Alder Flycatcher    Empidonax alnorum

Migratory Status: Neotropical migrant

PIF Population Estimate: 50 000 000

Percent of western hemisphere population breeding in boreal forest: 63%

BAM Effective Detection Radius (m) : 74.74

PIF Maximum Detection Distance (m) : 125

Canadian BBS Population trend: -0.3 n.s. (-0.8 to 0.2)

Life History

Until 1973, the Alder (E. alnorum) and Willow Flycatchers (E. traillii) were considered to be one species, the Traill’s Flycatcher, though recent genetic work has shown them to be distinct. As the two species are virtually identical in the field or in the hand, the only way to positively identify individuals is by song. Each has only one song type; the Alder Flycatcher’s song has a strongly accented second syllable and sounds like “fee-BEE-oo” or “free-BEER”, while the Willow Flycatcher’s song has an accented first syllable and sounds like “FITZ-bew”.

Due to the difficulty in separating the two species in the field, very little of the general ecology of the former “Traill’s” flycatcher can be ascribed to the Alder Flycatcher. The Alder Flycatcher has a more northernly breeding range, and is a common bird of wetlands and young regenerating deciduous stands in the boreal forest. The northern limit of its breeding range extends from Alaska, eastward across the boreal forest to Newfoundland and Labrador. Southward, its breeding range extends into the Great Lakes Region of the northern United States, and just into the southern parts of British Columbia and the Prairie Provinces in Canada. Along the southern edge it may overlap with the Willow Flycatcher, but the Alder is generally found at higher elevations and in wetter habitats. The winter range is unknown but the species is believed to overwinter in northern South America.

The Alder is a small flycatcher that is similar in appearance to many other members of the genus Empidonax. Males and females look alike, with olive-brown upperparts, a slightly darker crown, and a brown breast band that contrasts against a white throat. They have a medium to long tail, two white wingbars, and a thin eye-ring may be present. The bill is long and wide, with a darker upper mandible. The feet and legs are also dark.

The Alder Flycatcher feeds mostly on insects during the breeding season. Perching between 3 to 4 m off the ground, it takes short sallies and hawks the insect from the air or gleans them from foliage in surrounding trees and shrubs. During the winter, fruit becomes a minor component of the diet.

Reference(s)

Lowther, P. E. 1999. Alder Flycatcher (Empidonax alnorum), The Birds of North America Online, . A. Poole, Ed. Ithaca: Cornell Laboratory of Ornithology; Retrieved from The Birds of North America Online database: http://bna.birds.cornell.edu/bna/species/446