Weather and spring migration in birds

Some long-distance migratory birds have flexibly adapted to weather changes in recent decades by adjusting their timing of spring migration, a study finds. Populations of long-distance migratory birds are declining worldwide--a phenomenon thought to be driven by climate change, specifically the limited ability of long-distance migrants to advance their arrival timing at breeding grounds. However, data supporting the hypothesis is largely anecdotal and often contradictory. Birgen Haest and colleagues assessed the potential influence of weather variables on spring migration patterns for six species of cross-continental migratory birds that passed through the island of Helgoland, Germany between 1960 and 2014. Weather conditions at wintering grounds and spring stopover areas accounted for approximately 80% of interannual variation in spring migration patterns. Wind and temperature were both strongly influential in terms of explaining interannual variability in spring migration patterns. However, improvements in wind conditions were more important than rising temperatures in accounting for advancements in the timing of spring migrations over the 55-year period. Taken together, the results suggest that population declines for long-distance migratory birds are not likely due to an inability to advance the timing of spring migration in response to climate change. According to the authors, current evidence points toward anthropogenic land-use change as a major pathway by which climate change influences bird population sizes.

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Article #19-20448: "Weather at the winter and stopover areas determines spring migration onset, progress, and advancements in Afro-Palearctic migrant birds," by Birgen Haest, Ommo Hu?ppop, and Franz Bairlein.

MEDIA CONTACT: Birgen Haest, Institute of Avian Research, Wilhelmshaven, GERMANY; e-mail: birgen.haest@protonmail.com

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