Family Tyrant-flycatchers (Tyrannidae)

Least Concern

Pacific-slope Flycatcher (Empidonax difficilis)


French: Moucherolle côtier German: Feuchtwald-Schnäppertyrann Spanish: Mosquero del Pacífico
Other common names: Western Flycatcher (when grouped with E. occidentalis)

Empidonax difficilis

S. F. Baird

, 1858,

Fort Steilacoom, Washington, USA


See E. flaviventris (above). Formerly treated as conspecific with E. occidentalis; separated on grounds of differences in voice, morphology and allozymes, but this treatment questioned by some authorities#R; further study needed in contact zone in interior NW North America. Sometimes also considered conspecific with E. flavescens. Race insulicola (Channel Is) suggested in HBW as perhaps a separate species on basis of different morphology, voice, habitat use and genetics, but daytime song seemingly identical to that of mainland forms; further study needed. Three subspecies recognized.

Subspecies and Distribution
  • E. d. difficilis S. F. Baird, 1858 – SE Alaska S to S California (generally W of Sierra Nevada) and extreme NW Mexico (N Baja California); winters W Mexico (S to S Baja California, and from Sinaloa to Oaxaca).
  • E. d. insulicola Oberholser, 1897 – Channel Is, off S California (USA); winter range unknown.
  • E. d. cineritius Brewster, 1888 – Sierra de la Laguna (Victoria Mts), in Cape district (S Baja California).
  • Descriptive notes

    14–17 cm; 9–12 g. Large-headed flycatcher. Nominate race has indistinct pale supraloral line, distinct white to dull yellowish teardrop-shaped eyering extending... read more


    Song “ps-séét ptsick seet” or “tséé-wee pttuck tseep... read more


    Breeds in humid to semi-arid pine-oak (Pinus-Quercus), coniferous and dense... read more

    Food and feeding

    Arthropods; occasionally fruit. Arthropods include hymenopterans, coleopterans (of family Coccinellidae), bugs (Hemiptera), flies (Diptera... read more


    Mid-Apr to Jul; double-brooded. Nest a slightly oval cup made of moss, lichens (Ramalina menziesii, Usnea, Hypogymnia... read more


    Medium-distance migrant, wintering in Mexico; breeding birds in S Baja California (race ... read more

    Status and conservation

    Not globally threatened. Common to fairly common; overall population estimated at 8,300,000 birds. Densities in California (Douglas fir and oak forest in Humboldt and Trinity... read more

    Recommended citation

    Farnsworth, A. & Lebbin, D. (2019). Pacific-slope Flycatcher (Empidonax difficilis). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from on 12 December 2019).