632 COMMON TERN. 



Tern on the Fames, where large colonies undoubtedly breed in some 

 seasons. In Ireland it is the more plentiful bird in the south, while 

 it appears to rival the Arctic Tern in the north, and there also it 

 frequently nests by the margin of fresh water. It usually comes to 

 us at some time in May, the autumnal migration lasting from August 

 to October, and on passage it may often be observed on rivers and 

 inland waters, even on the Serpentine &c. in London. 



During the warmer months this species is widely distributed on 

 the coasts, rivers and lakes of Europe, from Norway to the Medi- 

 terranean, Black and Caspian Seas, and thence westward to the 

 islands of the Atlantic. Across that ocean we find it abundant in 

 North America, from Labrador to Texas, but it has not yet been 

 recorded froni the Pacific. Returning to the eastern hemisphere, we 

 trace it down the west side of Africa to Accra in winter ; and in 

 Asia it is found in summer on the low land from the Caspian to 

 Merv, but on the elevated lakes of Cashmere, Tibet and Southern 

 Siberia it is represented by S. tihetajia, which has a darker general 

 hue, a more vinous tint on the under parts, and smaller bill and feet; 

 this form visits Ceylon and South Africa in winter. 



The eggs, usually 3 in number, are laid on sand, shingle, dry 

 wrack or even short herbage near water, a few crossed bents 

 being occasionally added ; they vary in colour from dull grey to 

 stone-buff, blotched with bluish-ash . and dark brown : average 

 measurements 17 by I'l in. In cold seasons {q'n birds have begun 

 laying by the last days of May, and incubation does not become 

 general until June. On the approach of an intruder the parents 

 utter a sharp //>/-^, and when their young are hatched they will often 

 skim over the spot and drop small fish close to the nestlings, whose 

 mottled colour renders them almost indistinguishable from the 

 surrounding shingle. The food consists chiefly of young coal-fish 

 and sand-eels, with shrimps and other crustaceans. 



The adult in summer has the bill orange-red, horn-colour at the 

 tip ; head and nape black ; mantle pearl -grey ; rump and tail white, 

 except the two lateral pairs of streamers which are grey on the outer 

 webs ; under parts nearly white, with a vinaceous-grey tinge on the 

 breast and abdomen ; legs and feet orange-red. In winter the fore- 

 head is sprinkled with white. Length i4'25 in., wing io"75 in. The 

 young bird has the crown and nape streaked with blackish-brown ; 

 mantle barred with ash-brown, which gradually disappears till only a 

 dark band along the carpal joint remains ; tail-feathers grey on their 

 outer webs ; under surface white ; bill, legs and feet reddish-yellow, 

 turning nearly black in winter. 



