White-Throated Swift
425. Aeronautes melanoleucus. 6½ inches.
A handsome bird, in fact, the most beautiful and graceful of this family. Its flight is very rapid, and they congregate in thousands about the tops of inaccessible cliffs, where in small burrows in the earth or under the sods, or in crevices they build their nests, which are generally made of roots and grasses and lined with feathers. Four or five dull white eggs are laid (.85 ×.50).
Range.—Western United States, mostly in the Rocky Mountains, and in California ranges north to Canada borders.