The Acadian Flycatcher or Green-crested Flycatcher, Empidonax virescens, is a small insect-eating bird of the tyrant flycatcher family.

Adults have olive upperparts, darker on the wings and tail, with whitish underparts; they have a white eye ring, white wing bars and a wide bill. The breast is washed with olive. The upper part of the bill is dark; the lower part is yellowish.

Their breeding habitat is deciduous forests, often near water, across the eastern United States and southwestern Ontario. They make a loose cup nest in a horizontal fork in a tree or shrub.

These birds migrate through eastern Mexico and the Caribbean, (where they are passage migrants), to southern Central America and the very northwest of South America, in the countries of Colombia, western Venezuela, and Ecuador.

They wait on a perch in the middle of a tree and fly out to catch insects in flight-(hawking), also sometimes picking insects from foliage while hovering-(gleaning). They may eat some berries and seeds.

This bird's 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 numbers of these birds have declined somewhat in the southern parts of their range. Brown-headed Cowbirds lay eggs in the nests of these birds in some areas.

Curiously, there are no official records of this bird walking.