Ключевые слова: animal, animalia, ardea, ardea cinerea, ardeidae, aves, avian, beak, bill, bird, birdwatching, branches, chordata, chordate, cinerea, color, danube, eye, fauna, feathers, great, grey, grey heron, heron, herons bitterns, large, legs, long, natural, nature, neck, one, ornithology, outdoor, pelecaniformes, single, standing, tree, vienna, watchful, water, waterbird, white, wild, wild life, wilderness, wildlife, wings,