BLACK TERN 



165 



crustaceans and other swimminL^ invertebrates, while others, again, 

 prey chiefly upon insects. In the general colouring of their plumage 

 most terns are very similar to gulls ; many of them having black on 

 the head. The black area is, however, smaller, but in many cases 

 persists throughout the year, only becoming somewhat paler in winter. 

 In certain species the black extends over the greater part of the 

 plumage of the adult in summer. 



The black tern and its relatives, as the name implies, are 

 characterised by this general darkening of the breeding-plumage of 

 the adult ; but more especially by the relative shortness of the tail, 

 which is scarcely forked and much inferior in length to the wings, and 

 also by the deep notch- 

 ing of the webs con- 

 necting the front toes. 



The black tern, 

 which formerly nested 

 in the fen-districts of 

 England, ranges over 

 the greater part of 

 Europe to the south- 

 ward of latitude 30^, 

 extending as far east- 

 wards as Turkestan, 

 while in winter it 

 travels to Africa, where 

 it is found a long 

 distance down both 

 the west and the east coast. In the western hemisphere it is re- 

 placed by the American black tern {H. siirinaviensis), which is a 

 darker bird with black feet ; from the other two representatives of the 

 genus, of which, as noticed below, stragglers occasionally reach our 

 islands, it is readily distinguished by the grey colour of the under 

 wing-coverts of the adult in summer-plumage. In addition to this 

 special feature, the black tern in summer-dress may be recognised 

 at a glance by the dull lead-grey tone of the plumage, relieved only 

 by the white of the lower flank-feathers and under tail-coverts, and 

 the pale grey under wing-coverts ; the beak being black and the 

 legs purplish brown. In winter the forehead, face, neck, and under- 

 parts are white, as in the white-winged whiskered species at the same 

 season. In length the black tern does not exceed about 9^ inches. 

 Immature birds resemble the adults in winter, but have the feathers of 



) WARD STUDIOS 



BLACK TERX (SUMMER). 



