Dissertation Research: Wood Thrush Population Regulation in a Fragmented Landscape

最近北美森林繁殖鸣禽的数量下降引起了人们越来越多的关注。这些物种在小森林地带的缺失引发了关于森林破碎化对鸣禽繁殖成功影响的问题。褐头牛鹂对巢的捕食和雏鸟寄生的增加似乎与森林破碎化的增加有关。然而，关于牛鹂寄生和巢捕食对森林筑巢鸟类个体繁殖成功的影响的数据缺乏。摘要本研究的目的是研究一种快速衰退的森林鸣禽——画眉鸟的种群动态。在伊利诺斯州南部的肖尼国家森林（Shawnee National Forest），在一个适度分散的地区，决定繁殖成功的因素将被研究，那里的牛鹂寄生率和巢捕食率很高。这些数据将用于评价一个种群动态模型，该模型提出一些种群（来源）经常产生多余的后代，这些后代移民到其他种群（汇），否则这些种群将由于繁殖成功率低而灭绝。该模式将在区域、地方和时间尺度上进行评价。

There is a growing concern about recent population declines in forest breeding songbirds in North America. The absence of many of these species from small forest tracts has led to questions about the effects of forest fragmentation on songbird reproductive success. Increased nest predation and brood parasitism by brown-headed cowbirds appear to be associated with increased forest fragmentation. There is, however, a paucity of data on the impact of cowbird parasitism and nest predation on the reproductive success of individual species of forest-nesting birds. The purpose of this study is to examine the population dynamics of the wood thrush, a rapidly declining forest songbird. The factors determining reproductive success on three study sites in a moderately fragmented region, the Shawnee National Forest of southern Illinois where cowbird parasitism and nest predation rates are high will be studied. These data will be used to evaluate a model of population dynamics that proposes that some populations (sources) regularly produce surplus offspring which immigrate to other populations (sinks) which would otherwise become extinct as a result of low reproductive success. This model will be evaluated at regional, local and temporal scales.