A growing body of evidence indicates that vocalizations of predators and perceived risk of predation can significantly alter avian nesting behavior and reproductive performance. However, it is currently unclear whether birds acoustically discriminate among different types of predators and adjust their short-term behavioral responses accordingly. We investigated this issue via playback experiments in which nests of the Hooded Warbler (Setophaga citrina) were exposed to vocalizations of two nest predators, the Blue Jay (Cyanocitta cristata) and Eastern Chipmunk (Tamias striatus), and a dangerous predator of adults and nestlings, Cooper's Hawk (Accipiter cooperii). We used songs of a common nonpredatory passerine, the Red-eyed Vireo (Vireo olivaceus), as a control. In comparison to responses observed during control trials, adult Hooded Warblers delayed their return to the nest following playback of Cooper's Hawk but returned more quickly after playback of the Eastern Chipmunk, probably because Cooper's Hawks are a threat to adult Hooded Warblers while Eastern Chipmunks pose a risk only to eggs and nestlings. Time of return to the nest following playback of the Blue Jay was nearly identical to that after controls, possibly because of the relative rarity of Blue Jays in our study area. Despite its significant effect on return time, playback had no effect on the number of times adults fed nestlings in the following hour. Overall, our results suggest that nesting Hooded Warblers discriminate among the vocalizations of potential predators and adjust the time of return to their nest according to the nature and degree of perceived risk.
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1 November 2012
Predator Vocalizations Alter Parental Return Time at Nests of the Hooded Warbler
Kasey M. Schaef,
Ronald L. Mumme
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The Condor
Vol. 114 • No. 4
November 2012
Vol. 114 • No. 4
November 2012
Blue Jay
Cooper's Hawk
Eastern Chipmunk
Hooded Warbler
playback experiment
predator vocalizations
Setophaga citrina