Intermediate habitat associations by hybrids may facilitate genetic introgression in a songbird

Hybridization or the interbreeding of genetically discrete populations or species can occur where ranges of genetically distinct units overlap. Golden-winged warblers Vermivora chrysoptera, a species that has been in steady decline for decades, highlight the potential population-level consequences of hybridization. A major factor implicated in their decline is hybridization with their sister species, the blue-winged warbler Vermivora cyanoptera, which has likely been exacerbated by historic and current land-use practices. We examined habitat associations of golden-winged and blue-winged warblers, phenotypic hybrids, and cryptic hybrids (i.e. mismatch between plumage phenotype and genotype as identified by mitochondrial DNA) in an area of relatively recent range overlap and hybridization in northern New York, USA. To explore the robustness of these results, we then compared the patterns from New York with habitat associations from the central Pennsylvanian Appalachian Mountains where blu...

遗传分化的种群或物种间的杂交（即基因独立的种群与物种之间的交配）可发生于遗传特征迥异的类群分布范围重叠的区域。数十年来种群持续衰退的金翅虫森莺（Vermivora chrysoptera），凸显了杂交可能对种群产生的潜在影响。该物种种群衰退的主要诱因之一，是与姊妹种蓝翅虫森莺（Vermivora cyanoptera）的杂交，而历史与当前的土地利用方式可能进一步加剧了这一过程。我们在美国纽约州北部一处分布范围重叠与杂交事件均较新近发生的区域，分析了金翅虫森莺、蓝翅虫森莺、表型杂交个体以及隐秘杂交个体（即通过线粒体DNA（mitochondrial DNA）鉴定出的羽色表型与基因型不匹配的个体）的栖息地关联模式。为验证本研究结果的稳健性，我们将纽约州的相关分析结果与宾夕法尼亚州中部阿巴拉契亚山脉的栖息地关联模式进行了对比，该区域的相关研究中蓝翅[原文未完整呈现]