Population structure and habitat use by overwintering neotropical migrants on a remote oceanic island

摘要: Abstract We studied habitat use by migrant birds on the island of San Salvador using mist nets during January 4 years (1997–2000). Information capture rates, body mass, age-sex class distribution, frequency recapture, and return rate were used to determine preferences for early successional habitat, mangrove, scrub or secondary forest. captured 23 species (19 parulid warblers), but focused our attention 14 most abundant (750 individually marked birds). A group four exhibited equal sex ratios, a female bias existed among common uncommon [e.g. black-throated blue warblers (Dendroica caerulescens) American redstarts (Setophaga ruticilla)]. Twelve habitats unevenly. Habitat also varied with age–sex in prairie (D. discolor) redstarts: both, males forests females habitat. Palm showed high variability years. Body mass did not vary species, more stressful conditions late dry season might reveal differences. Return rates significantly lower than estimates obtained same elsewhere Caribbean Central America, little identifying preferred habitats. However, recaptures (within between seasons) made where highest. Interspecific differences thus indicative preferences. Based this criterion, six Every however, was heavily at least three species. These latter findings, sex- age-specific patterns segregation, emphasize importance maintaining diversity conservation neotropical migrants.