Terrestrial species can respond to a warming climate in multiple ways, including shifting in space (via latitude or elevation) and time (via phenology). Evidence for such shifts is often assessed independent of other temperature-tracking mechanisms; critically, no study has compared shifts across all three spatiotemporal dimensions. Here we used two continental-scale monitoring databases to estimate trends in the breeding latitude (311 species), elevation (251 species) and phenology (111 species) of North American landbirds over 27 years, with a shared pool of 102 species. We measured the magnitude of shifts and compared them relative to average regional warming (that is, shift ratios). Species shifted poleward (1.1 km per year, mean shift ratio 11%) and to higher elevations (1.2 m per year, mean shift ratio 17%), while also shifting their breeding phenology earlier (0.08 days per year, mean shift ratio 28%). These general trends belied substantial variation among species, with some species shifting faster than climate, whereas others shifted more slowly or in the opposite direction. Across the three dimensions (n = 102), birds cumulatively tracked temperature at 33% of current warming rates, 64% of which was driven by advances in breeding phenology as opposed to geographical shifts. A narrow focus on spatial dimensions of climate tracking may underestimate the responses of birds to climate change; phenological shifts may offer an alternative for birds—and probably other organisms—to conserve their thermal niche in a warming world.

陆地物种可以通过多种方式对气候变暖做出反应，包括空间（通过纬度或海拔）和时间（通过物候）的变化。这种变化的证据通常独立于其他温度跟踪机制进行评估;至关重要的是，没有研究比较所有三个时空维度的变化。在这里，我们使用了两个大陆尺度的监测数据库来估计北美陆鸟在 27 年内的繁殖纬度（311 种）、海拔（251 种）和物候（111 种）的趋势，共享 102 种。我们测量了变化的幅度，并将其与平均区域变暖（即变化比率）进行了比较。物种向极地移动（每年 1.1 公里，平均转移率 11%）和向更高的海拔地区移动（每年 1.2 米，平均转移率 17%），同时也提前转移了它们的繁殖物候（每年 0.08 天，平均转移率 28%）。这些总体趋势掩盖了物种之间的巨大差异，一些物种的变化速度比气候快，而另一些物种的变化则更慢或方向相反。在三个维度 （n = 102） 中，鸟类以当前变暖速率的 33% 累计跟踪温度，其中 64% 是由繁殖物候学的进步驱动的，而不是地理变化。狭隘地关注气候跟踪的空间维度可能会低估鸟类对气候变化的反应;物候变化可能为鸟类（可能还有其他生物）提供另一种选择，以在变暖的世界中保护它们的热生态位。