616. Riparia riparia. 5½ inches.
The whole of North America north to the limit of trees, and south to the Gulf of Mexico, breeding from the middle portion of the United States northward. These birds build their nests in sand banks in almost all sections of the country, digging a small tunnel from one to three feet in length, enlarged and lined with grass at the end. They lay from four to six pure white eggs (.70 × .50).
ROUGH-WINGED SPARROW.
617. Stelgidopteryx serripennis. 5½ inches.
This species is about the same size as the last, and similar, but with the throat and breast grayish in place of the white. The outer webs of the outer primaries are recurved, forming a series of hooks. It nests in holes of embankments or in the crevices of cliffs, or among the stones of bridges and buildings. Their eggs are four in number and are pure white (.75 × .52). The range of these birds covers the whole of the United States, breeding from Mexico to British Columbia.
BOHEMIAN WAXWING.
618. Bombycilla garrula. 8½ inches.
A northern variety, breeding in Alaska and northward, winters to California and the northern states of the United States. It may be identified from the following by the markings on the wings of white and yellow, and the larger band of yellow at the end of the tail. The wax-like appendages on the wings and tail may be found on both species.
Their nests are made of rootlets, grass and moss, and placed in bushes or trees at a few feet from the ground. Usually four eggs are laid, of a grayish color, sharply spotted with brown (.95 × .70).