Timing is everything: seasonal comparison of migratory stopover
Timing is everything: seasonal comparison of migratory stopover.
MELISSA S. MUSTILLO, ELIZABETH H. LEWIS, KATHRYN E. MATTERN, SARA R. MORRIS and H. DAVID SHEETS, Dept. Biol. & Physics, Canisius Coll., Buffalo, NY.
Although migration is relatively widespread in birds, few studies have compared the two migratory seasons. Knowing that seasonal priorities of migrants may differ, the migration and stopover ecology of birds are also likely to differ between spring and fall. The goals of our project were to compare stopover ecology between spring and fall migration and to investigate possible annual variations. Using data from five species banded on Appledore Island, ME, we compared recapture rates and stopover lengths (both minimum and stopover duration analysis [SODA]) between the seasons. The recapture rate for most species analyzed was significantly higher during fall. The minimum stopover was also longer during fall. When each year's record of Red-eyed Vireo data was analyzed, there was a general pattern showing minimum stopover and SODA stopover to be longer during fall. Annual recapture rates for this species were also significantly higher during fall. It appears that there are seasonal differences in the stopover ecology of migrating birds. Birds have longer stopovers and higher rates of recapture during fall compared to spring. Our results are consistent with the hypothesis that avian behavior during spring migration is influenced by the need to arrive early on breeding grounds, while fall migrants are not time limited at this northern stopover site.