Barn and Cliff Swallows were swarming on the beach at lake Temescal in Oakland, CA today. Apparently there was a particularly good site on the beach for collecting the type of mud used for nest construction.
Cliff Swallows once nested on the steep cliff faces of rocky canyons and river valleys, but more recently have taken up residence on the walls of buildings where a colony may construct a huge dormitory of adjoining mud nests. These are the famous “swallows of Capistrano” that fly 6000 miles north each year from Argentina to the mission at San Juan Capistrano about the third week of March (usually on St. Joseph’s day, March 19) and leave again to fly south for the winter on roughly the same date in October.
Barn Swallows once nested in caves (or in barns), but now build their mud nests on a variety of human structures, like the housings for lights in a tunnel underpass. This species is one of the most widely distributed in the world, migrating from the southern hemisphere where is overwinters to breed in the northern hemisphere each year.
Violet-green Swallows are a western species, and closely related to Tree Swallows which they resemble in body form and habits. Like Tree Swallows they utilize nest holes in trees, which they line with grass and feathers and prefer more open areas near woods for foraging.