RUI: Experimental and Landscape Analyses of the Decline of a Neotropical Migrant

本研究将分析景观因素和干扰竞争对新热带候鸟金翅莺丰度的影响。这个物种已经减少，甚至从它的大部分活动范围消失了。这种减少被归因于繁殖栖息地的丧失，或与入侵同类的行为相互作用，或冬季栖息地的丧失。实地研究将确定金翅莺单独和蓝翅莺（V. pinus）共同使用的筑巢栖息地的营养特征。景观分析，利用当前和历史的航空照片，将评估筑巢栖息地的区域可用性的变化，并将与金翅莺丰度的变化相关联。将确定有或没有邻近蓝翅林莺的栖息地使用情况，以及实验性移除蓝翅林莺后使用情况的变化。筑巢成功将与蓝翅莺的接近程度和筑巢栖息地的营养特征有关。这些研究将有助于确定这两个同系物的共存是否更多地受到对特定栖息地的专门适应或它们的行为相互作用的限制。这些对繁殖季节的分析可能有助于了解冬季栖息地丧失的相对意义。鉴于全球气候和土地利用模式的快速变化，这些结果也可能具有更普遍的意义。

This research will analyze the effect of landscape factors and interference competition on the abundance of a neotropical migrant, the Golden-winged Warbler (Vermivora chrysoptera). This species has declined and even disappeared from a large portion of its range. This decline has been attributed to a loss of breeding habitat, or to behavioral interactions with an invading congener, or to a loss of winter habitat. Field studies will determine the vegetative characteristics of the nesting habitat used by the Golden-winged Warbler alone and in sympatry with the Blue-winged Warbler (V. pinus). Landscape analyses, utilizing current and historical aerial photographs, will assess changes in the regional availability of nesting habitat, and will be correlated with changes in Golden-winged Warbler abundance. Habitat use with and without neighboring Blue-winged Warblers, and changes in use following experimental removal of Blue-winged Warblers will be determined. Nesting success will be related to Blue-winged Warbler proximity and to vegetative characteristics of nesting habitat. These studies will help determine if coexistence of these two congeners is limited more by specialized adaptations to a particular habitat or by their behavioral interactions. These analyses of the breeding season may provide insight about the relative significance of winter habitat loss. The results may also be of more general significance in light of rapid changes in global Climate and land use patterns.