A Ten-Year Study of the Stopover Patterns of Migratory Passerines during Fall Migration on Appledore Island, Maine

Abstract

This study examined the autumnal stopover patterns of migratory passerines on Appledore Island, Maine, from 1983 to 1992. We recaptured 13.4% of migratory passerines at least one day after initial capture with species averages ranging from 2.8% in Eastern Wood-Peewee (Contopus virens) to 33.5% in Philadelphia Vireos (Vireo philadelphicus). Most observed stopovers were less than four days. Young birds were more prevalent than adults in all species studied. Among Red-eyed Vireos (Vireo olivaceus), Black-and-white Warblers (Mniotilta varia), and Northern Waterthrushes (Seiurus noveboracensis) young birds were more likely to be recaptured than adults. Young Northern Waterthrushes had significantly longer stopovers than adults. No difference in recaptures was detected between the sexes in any species studied. Most of the birds captured were lean (fat class 0 or 0.5) at initial capture. In several species, young birds were significantly leaner both in terms offat class and mass than adults. Most species studied experienced significant increases in fat class and mass during stopovers. We did not find significant differences in mass or fat increases between age groups or between the sexes in any species studied. Cape May Warblers (Dendroica tigrina), Black-and-white Warbiers, and American Redstarts (Setophaga ruticilla) did not exhibit any differences in recaptures, stopover lengths, or mass increases among years. Northern Waterthrushes exhibited significant differences in recaptures and Red-eyed Vireos exhibited differences in recaptures and mass increases among years during this study.