Small flycatcher with a big, peaked head and relatively long bill. Extremely similar to several other species, especially Alder and Willow Flycatchers. Greenish-olive above and pale whitish below. Thin white eyering. Dark wings with distinct white wingbars. Very long wingtips. Best distinguished from other flycatchers by habitat and voice. Birds near the northern end of range prefer shaded ravines with mix of hemlocks and deciduous trees; farther south, found in mature deciduous forests. Tends to stay high in the canopy. Song is an explosive "pwit-SIP;" call note is a sharp "pweek."