Habitat selection and migratory connectivity of a Neotropical migrant songbird

Addressing population declines in Neotropical migratory birds requires information on breeding demography and connectivity throughout the annual cycle. For species breeding in North American riparian habitats, anthropogenic changes to breeding habitat and indirect carry-over effects from the previous winter can both influence demographic rates. I examined whether a human-altered floodplain was an ecological trap by assessing habitat preferences and their reproductive consequences for yellow warblers (Dendroica petechia). I found that male settlement patterns were positively related to habitat cues that predicted breeding productivity, suggesting that extant riparian habitat was not attracting birds to poor quality sites. I then used stable hydrogen isotopes (D) to show that warblers moulted some feather blocks on breeding grounds and others during their tropical overwintering period. Assignment tests using D values in winter-grown feathers showed that most individuals originated from regions throughout Central America. However, interannual variation in isotope signatures limited further assignment accuracy.