Effects of supplemental food on parental-care strategies and juvenile survival of northern goshawks

Published source details Dewey S.R. & Kennedy P.L. (2001) Effects of supplemental food on parental-care strategies and juvenile survival of northern goshawks. The Auk, 118, 352-365.
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This study is summarised as evidence for the following.

	Action	Category
	Provide supplementary food for raptors to increase adult survival Action Link
	Provide supplementary food for raptors to increase reproductive success Action Link

Provide supplementary food for raptors to increase adult survival

A randomised, replicated and controlled trial in mixed conifer forests in Utah, USA, in 1996-7 (Dewey & Kennedy 2001), found that northern goshawk Accipiter gentilis females from territories provided with supplementary food (Japanese quail Coturnix japonica provided from close to hatching to chick independence) were significantly heavier than those from control (unfed) territories (1,104 g for eight fed females vs. 993 g for nine controls). This study also examined differences in chick growth and survival, discussed in ‘Provide supplementary food to increase reproductive success’.
Provide supplementary food for raptors to increase reproductive success

A randomised, replicated and controlled trial in mixed conifer forests in Utah, USA, in 1996-7 (8), found that northern goshawks Accipiter gentilis chicks from territories provided with supplementary food (Japanese quail Coturnix japonica provided from close to hatching to chick independence) were significantly heavier (although not larger) than those from control (unfed) territories (average of 778 g for 29 fed chicks vs. 723 g for 22 controls). Nestling survival was significantly higher in fed nests in 1997 (100% survival of 19 fed chicks throughout the study vs. 56% survival of 18 controls) but not 1996 (87% survival of 15 fed chicks throughout the study vs. 89% survival of 18 controls). The authors suggest this difference is due to variations in natural food supply as predation was not a primary mortality factor (although females did stay closer to nests in fed territories, compared to controls). This study also examined differences in adult female weights whilst provisioning, discussed in ‘Provide supplementary food to increase reproductive success’.