SWIFTS 
229 
wing. Their voice also marks them. They do not boom or give 
the quank characteristic of other members of the family. Mr. Bai¬ 
ley describes their notes as a low rapid chuck, chuck, chuck, followed 
by a soft purYr’r’r’rY, which, when several birds are about, be¬ 
comes almost incessant. 
In parts of southwestern Texas during the breeding season the 
Texan is the only nighthawk, and Dr. Mearns states that he has 
never known henryi to infringe on the territory of texensis in the 
breeding season, henryi nesting in the pines and spruces of Transi¬ 
tion and Boreal zones; texensis below the pines in Lower Sonoran 
zone. In California, Mr. Grinnell says, texensis nests in dry parts 
of river-beds and sandy places among sagebrush. 
FAMILY MICROFODIDiE : SWIFTS. 
KEY TO GENERA.. 
1, Tarsus and part of toes feathered. Aeronautes, p. 232. 
1. Tarsus and toes naked. 
2. Tail feathers tipped with spines . . Chaetura, p. 230. 
2'. Tail feathers not tipped with spines . Cypseloides, p. 229. 
Fig. 294. 
GENUS CYPSELOIDES. 
422. Cypseloides niger borealis ( Kenn .). Black Swift. 
Tail slightly forked ; tarsus and toes naked, the hind toe pointing back¬ 
ward. Adults: dusky or blackish, 
lighter on head and neck, the forehead 
hoary, a velvety black area in front of 
eye. Young: similar, but feathers 
tipped with whitish. Length: 7.00- Fig. 295. 
7.50, wing 6.50-7.50, tail 2.30-3.00. 
Distribution. — From the Rocky Mountain region west to the Pacific, 
and from British Columbia south to Lower California and Costa Rica. 
Nest. — On cliffs or about buildings. One described by M. H. Gorm- 
ley, on the cornice of a building, made of straws, chips, and horsehair, 
lined with green leaves and paper. Eggs : 5, white. 
Food. — Insects. 
The black swift has been found breeding on inaccessible cliffs in 
various parts of the west, but little that is peculiar has been discov¬ 
ered about its habits except that it is less noisy than most of the 
swifts. A nest was accidentally discovered by Mr. Vrooman at 
Santa Cruz when collecting cormorants’ eggs on the cliffs. 
Mr. Rathbun says the swifts may be seen circling about above the 
city of Seattle, rarely being seen, except when rain threatens, lower 
than from 300 to 500 feet. 
