The Acadian Flycatcher or Green-crested Flycatcher (Empidonax virescens) is a species of bird that breeds in deciduous forests across eastern United States and southwestern Ontario, Canada. They are migratory and winter through eastern Mexico and the Caribbean and south to southern Central America and northwestern South America (Colombia, Ecuador, and western Venezuela). In the southern parts of its breeding range these birds have declined in numbers.
The adult has olive colored upperparts, darker on the wings and tail. The underparts are whitish. It has a white eye ring, white wing bars and a wide bill. The breast has some olive coloring. The upper part of the bill is dark and the lower part is yellowish. The song is an explosive peet-sa. The call is a soft peet. They also have a call similar to that of the Northern Flicker.
The Acadian Flycatcher waits perched in the middle of a tree and flies out to catch insects in flight. It also will pick insects from foliage while hovering. They will also feed on berries and seeds. The nest is a loose cup built in a horizontal fork in a tree or shrub.
Brown-headed Cowbirds lay eggs in the nests of these birds in some areas.