Cliff Swallow (Petrochelidon pyrrhonota) clinging to stucco wall prior to constructing nest.

anisodactylous, asynchronous, avian, beak, bill, bird, bridges, cave swallow, chatter, cliff swallow, clinging, cloaca, colonial, construction, flock, flocks, foraging, gape, gragarious, grasp, grip, hirundinidae, incubation, insectivores, insectivorous, insects, iridescent, migration, moult, mud, nest, nesting colony, ornithology, oscines, palpation, passeriformes, pelagic, perching, petrochelidon, pyrrhonota, remiges, retrices, social, song bird, swallows, swollen seminal vesicles, synchronous, ubiquitous, white forehead, wings,