Brown-Headed Cowbird Nestling Vocalizations and Risk of Nest Predation

• DOI: 10.2307/4089378
• Publication Date: 2012-09-14T12:37:48Z
• Authors: Donald C. Dearborn
• Keywords: Cowbird; Begging; Bunting

Models concerning the evolution of avian begging behavior predict that nestlings brood parasites should beg more loudly or frequently than nonparasitic and exaggeration calls in general may be limited by risk nest predation. This study is first to test experimentally for a link between parasitism, nestling vocalizations, Begging at Indigo Bunting (Passerina cyanea) nests parasitized Brown-headed Cowbirds (Molothrus ater) were louder frequent those nonparasitized nests. Predation rates significantly higher during incubation period over entire nesting cycle, there was trend such difference as well. I performed an artificial experiment effect vocalizations on Nests broadcasting cowbird (300 calls/h 80 dB) experienced highest predation rates, followed bunting (60 74 dB), silent The overall among three treatments significant, but follow-up pairwise comparisons detected only Thus, partly responsible observed natural nests, other factors site parental are likely influence both parasitism