Argentina, Belize, Bolivia, Brazil, Canada, Colombia, Costa Rica, Cuba, Ecuador, El Salvador, Guatemala, Honduras, Mexico, Nicaragua, Panama, Peru, St Pierre and Miquelon (P), USA (B), Venezuela.
Breeds from western Alaska south to south-central British Columbia and east to Canadian Maritime Provinces, and from Great Lakes eastern in USA to New England and south to northern Indiana, Ohio and, in Appalachians, to North Carolina. Winters mainly western South America, from central Colombia and eastern Ecuador south to eastern Peru and northern and eastern Bolivia; probably also in eastern Panama and northern Argentina.
Population
Estimated population is 50,000,000 (2010).
Alder Flycatcher (Empidonax alnorum) [XC477364]
by Richard E. Webster from New York (near Ashville),Watts Flats Wildlife Management Area Chautauqua County, New York, United States (song)
Alder Flycatcher (Empidonax) [XC598804]
by Matt Wistrand from Hollis, Hillsborough County, New Hampshire, United States (song)
Subspecies
No subspecies.
Formerly considered conspecific with Willow Flycatcher (Empidonax traillii). Birds in north-west of range (Alaska, Yukon Territory and north-western Mackenzie) may average larger, with paler head and slightly paler back and named as subspecies alascensis, but further studies required.
BirdLife International Species Factsheet