Local adaptation from afar: migratory bird populations diverge in the initiation of reproductive timing while wintering in sympatry.

ABSTRACT: The initiation of reproduction in many seasonally breeding animals is controlled by photoperiod and tends to be clinal: populations at higher latitudes breed later than those at lower latitudes, often reflecting a higher photoperiodic threshold. Migratory animals presumably time reproduction to match conditions at their breeding grounds, at least in part, by cues perceived on their wintering grounds. We asked how closely related dark-eyed junco (Junco hyemalis) populations that overwinter in sympatry but breed in allopatry respond to their shared winter environment by comparing early spring indices of readiness to migrate (fat and muscle condition) and breed (baseline and elevated testosterone). We measured stable hydrogen isotopes from feathers grown the preceding year and claws gr

SUBMITTER: Wanamaker SM 

PROVIDER: S-EPMC7655480 | biostudies-literature | 2020 Oct

REPOSITORIES: biostudies-literature