Avise's Birds of the World

Acadian Flycatcher
Empidonax virescens

Native Range: North America

Notes: this is another in a large group of small-sized Empidonax flycatchers that constitute a "sibling-species" complex, meaning that the species are nearly impossible to tell apart from one another in the field by plumage and morphology alone; instead, identification to a particular species relies on a combination of clues including habitat, subtle plumage features, behaviors in some cases, and especially the species' distinctive songs (which originally gave biologists the best hint that multiple species were present). This species of the eastern USA prefers tall deciduous woods, where it perches in the understory while waiting for insects to fly near enough fot it to catch with a short sortie. Song a rising exlosive spit-KEET.