About Empidonax virescens (Vieillot, 1818)
This species, the Acadian flycatcher (Empidonax virescens (Vieillot, 1818)), has the following physical characteristics. Adult birds have olive-colored upperparts that are darker on the wings and tail, paired with whitish underparts. They have a white eye ring, white wing bars, and a wide bill. The breast has an olive wash, the upper part of the bill is dark, and the lower part of the bill is yellowish. Body measurements for the species are: length 5.5–5.9 inches (14–15 cm), weight 0.4–0.5 ounces (11–14 g), and wingspan 8.7–9.1 inches (22–23 cm).
The Acadian flycatcher's song is an explosive peet-sa, and its common call is a soft peet. It also has a call similar to that of the northern flicker, and a unique two-note song described as "ka-zeep" that helps identify the species.
Its breeding habitat is deciduous forests, often located near water, across the eastern United States and southwestern Ontario. These birds migrate through eastern Mexico and the Caribbean to southern Central America and the far northwest of South America, including Colombia, western Venezuela, and Ecuador. As of October 2015, there are two recorded records of this species in Europe: the first was a bird found dead in Iceland in 1967, and the second was a bird found on the beach at Dungeness in Kent, England in September 2015, whose identity was confirmed via DNA from its droppings.
Population numbers of the Acadian flycatcher have declined somewhat in the southern portions of its range. In some areas, brown-headed cowbirds lay their eggs in Acadian flycatcher nests; however, only 16% of cowbird young raised in these nests fledge successfully.
For feeding, Acadian flycatchers wait on a perch in the middle of a tree and fly out to catch insects in flight (a behavior called hawking). They also sometimes pick insects from foliage while hovering (a behavior called gleaning), and they may eat some berries and seeds. They build loose, shallow nests in horizontal forks of trees and shrubs, mostly in lowland forests and marshy areas. The Acadian flycatcher is an excellent flier; it is extremely maneuverable, can hover, and can even fly backward. There is no published scientific information about whether this species hops or walks.
