109. Empidonax flaviventris difficilis Baird. Western Yellow-bellied Flycatcher.
Both of the following specimens are more decidedly ochraceous than are my California examples, the latter, like many Pacific Coast birds, showing a closer approach to the eastern form. Difficilis, however, seems to be a pretty strongly characterized race, if not, as Mr. Ridgway has lately ranked it, a distinct species.
484, ♂ ad., Camp Lowell, June 3. Length, 5.50; extent, 8.10; wing, 2.60; tail, 2.46.
517, ♀ ad., Tucson, June 10. Length, 5.50; extent, 8.10; wing, 2.46; tail, 2.52.
110. Empidonax pusillus (Swains.) Baird. Little Flycatcher.—A common bird about Tucson, where it inhabited willow thickets near water. Numerous nests were taken: the one sent me is a loosely woven structure composed chiefly of dry grasses, with a neat lining of horse-hair. It agrees closely with northern New England nests of E. trailli, and like them differs widely from the compact, Yellow-Warbler-like nests which trailli builds in the region about Columbus, Ohio, and at St. Louis, Missouri.[[97]]
The series of skins is a full one, and the specimens uniformly sustain the characters ascribed to pusillus, a race which seems to me quite as constant as many which have been regarded with less suspicion and disfavor.
111. Empidonax hammondi (Xantus) Baird. Hammond’s Flycatcher.
172, ♀ ad., near Tombstone, April 12. Length, 5.40; extent, 8.90.
237, ♂ ad., Tucson, April 19. Length, 5.40; extent, 8.70.
363, ♀ ad., Santa Rita Mountains, May 12. Length. 5.30; extent, 8.30.