Wintering birds serve as vital climate sentinels, yet they are often overlooked in studies of avian diversity change. Here, we provide a continental‐scale characterization of change in multifaceted wintering avifauna and examine the effects of climate change on these dynamics. We reveal a strong functional reorganization of wintering bird communities marked by a north–south gradient in functional diversity change, along with a superimposed mild east–west gradient in trait composition change. Assemblages in the northern United States saw contractions of the functional space and increases in functional evenness and originality, while the southern United States saw smaller contractions of the functional space and stasis in evenness and originality. Shifts in functional diversity were underlined by significant reshuffling in trait composition, particularly pronounced in the western and northern United States. Finally, we find strong contributions of climate change to this functional reorganization, underscoring the importance of wintering birds in tracking climate change impacts on biodiversity.

中文翻译：

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北美越冬鸟类的功能重组

越冬鸟类是重要的气候哨兵，但在鸟类多样性变化的研究中它们经常被忽视。在这里，我们提供了多方面越冬鸟类变化的大陆尺度特征，并研究了气候变化对这些动态的影响。我们揭示了越冬鸟类群落的强烈功能重组，其特征是功能多样性变化的南北梯度，以及性状组成变化的温和的东西梯度。美国北部的组合出现了功能空间的收缩和功能均匀性和原创性的增加，而美国南部则看到了功能空间的较小收缩和均匀性和原创性的停滞。性状组成的显着重组凸显了功能多样性的变化，在美国西部和北部尤其明显。最后，我们发现气候变化对这种功能重组的巨大贡献，强调了越冬鸟类在跟踪气候变化对生物多样性影响方面的重要性。