Black Tern

Chlidonias niger (Linnaeus, 1758)

		adult summer -> winter
2015-06-27 Bakchar. Tomskaya oblast. 2012-07-14 Malkovo, Kupinskiy Raion, Novosibirskaya Oblast.	© Mishail Belousow © Sergey Pisarevskiy

Biology

Common breeding migrant. Inhabits the fresh lakes, ponds and slow-current rivers covered by surface vegetation; and sometimes the sedge marshes. In spring appears in mid-April to May; arrives in small flocks of 8-20 very rare up to 70-100 birds. Breeds mostly in colonies of 10-100 pairs, and very rare by separate pairs. Nest is located on the small heaps of the dry reed stems or on the leaves of the water vegetation (waterlily for example); nest is built from the dry pieces of the reed stems and reed-mace, on the distance 0.5-2.5 m one from another. The main part of the nest is set under water. Clutch of 1-4 (usually 3) eggs produced from the mid-May until the early July. So long breeding period explained by the repeated breeding after the loss of first clutch (mostly because of Marsh Harrier hunting). Both parents incubate for 14-17 days and care for juveniles, which hatch in mid-June – early July and begin to fly at age 20-25 days old. The flying juveniles recorded very rare in the end of June, mostly in July – early August. The autumn migration is early, most of birds departed the breeding areas until the end of August.

References

В.К.Рябицев. "Птицы Сибири". Москва-Екатеринбург, Изд-во "Кабинетный ученый", 2014.