Willow Flycatchers are virtually impossible to distinguish in the field from their cousin the Alder Flycatcher except when they are vocalizing. The Willow Flycatcher song is a distinctive if undistinguished and sharp two syllabled "RITZ-bew" clearly enunciated although with a buzzy and sneezy quality to it. After breeding and during southward migration, most flycatchers dont say a word, making the many species in the genus Empidonax one of the most confusing puzzles in bird identification.
Western Willows are brownish overall but may also show shades of grey. A white throat and a slight but noticeable peaked crown may help separate this species from other flycatchers.
Willow Flycatchers are always closely associated with riparian habitats during breeding season. In Whistler they are fairly common in the valleybottom riparian thickets along the upper Soo River valley. This bird likes dense thickets of willow and red alder close to streams and ponds and makes a living by sallying for flying insects.
Although the Willow Flycatcher almost certainly nests in Whistler, no nest with eggs or young has ever been reported from the area. The Willow Flycatcher has undergone a well documented eastward range expansion within B.C. since about 1950. A slight northward range expansion during the same time would help explain why Whistler ornithologist Ken Racey did not note this species in the first half of the 1900s. It hadnt arrived yet.
The fate of this species in other parts of its range should make it a species of special concern in Whistler. The Willow Flycatcher has declined sharply across the Great Plains and the Pacific Coast. It has been nearly wiped out of California. According to Birds of B.C.: "Two reasons suggested for the decline are the alteration and loss of riparian habitat and Brown-headed Cowbird parasitism. These can be interactive, as a host species relegated to marginal habitats may become more vulnerable to its parasites and predators."
The continuing alteration and loss of riparian habitats in the area makes the Willow Flycatcher a species to watch in Whistler.
March 3 Monthly Bird Walk . Meet at the base of Lorimer Road at 8:00 a.m. Contact Michael Thompson (932-5010) for more information.
Sightings and Memberships: NatureSpeak is prepared by the Whistler Naturalists. To become a member or to report noteworthy sightings of mammals, birds, or other species, contact Lee Edwards (905-6448; e-mail: email@example.com).