Ключевые слова: adult, america, animal, avian, barn, beautiful, biodiversity, biology, bird, blue, branch, calm, colorful, conservation, countryside, ecology, ecosystem, environment, environmental, fauna, feathers, forest, glossy, hirundinidae, hirundo, maryland, meadow, nature, north, ornithology, passeriformes, passerine, peaceful, perched, perching, plumage, rustica, serene, shade, shady, shiny, spring, summer, swallow, tree, twig, wild, wildlife, woodland, zoology,