Spatial variation in avian bill size is associated with temperature extremes in a major radiation of Australian passerines

Morphology is integral to body temperature regulation. Recent advances in understanding of thermal physiology suggest a role of the avian bill in thermoregulation. To explore the adaptive significance of bill size for thermoregulation we characterized relationships between bill size and climate extremes. Most previous studies have focussed on climate means, ignoring extremes, and do not reflect thermoregulatory costs experienced over shorter time scales. Using 79 species (9,847 museum specimens), we explore how bill size variation is associated with temperature extremes in a large and diverse radiation of Australasian birds, Meliphagides. Overall, across the continent, bill size variation was associated with both climate extremes and means and was most strongly associated with winter temperatures; associations at the level of climate zones differed from continent-wide associations, were complex and non-linear, yet consistent with physiology and a thermoregulatory role for avian bills. W..., We used 79 species from the infraorder Meliphagides, the largest radiation of Australian passerines (formerly Meliphagoidea), to assess bill size patterns across geographic space and to test for associations between bill size and climate across the Australian continent., , # Spatial variation in avian bill size is associated with temperature extremes in a major radiation of Australian passerines

Kalya Subasinghe, Matthew R.E. Symonds, Suzanne M. Prober, Timothée Bonnet, Kristen J. Williams, Chris Ware, Janet L. Gardner

The data file contains variables in the analysis.

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# 澳洲雀形目大型演化支系的鸟类喙部尺寸空间变异与极端气温显著相关

形态学特征是体温调节过程中不可或缺的一环。近年来热生理学领域的研究进展揭示，鸟类喙部在体温调节中具有重要功能。为探究喙部尺寸在体温调节中的适应性意义，本研究系统分析了喙部尺寸与极端气候之间的关联。既往多数研究仅关注气候平均状态，忽略了极端气候条件，且未能反映短时间尺度下的体温调节能耗。本研究依托79个物种（共计9847号馆藏标本），针对澳大拉西亚鸟类的大型多样演化支系——吸蜜鸟下目（Meliphagides），探究了其喙部尺寸变异与极端气温之间的关联模式。整体而言，在整个澳洲大陆范围内，喙部尺寸变异同时与极端气候和气候平均状态相关，且与冬季气温的关联最为显著；不同气候区的关联模式与大陆尺度的关联模式存在显著差异，其关系复杂且呈非线性，但符合生理学规律与鸟类喙部的体温调节功能假说。（前文内容存在截断）本研究选取澳洲雀形目最大演化支系——吸蜜鸟下目（Meliphagides，原分类学名称为Meliphagoidea）下的79个物种，旨在刻画喙部尺寸的地理分布格局，并检验澳洲大陆范围内喙部尺寸与气候要素之间的关联。

Kalya Subasinghe, Matthew R.E. Symonds, Suzanne M. Prober, Timothée Bonnet, Kristen J. Williams, Chris Ware, Janet L. Gardner

本数据集文件包含本次分析所使用的全部变量。

| 变量 | 变量描述 |
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