Ключевые слова: animal, avian, beak, bird, bird watching, blue, conservation, eco, ecology, environment, feather, feathers, iridescent, migration, migratory, nature, north america, ornithology, passerine, perch, perched, plumage, songbird, species, swallow, tachycineta, tachycineta bicolor, tree, tree swallow, vertebrate, white, wildlife, wing, wings, zoology,