SWIFTS: NORTHERN BLACK SWIFT 
349 
rump and upper tail coverts; crissum almost pure white. Four years are supposed 
to be required to complete the adult plumage. 
Comparisons. —Of the three swifts that have been found in New Mexico only 
the Chimney Swift has the spine-tipped tail. The White-throated, while having 
the same tail form as the Black, may be distinguished at a glance by the long white 
wedge of the throat and underparts and the white flank patches. (See pp. 351.) 
Range. —Western North America and southward to southern Mexico. Breeds 
from southeastern Alaska and southern Colorado south to Mexico; winters in 
southern Mexico. 
State Records. —Since the Black Swift breeds in central Mexico and north to 
southern Colorado, it ought to nest in New Mexico, but as yet there is no record of 
the presence of the bird in the State during the summer. It has been noted twice in 
fall migration, once at Willis in September, 1S83 (Henshaw), and once at Lake Bur- 
ford September 28, 1904 (Gaut).—W. W. Cooke. 
Nest. —Commonly in crevices of inaccessible mountain cliffs. Some in the ^ osem- 
ite, found by Mr. and Mrs. C. W. Michael on canyon walls and behind or near a 
waterfall, thick or shallow round nests made of moss or pinnae of five-fingered fern; 
also a few found by Mr. A. G. Vrooman on sea-cliffs, on a shelf or bracket, a slight 
unlined depression in moist sod. Egg: 1 white, large. 
Food. —Winged ants, in some cases 99 per cent; also alkali flies, etc. 
General Habits. —The Black Swifts, Major Bendire found to be 
“extremely social birds, rarely seen singly even during the breeding 
season.” In southwestern Colorado, he says, in 1883 Mr. Anthony 
found them very abundant, “nesting in all of the highest crags, but 
never in places accessible to anything not provided with wings.” On 
the upper Columbia, near Lake Chelan in July, 1879, the Major found 
quite a colony nesting in an almost perpendicular cliff, fully three 
hundred feet high. As he says, “they evidently had young, and the 
twitterings . . . could readily be heard as soon as a bird entered 
one of the numerous crevices in the cliff above.” The nests must 
have been “placed well back in the fissures, as nothing bearing a 
resemblance to one was visible from either above or below” (1895, 
pp. 175-176). While the Swifts breed ordinarily in such localities, no 
actual nests had been discovered until, in the sea-cliffs of Santa Cruz, 
Mr. A. G. Vrooman found a small colony, and during a period of years, 
by examining the face of the cliff from a rope ladder, found the nests, 
the extraordinarily large, single eggs, and also the nestlings (1901, 
p. 395). 
The Black Swifts evidently nest far within the Cascade Mountains 
in the region of Seattle, where their general habits and their daily 
flights to their feeding grounds in the valley below were carefully 
watched by Mr. Samuel Rathbun for a term of 3 r ears. “On fair days,” 
he says, the Swifts flew high—often to the limit of sight, and when it 
rained they would descend to a height of from two hundred to five 
hundred feet (1925, p. 501). In the Yosemite, Mrs. Enid Michael 
found them coursing back and forth through the mist of Vernal ball, 
