The relation between age, body parameters and the stopover behaviour of a small, short-distance, migratory bird during the season of autumn (August.October) was studied. Capture-recapture data of 1018 first-year and 89 adult European Robins migrating through central Poland ("Kaliszany" ringing station, 21 [degree] 48'E, 51 [degree] 05'N) in autumn between 1997 and 2005 were analysed. Body mass, length of wing and tail of young Robins caught and stayed at the stopover site showed significant seasonal variation. Immature Robins made longer stopovers (median = 4 days, 1.41) in the area than older ones (median = 3 days, 1.32). The stopover duration decreased continuously during the season. However, body mass changes at the staging site was not related to the age of birds. The birds migrating in the second half of autumn (late September.October) period accumulated fat faster than birds migrating in the early season. Our analyses confirmed that late migrants stayed for shorter stopovers and gained more body mass than early migrating birds due to a shift in migration strategy as an adaptation to time stress.
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