Ключевые слова: animal, animals, avian, bicolor, bird, birdhouse, blue, building, conservation, couple, eco, ecology, environment, family, feather, feathers, home, house, iridescent, male, mating, migratory, natural, nature, nest, nesting, nobody, north america, one animal, ornithology, pair, park, passerine, songbird, species, swallow, tachycineta, tachycineta bicolor, tree swallow, usa, vertebrate, wild, wildlife, wing, zoology,