Tyrant-flycatchers (Tyrannidae)

Willow Flycatcher (Empidonax traillii) - HBW 9, p. 360

French: Moucherolle des saules German: Weidenschnäppertyrann Spanish: Mosquero Saucero
Other common names: Traill’s Flycatcher

Taxonomy: Muscicapa traillii Audubon, 1828, Arkansas River, USA.
Formerly considered conspecific with E. alnorum. Geographical variation in plumage, wing morphology and vocalizations probably clinal, becoming browner overall in W and paler in more arid environments, and racial boundaries not well defined; sometimes treated as monotypic. Described race campestris (from North Dakota, in N USA) synonymized with nominate. Four subspecies currently recognized.

Subspecies and Distribution:

  • adastus Oberholser, 1932 - breeds SW Canada (S British Columbia) S in USA to E California (E of Sierra Nevada) and in Great Basin and Rockies; winters probably mainly W Mexico S to Panama.
  • traillii (Audubon, 1828) - breeds S parts of Canada (Alberta, Saskatchewan, Ontario, Quebec) and NC & NE USA; winters SW Mexico S to Panama and possibly extreme NW Colombia, also rarely to NE Ecuador.
  • brewsteri Oberholser, 1918 - breeds extreme SW Canada (SW British Columbia) S, W of Cascades, to SW California (W of Sierra Nevada); winters probably mainly W Mexico S to Panama.
  • extimus A. R. Phillips, 1948 - breeds SW USA; presumably winters W Mexico.