Ключевые слова: animal, avian, beak, bill, bird, birdsong, birdwatching, black, blue, blue sky, call, canary, chirp, cook county, cook county forest preserve, elm, fauna, forest, green, illinois, isolated, leaf, leafy, leaves, no people, one, ornithology, passerine, perch, perched, profile, sing, singing, single, sit, sky, skyline, solitary, songbird, spears woods, united states, warbler, woodland, yellow, yellow warbler,