Migratory behaviour constrains the phenological response of birds to climate change

摘要

Migratory birds may be unable to respond to climate change at their breeding groundsin the same way as residents because they do not experience local environmental conditions untilmigration has been completed, or because of limited plasticity in response to environmentalvariation. Indeed, several studies have shown that long-distance migrants have advanced theirphenology less than short-distance migrants in recent decades, suggesting a slower phenologicalresponse to ongoing climate warming. However, few studies compared the phenological response ofspecies that live year-round within the same climatic region (including residents) with that of speciesmigrating over longer distances. We used an extensive data set on temporal change in spring firstsinging date (FSD) during 1977-2006 of 56 resident and migratory bird species in Northern Germanyto test whether migratory status affected 2 aspects of the phenological response: the temporal trendin FSD and the response of FSD to local temperatures. Species migrating <4° latitude (ca. 450 km)(less migratory species) showed greater temporal advancement in FSD compared to more migratoryspecies. In addition, the variance in temporal trends was larger among less migratory species. Higherlocal temperatures were associated with earlier FSD, and multi-brooded species showed a strongeradvancement in FSD with higher temperatures than single-brooded species. However, the tempera-ture response was unaffected by migratory status, suggesting that the difference in the temporaltrend in FSD between less migratory and more migratory species was mainly due to climatic and/orenvironmental cues regulating departure of the latter from the wintering areas and/or temporalscheduling of migratory flights, rather than to differential responses of FSD to local temperatures.Therefore, migratory behaviour should be regarded as a life-history trait possibly constraining thephenological response to rapid climatic changes in avian species.