Sandwich Tern

Sterna sandvicensis (Latham, 1787)

2011-06-22 Northern Caspian Sea	© Victoria Kovshar

Description

Adult Sandwich Terns in spring plumage have black upper-head to the line of eyes, the feathers of nape elongated and formed the crest. The mantle is pale-grey. Fly feathers are dark with white borders of inner webs. Head-flanks, all underparts and tail feathers are white sometimes with pink tinge on breast and belly. Bill is black yellow-tipped, legs are black with yellow soles. Eyes are dark-brownish. The distinction of winter plumage is in white fore-head and lores, with black streaks on crown. The feathers of nape are brownish-black, often with white edges. Juveniles have greyish-black “cap” with buffy edges of feathers and white mottles. Feathers of mantle are buffy-tinged with blackish streaks formed angles on feathers. Sizes: wing 290-325 mm, tarsus 25-30 mm, bill 50-58 mm. Weight: 200-275 gr.

Distribution

Sandwich Tern breeds on Caspian Sea in Mangyshlak area and near Atyrau on Peshnoy island. Vagrants recorded 14 May 1883 near Orenburg, 21 June 1914 at Aral Sea and 25 June 1930 close to Syrdarya delta.

Biology

Sandwich Tern is rare breeding migrant. It inhabits marine low cockle-shell or sandy islands without, or nearly so, vegetation. Arrives in April. Breeds in dense colonies, at 10-30 cm each pair of other, together with Common and Little Terns, Slender-billed Gull often. Nest is shallow hole without lining. Clutches of 1-2, very rare 3 eggs in end June – July. Both parents incubate for 22-23 days, juveniles fledge at 35 days old, up to mid-August. On Mangyshlak intense migration to north observed at end July 1951 and 1952, but this not explained. At autumn latest birds recorded in October.

References

"Птицы Казахстана" том 2. Алма-Ата, 1962. Э.И.Гаврилов. "Фауна и распространение птиц Казахстана". Алматы, 1999. Gavrilov E. I., Gavrilov A. E. "The Birds of Kazakhstan". Almaty, 2005.