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Spring migration phenology of migratory birds has advanced under warming climate.Migration timing of short-distance migrants is believed to be responsive to environmental changes primarily under exogenous control.However,understanding the relative importance of endogenous and exogenous control during the entire annual migration cycle of birds is still a challenge.We tested the predictions of 1) the phenotypic plasticity hypothesis that the spring migration timing of individual American white pelicans (Pelecanus erythrorhynchos),a short-distance migrant,advances with increasing temperatures and has low repeatability;and 2) the early bird hypothesis that the mean spring departure date of P.erythrorhynchos advances over years,with high repeatability and early departures of recent recruits.