Mr. Ridgway met with the Poor-will from the eastern slope of the Sierra Nevada to the Wahsatch and Uintah Mountains. He describes its notes as much like those of the eastern A. vociferus, except that the first syllable is left off, the call sounding like simply poor-will, the accent on the last syllable. It frequents chiefly the dry mesa and foot-hills of the mountains, and lives almost entirely on the ground, where its two white unspotted eggs are deposited beneath some small scraggy sage-bush, without any sign of a nest whatever. Both sexes incubate.
Sternum of Chordeiles virginianus.
Sternum of Nyctibius jamaicensis.
Sternum of Caprimulgus stictomus.
Family CYPSELIDÆ.—The Swifts.
Char. Bill very small, without notch, triangular, much broader than high; the culmen not one sixth the gape. Anterior toes cleft to the base, each with three joints, (in the typical species,) and covered with skin or feathers; the middle claw without any serrations; the lateral toes nearly equal to the middle. Bill without bristles, but with minute feathers extending along the under margin of the nostrils. Tail-feathers ten. Nostrils elongated, superior, and very close together. Plumage compact. Primaries ten, elongated, falcate.