A Distributional History of the Black-crested Titmouse
A Distributional History of the Black-crested Titmouse
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黑冠山雀的分布史
DOI：
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发表时间：
1978
期刊：
影响因子：
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通讯作者：
K. Dixon
中科院分区：
文献类型：
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作者：
K. Dixon
下面的叙述，由分布，古生物学和考古学数据的支持，是作为一个系统的解释的起源和现在出现的黑冠比赛的双色山雀。灰冠的祖先人口到达墨西哥东北部从得克萨斯州东部通过一个树木繁茂的沿海走廊在潮湿的条件下，在威斯康星州晚期的时间。最初的隔离与全新世早期大平原气候向德克萨斯州南部墨西哥湾沿岸的扩张相吻合。分化在荆棘林或相关的干旱热带生长的羽毛性状的衍生形式，促进视觉信号对春季植被背景是密集和浅灰色的建议。一旦适应了半干旱的环境，黑冠山雀就向西北方向的山麓或山地林地扩散到德克萨斯州西部的山区，然后向东扩散到德克萨斯州中部。松栎杜松林地的破碎化，导致分化较弱的亚种的隔离，不迟于4000年前与干旱的增加同时发生。与得克萨斯州中部的灰冠种群（簇绒山雀）杂交，证明物种形成的不完全性，可能是在那之后不久开始的。
The following account, supported by distributional, paleontological and archaeological data, is presented as a conjectural explanation of the origin and present occurrence of the black-crested races of Parus bicolor. Grey-crested ancestral populations reached northeastern Mexico from eastern Texas via a wooded coastal corridor under humid conditions in late Wisconsinian time. The initial isolation coincided with the early Holocene expansion of the Great Plains climate to the Gulf coast of southern Texas. Differentiation in thorn forest or related arid tropical growth is suggested by the plumage traits of the derived form which promote visual signalling against a vernal vegetational background that is dense and grayish. Once adapted to semiarid conditions, the black-crested titmice spread northwestward in foothill or montane woodlands to the mountains of western Texas, and thence eastward into central Texas. Fragmentation of pinyon-oak-juniper woodlands, leading to the isolation of weakly differentiated subspecies, occurred coincident with increasing aridity no later than 4000 years ago. Hybridization with the gray-crested populations (the tufted titmouse) in central Texas, demonstrating incompleteness of speciation, probably began soon afterward.