248. Sterna fluviatilis.
THE COMMON RIVER-TERN.
Male 12 1/2" to 14 1/4". Legs red. Bill deep red. Black markings on bill near tip. Wings reaching beyond tail. Remiges twenty-nine. Tail-feathers grey, with white on inner webs. Abdomen greyish. First primary, outer web black, and a broad streak of dark grey next the white shaft on inner web. Rest of inner web white, and tip ash-grey.— In winter: Crown streaked and mottled with white. Temperate regions of Asia, Europe, and N. America, ranging into Ladak and higher Himalayan valleys. In winter visiting India and Ceylon. Eggs (1.75 x 1.2) olive, blotched brown and grey. (J. 986. B. 1506.)
Also S. macrura. 14" to 15". The Arctic Tern. Legs red. Bill red. White streak from base of bill to side of neck. Mantle pearl-grey. Outer web of first primary blackish. Shaft white, and narrow line of grey on inner web, which is white, with ashy tip. Tail-coverts white. Abdomen French grey.— In winter: Forehead and crown mottled white, Circumpolar and in winter southwards to coasts of America and Africa and to 66° S, lat, in Southern Ocean.
S. hirundinacea. 16 1/2". Bill and legs red. Rump and tail white. Below nearly white, S. America.
S. vittata. 16". Bill and feet cherry-red. White moustachial streak prolonged to the nape. Below grey. S. Atlantic.
S. virgata. 13". Bill and feet red. Mantle and under parts dark smoky grey. Kerguelen Island and the Crozettes.
S. albistriata. 12". Legs and hill yellow. Broad streak of white passes under the eye to the nape. Mantle dark grey. Breast and abdomen pale grey.— In winter: Head grey. New Zealand.
S. fosteri. 14" to 15". Legs and bill orange. Forehead, crown, and nape sooty black. Abdomen white. Outer web of long tail-feathers white. Inner web dark grey. N. America.
Wing 6 1/2" to 7 1/2".