Adult Bewick's Swans are all white. Legs are black. Eyes are dark-brownish. Tip of bill is balck, base of bill is yellow; the yellow passes only to rear edge of nostril. Bewick's Swan is very similar to Whooper Sawn, but distinguished by lesser size and much black on bill. Juvenile Bewick's Swans are grey above; belly and undertail coverts are white. Base of bill are meat-red, legs are reddish-black. Sizes: wing 480-560, tail 140-175, плюсна 110-114, клюв 84-100 мм. Вес 4900-6200 гр.
"Птицы Казахстана" том 1. АН КазССР. Алма-Ата, 1960.
