A widely distributed breeder in the forested landscape of the eastern United States, the Acadian Flycatcher is readily detected by its distinctive tee-chup or peet-sah song. This is generally a species of mature deciduous forests, although it nests in conifers in appropriate habitats in both the Northeast and Southeast. It formerly nested, as far as is known, to southern New England, then became absent there, early in the 1900s, reestablishing, and perhaps expanding beyond, its former range since the mid- to late 1900s.
Usually associated with water and found in bottomland forests, along small and large streams, this flycatcher has a characteristic shallow, flimsy-appearing nest with streamers of catkins hang-ing below. The nest is placed, hammocklike, in a fork of the lower branches of a small tree, generally 4-7 meters above the ground. The female does all of the nest-building, incubating and brooding; both sexes feed nestlings. A small percentage of successful pairs attempt second broods, particularly in the southern portion of the range.
Little information is available on food preferences of this species, but it forages on insects and other arthropods, particularly on the undersurfaces of leaves. It employs both gleaning and sally-hovering while foraging, but also captures insects in the air and occasionally on the ground. Acadians undergo a complete molt on the breeding grounds prior to fall migration.
Breeding Bird Survey data suggest that populations of the Acadian Flycatcher are relatively stable, although the species is area-dependent and sensitive to forest fragmentation. It experiences high rates of parasitism by Brown-headed Cowbirds and nest predation in small forest fragments, although levels of parasitism are usually lower than for other species of forest songbirds.
Although the Acadian Flycatcher is common and widely distributed and has been accorded a relatively high priority for management ( Probst and Thompson III 1996 ), it has not been studied extensively. Much of what is known about this bird derives from classic studies of natural history and breeding biology in Michigan ( Mumford 1964 , Walkinshaw 1966a ). In recent years much new information on breeding biology and the environ-mental factors influencing reproductive success has been obtained from studies in Indiana, Illin-ois, and Missouri (e.g., Greenberg 1993a , Robinson et al. 1995c , Winslow et al. 2000 ) and the Missis-sippi Valley ( Wilson and Cooper 1998 ). Much remains to be learned.