2025/10/01 by Rebecca J. Ralston, Christopher M. Tonra · 1 voice
Environmental Science · #Species Distribution and Climate Change #Remote Sensing in Agriculture #Fire effects on ecosystems
paper · pdf · doi:10.1111/ddi.70099
ABSTRACT Aim Climate change is broadly altering species’ phenology, and phenological asynchrony between birds and their required breeding resources can sharply decrease productivity. While some bird species have altered their spring migration timing, it is poorly understood why others have not. We examine how environmental conditions across the annual cycle influence arrival timing across the breeding distribution of one such species, the prothonotary warbler ( Protonotaria citrea ). Location The breeding distribution of the prothonotary warbler (eastern and central United States). Methods Using 11 years of eBird data, we modelled mean arrival dates across the breeding distribution of the species. We then fit generalized linear mixed models to assess how primary productivity of vegetation, average rainfall, and temperature on the nonbreeding grounds and spring stopover range, as well as vegetation phenology and temperature on the breeding grounds, influenced arrival timing. Additionally, we identified whether these relationships varied spatially across the distribution of the species while controlling for migration distance. Results Mean arrival of eastern prothonotary warblers was up to 7 days later in years with lower primary productivity of vegetation in March on the nonbreeding grounds. However, western populations showed no significant response to nonbreeding environmental conditions. Drivers of arrival timing did not vary according to migration distance but rather varied longitudinally. The impacts of stopover and breeding ground environmental conditions were minor compared to nonbreeding environmental conditions. Main Conclusions Climatic variation on the nonbreeding grounds can affect migration timing at broad scales. Eastern prothonotary warbler populations, which are declining, show greater evidence of carry‐over effects of nonbreeding environmental conditions than western populations, potentially due to differences in migratory strategy. Therefore, eastern populations may be more vulnerable to changing nonbreeding ground conditions, and such conditions may be a driver of the differential declines seen in the prothonotary warbler.