358 BIRDS OF TUNISIA 



as Japan, and southwards as far as Australia. In America it is found 

 in the Southern United States, and is generally distributed through- 

 out the West Indies, though rarer on the Pacific coasts of America. 



In its habits the Sooty Tern is eminently sociable and gregarious, 

 breeding in immense colonies, densely packed together, on small 

 rocky islands, and laying its single egg on the bare ground, or, as on 

 Ascension, on an arid cinder-bed. 



The species would seem to be far from shy or wary, though when 

 wounded and seized by the hand, capable of defending itself and of 

 inflicting a severe bite. Its usual note is loud and shrill, but at times, 

 and particularly when its breeding quarters are approached, the bird 

 utters a plaintive cry. It feeds principally on fish, but, like some 

 other sea-birds, will hover near vessels and pick up scraps of food or 

 any morsels that may be thrown overboard. 



The closely allied species, Sterna ancestheta of Scopoli, which 

 differs from S.fuliginosa in its smaller size, hghter colouring and less 

 fully webbed feet, is said to have occurred once in England, but the 

 evidence in support of this statement is not quite satisfactory. 



HYDROCHELIDON HYBRIDA (PaUas). 

 WHISKEKED TEEN. 



Sterna hybrida, Pallas, Zoogr. Bosso-As. ii, p. 338 (1811). 

 Hydrochelidon hybrida, Bonap. Cat. Ucc. Eur. p. 77 (1842) ; Locke, 



Expl. Sci. Alg. Ois. ii, p. 208 (1867) ; Koenig, J. f. 0. 1888, p. 288 ; id. 



J. f. 0. 1893, p. 99; Saunders, Cat. Birds Brit. Mus. xxv, p. 10; 



Whitaker, Ibis, 1895, p. 106. 

 Sterna leucopareia, Malk. Faune Orn. de I'Alg. p. 31 (1855). 



Description.— XAvAt male, spring, from Tunis, North Tunisia. 



Forehead, crown and nape jet-black ; remainder of upper plumage grey, 

 darkest on the mantle ; primaries with dark grey lines bordering the shafts ; 

 shoulders edged with white ; chin and cheeks white, rest of the under parts 

 grey, darkest on the abdomen ; under tail-coverts white ; under wing-coverts 

 white ; toes only slightly webbed. 



Iris dark brown ; bill and feet dark red. 



Total length 1025 inches, wing 9-50, culmen 1-35, tarsus -90. 



Adult female similar to the male. 



In winter the forehead is white and the crown and nape white marked 

 with black. 



