Brood parasitism of White-rumped Swallows by Shiny Cowbirds |
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Authors: | Viviana Massoni David W. Winkler Juan C. Reboreda |
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Affiliation: | Departamento de Ecología, Genética y Evolución, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabellón II, Ciudad Universitaria, C 1428 EHA, Buenos Aires, Argentina; Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York 14853 USA |
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Abstract: | ABSTRACT. Swallows and martins are infrequent hosts of the generalist brood parasite Shiny Cowbird ( Molothrus bonariensis ). We monitored 50 nesting attempts by White-rumped Swallows ( Tachycineta leucorrhoa ) over a two-year period in Argentina and detected low rates of brood parasitism (three nests, or 6%). Of the three nests parasitized, cowbirds ( N = 1 per nest) successfully fledged from two. Eight of 13 swallow eggs in these three nests were punctured by cowbirds, and all but one swallow nesting starved at the two parasitized nests. At least two factors may contribute to the low frequency of parasitism of White-rumped Swallows by Shiny Cowbirds, including the inability of the larger cowbirds to enter some nest cavities and the aggressive nest defense behavior of adult swallows. |
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Keywords: | brood parasitism Molothrus bonariensis Shiny Cowbird Tachycineta leucorrhoa White-rumped Swallow |
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