Willow Flycatcher

It impossible to discuss the Willow Flycatcher without reference to the closely related Alder Flycatcher, since for a long time they were not thought to be separate species. Studies of song led to the splitting of the then “Traill’s” Flycatcher in 1973, and to this day the only sure way to tell the two apart is by voice. Willow Flycatcher sings an emphatic “fitz-bew” with the stress on the first syllable, while the Alder’s song is a more subdued “fee-bee-o” with the stress on the second. By late summer birds have stopped singing, and birders need to revert to the old “Traill’s Flycatcher” catch-all when recording their observations.

Willow Flycatchers inhabit shrubby areas primarily south of the White Mountains, with recent expansion into the southern edge of Coos County. They tend to occupy drier areas than Alders, although both can occur in the same wetland. Willows are also more common than Alders at lower elevations such as near the seacoast in major river valleys.

Because they overlap across most of the Northeast and were considered the same species for a long time, getting conclusive data on Willow and Alder Flycatcher populations trends is complicated. Data from northern regions, where Willow is absent or rare, show declines that are presumably primarily in Alder Flycatcher, while increases to the south are probably more attributable to Willow. In the core of the overlap zone (mid-Atlantic states, New England) the two species together show an increase followed by a decrease. The New Hampshire trend is a slow and steady increase, which makes sense for Willow Flycatcher given its northward expansion in the state.