o n s i s summarized i n F i g u r e 5.2aspects  The  cost  cf seeding c o n i f e r seed  this  new  reforestation  based  on t h e f o l l o w i n g :  D o u g l a s f i r seed  $90-00/kg  sunflower seed  $0.64/kg  oats  x  $0.12/kg  Distribution Total cost  technique  7 kg =  o f seed  x  x  0-10  56 kg =  and a l t e r n a t i v e is  kg =  foods  approximately  in  $64.68/ha  $9.00  $44.84  $0.84  mixture  $10.00/ha  $64.68/ha  DISCUSSION The  successful  e s t a b l i s h m e n t o f new  is  a necessary p r e r e q u i s i t e  and  other forest  United  States,  c r o p s on c u t o v e r  to sustained yield  (and w i l d l i f e )  resources.  approximately  22  million  In and  areas  o f wood  products  Canada  and  30  million  the ha  165  respectively,  require  artificial  Klinka  1977).  million  ha a n n u a l l y i n  reforestation up  on  the  With  regeneration  the present North  i s keeping  (Walters  rate of regeneration  America),  i t  is  backlog  of  lands.  I t h a s become e v i d e n t  forests  must be i n c r e a s e d a p p r e c i a b l y i f t h e f o r e s t  the  resources  Direct a  associated  seeding  practical  and  economical  Among  requirement  regeneration  of  stand  large  of  year  eating direct  germination  stocking the  than  Pacific  mainly  in  either  and a  developed  has  failed  America.  teen  a t a time  system  done  Why  as  a  Perhaps  one  failure  and  reliable of  autumn o r w i n t e r of  the  i s the time  how i t r e l a t e s t o and s e e d -  (1973) h a s r e p o r t e d t h a t t h e m a j o r i t y  However,  on t h e a v e r a g e  seeding.  of  higher  Similarly,  in  t h e U n i t e d S t a t e s , s e e d i n g h a s been  c a r r i e d out i n the f a l l  the f a l l  root  Canada h a s been done i n t h e f a l l .  Northwest  1958).  a r e lower  the a i r , f l e x i b i l i t y ,  Hay, and June has y i e l d e d  Lavender  problem o f  and p o p u l a t i o n s o f s m a l l mammals  Waldron  sowing i n A p r i l ,  offer  rapid  generally  i n North  seeding  seeding  seems t o  supervision,  problems a s s o c i a t e d with t h i s  birds*  maintained.  f o r seeding  and  man-made  i n d u s t r y and  a r e t o be  a naturally  has  practice  when  potential  from  of  t o t h e massive  f o r labour areas  restocked  1977).  seeding  most i m p o r t a n t  solution  o f t r e e s with  ( W a l t e r s and K l i n k a  reforestation  forests  the advantages c i t e d  c o s t , a lower  Direct  creation  i s a method o f r e g e n e r a t i o n w h i c h  reforestation.  resulting  with  the  that  or catching  unsatisfactorily  that  (about 1  unlikely  up w i t h t h e r a t e o f c u t t i n g  tremendous  and  (Gartz  h a s most d i r e c t  1955; C a r m i c h a e l seeding  when p o p u l a t i o n s o f d e e r  been  1957; and  attempted  in  m i c e , c h i p m u n k s , and  166  seed-eating the  b i r d s are  fall  undergoes by  able  germinate  to  soaking  stratification depredations  America,  successful, of  the  year  concluded likely  to  season  spring.  seed  from  being  and  winter.  few  (see C a r m i c h a e l  be  varied with  1957;  moisture  optimum  Spring  temperature  species,  to  other  mammal  be  more  (1973)  conditions  factors,  in  seasons  Arnott  However, the  site  then  programs  proved  1973).  for  i s  to small  at  in  laboratory  seeding  those  spring.  sown  and  However,  Saldron  and  i n the  tree  winter  exposed  with  seed  (preparation  i n number, have  when c o m p a r e d  that seedbed  the  the  although  at l e a s t  during  in  fall  conifer  stratification  i n water)  prevents  i n the  Presumably,  natural  germination  North  highest?  best and  were sowing  weather  patterns. Successful uniform A  distribution  uniform  tree  seedlings  clumped  or  because  i s  and  some  understocked. the  may  that  be  rows  whereas  a  more  likely  the  parts  This  stand of  raises along  planting  with  of  of  a  or  clearcut.  or  direct  trees  i s  done a f t e r  cutover  area  are  of r e f o r e s t a t i o n  predation  seedlings  of  random  scattered  must be  cost  a  methodically planting  result  the the  area  by  a  distribution  of  reguire  the  obtained  in  main r e a s o n s ,  mammals,  programs  seedlings over  aggregated  thinning  seeding  of  distribution  distribution  of  reforestation  i s now  of  seeds  favoured  random  seeding.  A  undesirable the  initial  obviously and  i s  one  by  small  over  direct  seeding. Another c r i t i c i s m seed  which  i s so  seed  that i s collected  of  direct  seeding  often i n short supply during  years  i s the  (Vyse  waste  1973).  w i t h a good  of  conifer  Presumably,  cone crop  should  167 be  used  i n production  shortages the  have  absence  However, is  wasteful  when  the  seeding  relatively  on r e l i e v i n g  resources  t h e seed  reforestation  of  seeding  new  reforestation  or  more  additional  the best  classes on of  the  has  work l o a d s task  of  1973).  sites  seeding,  planting  was f o u n d  ha  planting  are  The v a l u e  1977).  microsites,  supplies a  a search f o r  of having  one  reforestation  planting,  on a number o f t h e b e s t  economic,  in  Oregon)  site but  The a p p l i c a t i o n  and  administrative  in reforestation.  that p l a n t a t i o n s u r v i v a l B* C.  There  poor r e g e n e r a t i o n .  use  be  forcing  with  t o be i n f e r i o r .  growth  (Walters  species selection,  a given  t o the economic a n a l y s e s of  known f o r some time  seedling  as i n d i s c r i m i n a t e  per  may  and d w i n d l i n g  when compared  opportunity  a l l ecological,  responsible f o r this  planting  that i t  f o r successful  Recording  direct  been  subseguent  satisfactory  tree  philosophy  from n o t  c o n d i t i o n s i s n o t a s o u n d management a p p r o a c h  and  1S70).  ( i n t h e Douglas f i r r e g i o n o f southwestern  p l a n t i n g to  It  (Robinson  advantageous t o seed  saved  techniques  investment  poorer  Seed  reason f o r  l a r g e q u a n t i t i e s o f seed  (Vyse  c a n n o t be u n d e r e s t i m a t e d .  is  B. C-  i n addition to generating  methods  (1969),  planting.  shortage.  manpower f o r t h e a r d u o u s  Teeguarden  for  used t o grow s e e d l i n g s c o u l d r e s t o c k a much  the e x t r a  reappraisal  in  I f i ti s economically  Increased of  stock  (1973) d i s c u s s e s t h e e r r o n e o u s  same seed  a r e a , then  nursery  been o f f e r e d a s t h e p r i n c i p a l  direct  to apply  larger area.  spent  often  cf  Vyse  of  are  are  far  several  Non-ecosystem  from  factors specific  n o n - s e l e c t i v e management p r a c t i c e s s u c h of  and  slash poor  burning, quality  poor  selection  of  o f p l a n t i n g s t o c k and  168  planting  have a l l c o n t r i b u t e d  The  cost  o f n u r s e r i e s and p r o d u c t i o n  be  considered  when  to  analysing  the  problem  of seedling  the  problems  1577).  (Halters stock  must  associated  also sith  planting. Thus, t h i s c h a p t e r benefits  in  regenerating technique be  has  returning cutover  for  to  direct  forest  lands.  reducing  an i n t e g r a l p a r t  described  c o n i f e r seed  of the future  some  of  seeding The  the  as  means  biological  damage by d e e r  success  a  potential  of d i r e c t  mice  of  control should  seeding.  169  F i g u r e 5-1.  The s u c c e s s o f d i f f e r e n t  (and  ratios  oats)  at  two  and f o u r  Douglas  number o f s e e d l i n g s p e r ha a t  0-10  Douglas  f i r seed  c i r c l e s represent percentage 2-  The  line  connects  per  the average  open c i r c l e s r e p r e s e n t p e r c e n t a g e dashed  l i n e connects t h e average  a  density  shown.  o f Douglas  after  v a l u e s at each  The of  The c l o s e d  f i rafter  values at each  survival  sunflower  seeding-  seeding  ha i s a l s o  survival  to  weeks a f t e r  potential Kg  f i r  ratio.  week ratio.  4.  week The The  171  Figure  5.2.  Suggested  d i r e c t seeding with  procedure  conifer  seed  for successful and  alternative  reforestation foods.  by  172  Lowest d e n s i t y of Deer mice  Chipmunks and seede a t i n g b i r d s absent from c l e a r c u t s • f r o m l a t e October t o early A p r i l Lowest d e n s i t y i n Spring •  SUCCESSFUL STOCKING OF CLEARCUT  Mixture of c o n i f e r seed w i t h sunflower seed and o a t s i n 5 : 2 : 1 ratio — Uniform- d i s t r i b u t i o n over a r e a of clearcut:  173  LITERATUSE CITED  Abbott, H.G1973. D i r e c t seeding i n the United States. J.H. C a y f o r d ( e d . ) . D i r e c t s e e d i n g symposium. Dept., the Environment, Canad. ForSer., Put. No. 1339. 1-10. A h l g r e n , C.E. 1966. S m a l l mammals and prescribed burning. J. For. 64:  reforestation 614-618.  In: of pp.  following  Allen, G.S., I.K. Barber, and I. Mahood. 1955The a e r i a l b a i t i n g and s e e d i n g p r o j e c t , Ash Biver Tract, LtdFor. 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