Alder: Empidonax alnorum
Willow: Empidonax virescens
Order Passeriformes
Family Tyrannidae
Subfamily Fluvicolinae
Other names: Because it’s very hard to differentiate Alder and Willow flycatchers, some people refer to both of them as Traill’s Flycatcher. There are differences between them, so if we are sure in an ID, we’ll mention it in the picture.
Alder Flycatcher
Adult.— Upper parts dark olive-green, often with a tinge of brown; under parts white, washed with yellowish on the belly; wing-bars brownish-gray.
Nest, in crotch of small bush near the ground, made of coarser material than the Chebec’s.
Eggs, spotted.
The Alder Flycatcher has been found breeding in northern New Jersey, in northwestern Connecticut, and in eastern Massachusetts, but outside the Canadian Zone it occurs chiefly as a regular but rare migrant late in May or very early in June. From the edge of the Canadian area northward it is a rather common summer resident, frequenting alder thickets along streams and swampy places, as well as wet clearings and ill-drained hillsides.
Its song is like the syllables qui-dee’, ending with a marked ee instead of the sharp ic of the Chebec. The singer either mounts an exposed perch, where he may be seen jerking his head violently, or as often sings concealed in the leafy twigs. Where the birds are common, the song is heard as late as the first week in August, but it is not regular after the middle of July. The call-note is a sharp pip.
Its appearance in the field is so like the Least Flycatcher that only a very well-trained eye can distinguish the two species. The notes, however, of the two are very unlike; the marked difference in habitat, moreover, should make it comparatively easy to separate the two species in the breeding season.
Hoffmann – A Guide to the Birds of New England and Eastern New York (1904)