CLIFF SWALLOW
612. Petrochelidon lunifrons. 5½ inches
Adults similar in plumage but the female slightly paler. Easily distinguished from the [Barn Swallow] by the square tail and light buffy forehead and rump.
This is what is commonly called the Eave Swallow in the East, because of its habit of plastering its nests on the outside of barns or other buildings, up under the eaves. In the West they usually resort to cliffs where, sometimes, large sections of the face will be completely covered with the little mud flasks; often colonies of several thousand will build their nests together.
Song.—A continuous twitter, uttered while on the wing or at rest.
Nest.—A flask or gourd-shaped structure of mud, lined with straw and feathers, attached under the eaves to the outside of buildings or on the faces of cliffs; five to seven eggs are laid; white dotted and spotted with reddish brown (.80 × .55).
Range.—N. A., breeding from the Gulf to Greenland and Alaska; winters in the Tropics.
