VAUX SWIFT. Chaetura vauxi (Townsend)

Field characters.—Size about that of Violet-green Swallow; form and behavior like those of White-throated Swift. Plumage plain blackish brown, except for silvery suffusion on breast and throat. No white on flanks.

Occurrence.—Noted in Yosemite Valley in fall (Mailliard, 1918, pp. 16, 18). Not observed by us. Courses in open air, during day time.

The Vaux Swift may be known in flight from the more common and better known White-throated Swift by its smaller size, lesser degree of whiteness on the throat, and by the absence of white on its flanks. It is distinguished from the Northern Black Swift by its much smaller size and by the silvery appearance of its throat and breast.

This swift has been reported from Yosemite Valley by only one observer, Mr. Joseph Mailliard (as above), who found it present in some numbers in the early fall of 1917. "One or two often seen, and quite a flock at times"; this statement referring to occurrence on August 21 and for a few days subsequently (Mailliard, MS).

Mr. Donald D. McLean reports the Vaux Swift as having occasionally been seen by him in spring and summer at his home place 6 miles east of Coulterville.