Do Nest Size and Shape Characteristics Affect Nest Parasitism Rates?

作者：Hackemack Taylor F^*; Loman Zachary G; Riffell Samuel K; Rush Scott A

来源：WILDLIFE SOCIETY BULLETIN, 2016, 40(4): 722-726.

DOI：10.1002/wsb.707

• brood parasitism
• brown-headed cowbird
• Mississippi
• Molothrus ater
• nest morphometrics
• scrub-successional birds
• songbird nesting

Brown-headed cowbirds (Molothrus ater) are obligate brood parasites that lay eggs in host species' nests. Studies on effects of host nest characteristics (e.g., nest placement, concealment, nest size) on parasitism rates by brown-headed cowbirds have yielded ambiguous results. To elucidate potential relationships between nest characteristics and brood parasitism rates, we collected data from indigo bunting (Passerina cyanea; n = 68), prairie warbler (Setophaga discolor; n = 30), and yellow-breasted chat (Icteria virens; n = 127) nests from early successional, managed loblolly pine (Pinus taeda) stands in Kemper County, Mississippi, USA, during 2012-2013. We recorded concealment, percent canopy cover, nest height (m), and nest morphometrics for each nest to test how these parameters related to frequency of brown-headed cowbird nest parasitism for each species. We predicted that larger, heavier nests would have an increased likelihood of parasitism. We recorded nest parasitism of 3%, 18%, and 24% for yellow-breasted chat, indigo bunting, and prairie warbler nests, respectively. Model coefficients for nest size did not differ from zero and nest size metrics did not differ between parasitized and unparasitized nests, thus contradicting our hypotheses and findings of previous studies relating nest size to parasitism. Our results suggest that the relationship between host nests and risk of brown-headed cowbird parasitism likely varies according to species of interest, geographic location, and features of available habitat.

• 出版日期2016-12