Breeding biology and behavior of Hammond's and western flycatchers in northwestern California

Abstract

The Hammond's (Empidonax hammondii) and Western (E. difficilis) flycatchers are sympatric within portions of their breeding ranges in north- western California. Westerns are common in a variety of habitats (Bent 1942:247, Johnson 1980:11-23); Hammond's are more abundant at higher elevations (Bent 1942:226, Johnson 1963:140-143). Only one ma- jor study of each species' breeding biology has been reported; both looked at the species in places where they do not occur together. Davis et al. (1963) studied the breeding biology of Westerns in a hardwood-dominated forest in northern Monterey County, California. Davis (1954) studied the breeding biology of Hammond's in mixed coniferous and deciduous forests at Flathead Lake, Montana. More knowledge is needed of both species' breeding ecology and behavior where they are sympatric on their nesting grounds. I report here on a comparative study of the breeding behavior and biology of color-marked birds.

Citation

Sakai, H.F. 1988. Breeding biology and behavior of Hammond''s and western flycatchers in northwestern California. Western Birds. 19(2): 49-60.