Temperature-associated Dynamics of Songbird Winter Distribution and Abundances

Butler, J. Russell
MacMynowski, Dena P.
Laurent, Chad
Root, Terry L.
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Using Christmas Bird Count data, we analyze the annual spatio-temporal abundances of six passerine species in the upper Great Plains, US (1960-1990). This study provides new insight into how global warming could cause separation of species within present-day communities. We find that winter relative abundances of similarly-sized songbirds are differentially affected by ambient winter temperature. As such, average annual winter temperature fluctuations (i.e., severity of winter) are significantly (P < 0.05) correlated with the relative abundances of three species while the other three are not. Our conditional probability-of-occurrence analysis indicates that the abundances of the three temperature-associated species declined markedly below -4°C while the abundances of the other three species fluctuated little from 8°C to -16°C. We conclude that even in colder climates i) the winter distributions of some, but not all, songbirds are directly or indirectly limited by temperature; and ii) these birds have dynamic abundances that can quickly respond to temperature changes.
Butler, J. R., MacMynowski, D. P., Laurent, C., & Root, T. L. (2007). Temperature-associated dynamics of songbird winter distributions and abundances. Ambio, 657-660. https://doi.org/10.2307/25547833