Ecophysiological constraints shape autumn migratory response to climate change in the North American field sparrow.

ABSTRACT: Our ability to accurately forecast species' geographical responses to climate change requires knowledge of the proximate and ultimate drivers of their distribution. Here, we consider the ecophysiological and demographic determinants of the distribution of a partial migrant, the North American field sparrow, Spizella pusilla. From 1940 to 1963, the field sparrow extended its winter northern range margin 222 km polewards. Such expansion was coincident with not only a geographical expansion into suitable breeding habitats, but also a decrease in mean abundance across sites occupied during the winter surveys. Combined, these trends suggest that declining populations along the expansion front either stopped migrating or altered their autumn migration. The poleward expansion was not coincident w

SUBMITTER: Monahan WB 

PROVIDER: S-EPMC2610066 | biostudies-literature | 2008 Oct

REPOSITORIES: biostudies-literature