The predatory behavior of wintering Emphasis Type

Authors: Timothy C Roth Steven L Lima

Publish Date: 2007/01/10

Volume: 152, Issue: 1, Pages: 169-178

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Abstract

Studies focused on how prey tradeoff predation and starvation risk are prevalent in behavioral ecology However our current understanding of these tradeoffs is limited in one key respect we know little about the behavior of predators In this study we provide some of the first detailed information on temporal patterns in the daily hunting behavior of birdeating Accipiter hawks and relate that to their prey During the winters of 1999–2004 twentyone sharpshinned hawks A striatus and ten Cooper’s hawks A cooperii were intensively radio tracked in rural and urban habitats in western Indiana USA Cooper’s hawks left roost before sunrise and usually returned to roost around sunset while sharpshinned hawks left roost at sunrise or later and returned to roost well before sunset An overall measure of Cooper’shawkinduced risk a composite variable of attack rate and activity patterns generally reflected the timing of prey activity with peaks occurring around sunrise and sunset In contrast risk induced by the smaller sharpshinned hawk did not strongly reflect the activity of their prey Specifically an early morning peak in prey activity did not correspond to a period with intense hawk activity The lack of early morning hunting by sharpshinned hawks may reflect the high risk of owlinduced predation experienced by these hawks The net effect of this intraguild predation may be to “free” small birds from much hawkinduced predation risk prior to sunrise This realization presents an alternative to energetics as an explanation for the early morning peak in small bird activity during the winterWe thank Bill Vetter Trey Franklin and our many field technicians for their assistance with hawk tracking Mike Russell provided assistance with information on owl diet We would also like to thank local businesses land owners especially M Evrard J Irwin C Martin and C Miller and the Terre Haute Parks Department for their cooperation John Castrale Burt Kotler Peter Scott and anonymous reviewers provided helpful comments on drafts of this paper This research was supported in part by the National Science Foundation grant IBN0130758 the Indiana Academy of Sciences and the Indiana State University Department of Ecology and Organismal Biology and School of Graduate Studies This research adhered to guidelines for the use of animals in research was reviewed and approved by the Institutional Animal Care and Use Committee at Indiana State University and followed all federal and state regulations for the collection and marking of wild animals

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