5.75 inches long. The Acadian Flycatcher is a small flycatcher with a relatively heavy wide-based bill. The eye-ring is distinct with a whitish or yellowish-white color. It usually appears relatively flat-headed with a distinct peak on the rear crown. In breeding plumage the upperparts are greenish olive from crown to rump. It is very pale below. The throat is usually white. There is a faint olive breast-band and a faint yellowish wash on belly. There are white wing bars in the adults. The wing bars are buffy in the fall. The Acadian Flycatcher is a relatively large, long-winged Empidonax characterized by especially long primary extension. The bill is the longest and broadest of any Empidonax . This is one of five small “Empids” (Empidonax Flycatchers) that may show up in the Forest. It is best identified by its call. Differences in plumage due to molt, wear and age make the plumage quite variable. It is larger than Yellow-bellied Flycatcher (Empidonax flaviventris) and Least Flycatcher (Empidonax minimus). Its color shows greener upperparts and yellower underparts than all but the Yellow-bellied. The Yellow-bellied Flycatcher is usually more yellow underneath-especially on the throat, is smaller and more active, and has a smaller bill. Alder Flycatchers (Empidonax alnorum) and Willow Flycatchers (Empidonax traillii) are browner above and whiter below with less obvious eye rings. The Least Flycatcher (Empidonax minimus) is smaller, grayer above and whiter below and has a smaller bill.