期刊论文详细信息
The Auk
Effects of Experimental Cowbird Removals on Brood Parasitism and Nest Predation in a Grassland Songbird
Karl L. Kosciuch1  Erin L. Hewett1  Brett K. Sandercock1 
关键词: Brown-headed Cowbird;    Dickcissel;    fecundity;    management;    Molothrus ater;    productivity;    Spiza americana;   
DOI  :  10.1525/auk.2008.06155
学科分类:动物科学
来源: Central Ornithology Publication Office
PDF
【 摘 要 】

Brood parasitism and predation are two factors that limit seasonal fecundity in grassland songbirds. We removed Brown-headed Cowbirds (Molothrus ater) in a switchback experiment to examine the effects of brood parasitism and nest predation on the productivity of Dickcissels (Spiza americana). Nesting Dickcissels were monitored at four study plots in northeast Kansas in a two-year study. Brown-headed Cowbirds were captured with drop-in traps at two removal plots, two unmanipulated plots were reference plots, and treatments were reversed between years. To evaluate the effect of Brown-headed Cowbird removals, we compared the percentage of nests parasitized, rates of multiple parasitism, clutch size, daily nest survival rates, and overall productivity per nest between removal and reference plots. Removals of Brown-headed Cowbirds successfully reduced the probability of parasitism and rates of multiple parasitism, but only in one of two years. Brown-headed Cowbirds did not appear to contribute to nest losses, given that few nests were abandoned because of cowbird activity and that the probabilities of nest parasitism and nest survival declined simultaneously over the breeding season. Overall, nest productivity showed no difference between treatments in either year, despite reduced rates of parasitism at removal plots in 2004. High rates of nest predation minimized the potential benefits of Brown-headed Cowbird removals for increasing productivity of Dickcissels. Our results demonstrate that removals can reduce parasitism levels but that the success of removal programs may vary annually, particularly in regions where Brown-headed Cowbirds and nest predators are abundant. Management actions that minimize parasitism and predation by modifying habitat structure may provide better alternatives to programs based on removals.

【 授权许可】

Unknown   

【 预 览 】
附件列表
Files Size Format View
RO201912050578086ZK.pdf 448KB PDF download
  文献评价指标  
  下载次数:12次 浏览次数:78次