Dominant color of male Smew in breeding plumage is white. From bill-base to eye the broad greenish-tinged black strip passes; same color strip cross passes the nape, behind the extended feathers formed crest. Two narrow black strips are on each breast-flank. Back, outer shoulders, greater wing coverts anf flight feathers are black. Uppertail is dark-grey with pale tips of feathers. Flanks of body are with narrow grey wave strips. Tail is grey. Female has rusty-brown crown and rear-neck, white throat and fore-neck, almost black lores. There is small crest on nape. All upperparts are grey, darker on mantle, shoulders are browner. Craw, flanks and belly are white with not clear grey-brownish mottles; undertail is clear white. Wings as on male. Juveniles are similar on female, but all color are dim and underparts are almost dark-grey. Male in summer is undifferent from female. Bill is leaden, legs are grayish with darker web. Eyes are bluish-white in male and brownish in female and juvenile. Sizes: wing 175-205 mm, tail 67-80 mm, tarsus 28-34 mm, bill 25-30 mm. Weight: 450 - 750 gr.
Breeding of Smew recorded in Chernyy Irtysh river valley, on middle and lower parts of Ural river south to Mergenevo village. Generally widespread migrant, including through Altai (Irtysh river, Markakol lake). Rarely winters on open waters of Sorbulak lake, in valley of Chu river, middle part of Syrdarya river and on Caspian Sea. One recorded 15 Febuary 1964 near Kulsary village.
Smew is rare breeding migrant, but during spring and autumn its numbers are quite high. Inhabits forested rivers and lakes. Appears on small patches of open water in mid February - April, in pairs or small flocks, and migration ends mid - end May. Breeds in separate pairs. Nest is built in tree holes (Poplar, Willow, Elm), lined with plenty of down, not far above ground. Clutches of 8-11 eggs, probably in June as small chicks observed in early July. Autumn migration from September to November when lakes freeze - most numerous movements of 50 - 100 birds in October.
"Птицы Казахстана" том 1. АН КазССР. Алма-Ата, 1960. Gavrilov E. I., Gavrilov A. E. "The Birds of Kazakhstan". Almaty, 2005. Э.И.Гаврилов. "Фауна и распространение птиц Казахстана". Алматы, 1999.
