Les hommes ont oublié cette vérité. Mais tu ne dois pas l'oublier, dit le renard. Tu deviens responsable pour toujours de ce que tu as apprivoisé.
Le Petit Prince, chap. 21

Thursday, 6 December 2012

Cats predation and winter shortages for raptor prey

George, W.G.. 1974. Domestic cats as predators and factors in winter shortages of raptor prey. The Wilson Bulletin 86(4):384-396.

The  reader  who  has  digested  my  findings  can  imagine  that  a hawk  visiting my  study  site  in  the  winters  of  1968-1971  was  more  apt  to  see a  cat  than  a rodent

A  continuous  study  of  predation  by  three  rural  cats  was  conducted  in  Union  County, southern  Illinois,  from  1  January  1968  through  31  December  1971.  The  results  established  a  basis  for  examining  the  possibility  that  cat  predation  may  result  in  depleted winter  populations  of  microtine  rodents  and  other  prey  of  Red-tailed  Hawks,  Marsh Hawks,  and  American  Kestrels. 
Although  one of  the  three  cats never  ate  prey  and  each cat  was  assured  an  ample  supply  of  daily  food  at  home,  all  captured  prey.  Their  combined  predation  removed  an annual  average  of  483.5  vertebrates  and  286.4  mammalian  fetuses  from  a  combined  home range  of  22  acres  of  field  habitat  and  three  acres  of  woods.  By  volume,  the  principal prey  were  non-adult  cottontails,  by  frequency  of  captures,  prairie  voles.  Rodents  of seven  species  constituted  81.9  percent  of  the  total  combined  diurnal-crepuscular- nocturnal  catch,  and  over  95  percent  of  the  crepuscular-nocturnal  catch. 
The  cats  obtained  92.6  percent  of  their  average  annual  diurnal  captures  between  1 March  and  30  November.  Their  hunting  sucess in  winter  was  very  poor,  probably  as a  result  of  prey  shortages that  their  own  prior  predation  may  have  helped  create.  It  is suggested  that  when  captures  of  preferred  prey  by  skillful,  experienced  cats  on  their natal  hunting  grounds  sharply  decline,  the  home  range  of  the  cats  contains  few  such prey  for rodent-seeking  hawks. 

No comments:

Post a Comment

Related Posts Plugin for WordPress, Blogger...