At one time, the Willow and Alder Flycatchers were considered to be a single species, the Traill's Flycatcher. The southwestern subspecies of this bird is declining due to habitat loss and is considered to be endangered. The Willow Flycatcher feeds by flying out from a perch, near the top of a shrub, and catching insects in flight. Insects are also picked from foliage while hovering. Berries are also sometimes consumed.
Olive-brown upperparts. The wings and tail are slightly darker. Whitish underparts. Olive wash on breast. Two (weak) whitish wing bars, buff colored on juveniles. Triangular shaped head. Dark upper mandible; pale orange lower mandible. Indistict eye ring not often visible. Sexes similar. 6 inches in length.
Deciduous thickets, especially willows, and often near water.
3-4 creamy-white eggs with fine brown speckling. They have an incubation period of 12-13 days. Fledging occurs 12-14 days after hatching. The nest is a compact open cup made from plant down and fibers. It is built in a low bush or sapling.