Common Tern

Sterna hirundo (Linnaeus, 1758)

Речная крачка | Өзен қарқылдақ
summer plumage
juvenile

Distribution

In Kazakhstan breeds and occurs on migration almost everywhere excepting the waterless deserts. Please see the detailed races distribution of in the section Subspecies.

Biology

Common breeding migrant. Inhabits rivers and lakes with sandy, pebbly or saline soil shores and scanty vegetation; and rarer the lakes with reed-beds. In spring arrives in mid-April – early May in small flocks of 5-8 up to two dozen birds. Breeds both in small groups and in large colonies sometimes up to several thousand pairs, often together with Little Terns, waders and gulls; prefers the islands near the shore. Nest is located on the ground in shallow hole without lining or is lined with a few dry blades of grass; but in case of location nest in reed-beds the nest is built from the dry reed leaves and other plants on the heaps of old reed stems. Clutch of 2-3, rare 1 or 4-9 eggs (in last case several females lay eggs in one nest) is produced in the end of May to July. Both parents incubate clutch and care for chicks. Flying juveniles recorded from the end of June. Repeated nesting after loss of first clutches occurs often. Autumn migration begins is early, probably from the end of July. Common Terns leave the most breeding areas until the end of August – mid-September, some birds linger into the first decade of October.

Subspecies

Sterna hirundo hirundo (Linnaeus, 1758)

Description. The lightest subspecies, without the brownish tinge in color of plumage. The bill is red black-tipped, legs are red. Male wing length 247-285 (268), male bill length 43.0-49.0 (45.3) mm.
Distribution. Breeds almost in all plains of Kazakhstan. On seasonal migration occurs everywhere.

Sterna hirundo minussensis (Sushkin, 1925)

Description. Darker above and below than hirundo. Black on bill more extended. Legs colour varies from red to brownish-red. Male wing length 261-282 (273), male bill length 40.0-48.0 (43.0) mm.
Distribution. Probably breeds on Altai, in particular on Bukhtarma river and on Markakol lake, where in previous times was common on breeding, but since 1966 recorded only in summer and on migration. On migration possibly occurs in eastern and southern areas of Kazakhstan.

References

Gavrilov E. I., Gavrilov A. E. "The Birds of Kazakhstan". Almaty, 2005. Э.И.Гаврилов. "Фауна и распространение птиц Казахстана". Алматы, 1999. В.К.Рябицев. "Птицы Урала, Приуралья и Западной Сибири". Екатеринбург. Изд-во Уральского университета, 2000.