WatchList Species Account for Willow Flycatcher (Empidonax traillii)

Qualifies for the list as a Declining Yellow List Species

Photo: © Ashok Khosla

The Willow Flycatcher is the most widely-distributed of the Empidonax flycatchers in North America and breeds in much of the U.S. save the southeastern and south-central states. It prefers shrubby, often wet habitats and in the more arid parts of its range it is restricted to river corridors. It migrates to southern Mexico, Central America, and as far south as Argentina. Its breeding range has expanded southward in the eastern U.S. and northward in southern Ontario, possibly at the expense of the closely-related Alder Flycatcher, but an endangered subspecies, the Southwestern Willow Flycatcher, has been extirpated from much of its range in California and Arizona, due to destruction of riparian habitats.

Breeding Bird Survey data show a decreasing trent for the U.S. of 1.2% a year, but there were significant increases in six states and sifnificant decreases in three. The Southwestern Willow Flycatcher, though much reduced in population in historic times, shows no evidence of recent declines. Habitat destruction and degradation and overgrazing by livestock pose threats to the species, as do damming, dredging, channelization, urban development, and water diversion have impacted this endangered subspecies, which, in addition, is heavily parasitized in some areas by Brown-headed Cowbirds. The survival of this subspecies will depend on maintaining and restoring riparian habitats.