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Goshawk Winter Ecology in Swedish Pheasant Habitats

Robert E. Kenward, Vidar Marcström and Mats Karlbom
The Journal of Wildlife Management
Vol. 45, No. 2 (Apr., 1981), pp. 397-408
Published by: Wiley on behalf of the Wildlife Society
DOI: 10.2307/3807921
Stable URL: http://www.jstor.org/stable/3807921
Page Count: 12
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Goshawk Winter Ecology in Swedish Pheasant Habitats
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Abstract

Predation and movements of 43 radio-tagged goshawks (Accipiter gentilis), including 6 adult males, 14 adult females, 16 juvenile males, and 7 juvenile females, were monitored in autumn and winter for up to 215 days/bird at 3 estates in central Sweden. Trapped adult males had less tendency to leave study areas than adult females, but juvenile males had the most tendency to leave. Movement away was not related to body weight at 1st capture. Initial ranges of juveniles were larger than those of adults. At an estate where 4,000 ring-necked pheasants (Phasianus colchicus) are released annually, hawk capture rates and density, hawk weights, and rate of predation on pheasants were greater, and ranges smaller, than at an estate with only wild pheasants. Goshawks were responsible for an estimated 88% of the 64% overwinter loss among female wild pheasants, and for 23% of the 76% loss among males. The predation showed no marked selection of pheasants in poor condition, but females were selected when the ground was covered with snow. When all kills probably were found, male goshawks ate 133 g/day and females 189 g/day. Wild pheasants accounted for an estimated 43% of the males' food, whereas European hares (Lepus capensis) comprised 37% of the diet of females. Red squirrels (Sciurus vulgaris) were the most frequently taken prey, and provided the 2nd largest prey biomass, 10-15%, for both hawk sexes.

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