Dissertation Research: A Multidimensional Analysis of Geographic Variation in the Plain Titmouse (Parus inornatus)

平原山雀（Parus inornatus）在北美西部的整个范围内，其整体大小，喙大小和颜色各不相同。根据形态和颜色，目前已经确认了十种地理形态（美国鸟类学家联盟，1957年，北美鸟类检查清单）。在喀斯喀特-内华达山脉西部，该物种通常发生在山麓橡树林地。在西南和山间地区密度较低，种群分布在小松或杜松生境中。本研究的目的是整合小舌舌鱼的形态、分子和行为数据，以阐明种群间分化的模式和过程。种群结构的差异将有助于测试基因流动的其他模型。关于适应和更新世隔离作用的假设也将被评估。各种现代系统技术将被用来检查形态和遗传变异的模式内和群体之间的小舌舌鱼。迄今为止的结果表明，在太平洋斜坡种群和山间种群之间存在很强的遗传分化，其程度与密切相关的鸟类物种之间的遗传分化相同。形态（尤其是喙的大小和形状）和颜色的变化模式支持遗传数据。基因流动的定量估计将有助于揭示种群间遗传和形态分化的过程。由于许多鸟类在太平洋斜坡和山间地区表现出相似的分化模式，这项研究将有助于形成北美西部鸟类物种的新图景。这项研究的结果可能会导致美国鸟类学家联盟委员会对分类和命名法进行正式的分类改革。鉴定遗传和/或形态上不同的种群将为有关保护和管理美国西部小松或橡树林地的管理人员提供关键信息。由于喀斯喀特-塞拉山麓、内华达山麓和海岸山脉的开发压力越来越大，加州橡树林地的未来日益受到关注。

The Plain Titmouse (Parus inornatus) varies in overall size, bill size, and color throughout its range in western North America. Ten geographic forms are currently recognized (American Ornithologists' Union, 1957, Check-list of North American Birds) on the basis of morphology and color. West of the Cascade-Sierra Nevada Mountains, the species occurs commonly in foothill oak woodland. Density is lower in the Southwest and Intermountain Regions, where populations are found patchily in pinyon-juniper or juniper habitat. The goal of this project is to integrate morphologic, molecular, and behavioral data on Parus inornatus in order to elucidate patterns and processes of divergence among populations. Differences in population structure will enable testing of alternative models of gene flow. Hypotheses concerning the role of adaptation and Pleistocene isolation also will be evaluated. A variety of modern systematic techniques will be used to examine patterns of morphologic and genetic variation within and among populations of Parus inornatus. Results to date indicate strong genetic differentiation between Pacific slope and Intermountain populations, on the order of that found between closely related species of birds. Patterns of variation in morphology (especially bill size and shape) and color support the genetic data. A quantitative estimate of gene flow will shed light on the process of genetic and morphologic divergence among populations. Because numerous bird species show similar patterns of divergence between the Pacific slope and Intermountain Regions, this study will contribute to an emerging picture of avian speciation in western North America. The results of this study will likely lead to formal taxonomic changes by the American Ornithologists' Union Committee on Classification and Nomenclature. The identification of genetically and/or morphologically distinct populations will provide critical information for managers concerned with the protection and management of pinyon-juniper or oak woodlands in the western United States. The future of oak woodlands in California is of growing concern because of increasing pressures for development in the foothills of the Cascade-Sierra, Nevada and Coast Ranges.