Ключевые слова: avian, aviary, back, beak, belly, bill, bird, birds, birdwatching, breast, claw, cold, courtship, crane, dance, eye, eyes, face, feather, feathers, freeze, frost, grus japonensis, head, hoarfrost, hokkaido, icing, japan, mate, mating, mating call, mating season, ornithology, plumage, plume, redcrowned crane, snow, snowflakes, tail, talon, wing, wings, winter,