Study Species

To learn more about how the environment affects the reproductive success of migratory birds, researchers have been studying Black-throated Blue Warblers (Dendroica caerulescens) breeding at the Hubbard Brook Experimental Forest in New Hampshire. These birds are long-distance migrants, splitting the year between breeding grounds in the U.S. and Canada and wintering grounds in and around the Caribbean. Each spring, they fly north to breed in the forests of the northeastern U.S. and southeastern Canada and along higher elevation areas in the Appalachian Mountains. Across their breeding range they favor deciduous and mixed deciduous-coniferous forests, where they build their nests in the shrubby understory.

These warblers are an excellent species to study because it is fairly easy to watch their behavior, find their nests, and monitor their breeding success. Also, their populations are not declining (luckily, this species tolerates some logging and other disturbances in its breeding and wintering habitat). Yet the factors that affect the reproductive success of Black-throated Blue Warblers are likely to apply to many other species whose populations are smaller and harder to observe. In fact, research on this species has already taught scientists a lot about how populations are limited and regulated, and how migratory birds might respond to climate change.