GRAY FLYCATCHER. Empidonax griseus Brewster

Field characters.—As for Wright Flycatcher (which see). Judging from specimens in hand the following features might prove usable in life if the bird be seen at close range and he in fresh, unworn plumage: Coloration as in Wright Flycatcher but paler, more ashy gray; general size slightly greater; bill longer and proportionately narrower, with base of lower mandible pale-colored, rather than dark throughout. Voice: As far as learned, like that of Wright Flycatcher.

Occurrence.—Summer visitant to lower levels east of the Sierras. Specimens taken in 1916 in Mono Lake district as follows: near Williams Butte, May 6; at Mono Mills, June 8; and on Dry Creek (at 6600 feet altitude) north of Mono Mills, June 11. Also rare transient on west slope of Sierras, at Dudley, 6 miles east of Coulterville (specimen in D. D. McLean collection taken May 20, 1916). Inhabits tracts of large-sized sage and Kunzia bushes.

When a group of birds is so difficult of field identification as are the small flycatchers, only through long-continued practice can one expect satisfactorily to approach facility in recognizing the species. The Gray Flycatcher is sharply set off from both the Traill and the Western on the ground of voice; but this test fails absolutely in differentiating the Wright; and, in our experience, the Hammond has not sufficient individuality always to be identified with certainty. Behavior seems to be identical in the Gray, the Wright, and the Hammond, so that there remain as means of identifying the Gray, only the few structural features indicated above; and these are so small that, even with series of specimens, doubtless as a result of individual variation, uncertainty as to the exact allocation of some particular specimen now and then confronts us.

Of all the Empidonaces, the Gray Flycatcher is largest and grayest; the contrast, when specimens are compared, between the Gray and, say, the Hammond, is quite apparent. But it must still be urged that such differences are not great enough to serve in identification at a distance, with the birds flitting about elusively amid surroundings of varied light and shade.

The Gray Flycatcher, when settled for the summer, is a bird of the arid Great Basin fauna. It enters the Yosemite region in the environs of Mono Lake, where our limited information suggests its restriction to the tracts of sagebrush and Knuzia where these bushes reach largest size. In this sort of 'chaparral,' the Gray Flycatcher doubtless nests, as does its near relative, the Wright, in the darker-hued, more typical chaparral of the Sierras. It is interesting to note that the Wright Flycatcher, as a breeding bird, was found to extend eastward down the slopes of Leevining Peak nearly or quite to the edge of Mono Lake; it there becomes a close neighbor of its very near relative, the Gray Flycatcher.