SANDWICH TERN. 247 



Other terns or Black-headed Gulls, consist of half a dozen to 

 fifty nests, usually close together. At Ravenglass most of these 

 groups of nests are on the slopes of the dunes amongst sparse 

 marram grass. As incubation proceeds the nests (Plate no) 

 become more and more evident, owing to the insanitary habits 

 of the sitting bird, and often they are surrounded by scattered 

 feathers. 



The eggs (Plate 94) are light in ground — creamy white to 

 rich buff — and are beautifully speckled, streaked, or blotched 

 with black, brown, and grey ; two is the usual number, but 

 single eggs are common. The light ground shows up the 

 markings, and they are much sought for on account of their 

 beauty by collectors, and for other reasons by Black-headed 

 Gulls. The parent birds are said to be less demonstrative in 

 defence of eggs and young than other species, but they certainly 

 stoop at the head of visitors to the colony with considerable 

 show of ferocity. The nestling in down is better protected by 

 its colour than the eggs, and though there are light and dark 

 phases, are on the whole lighter than other juvenile terns ; 

 light and dark young may be found in the same nest. The 

 paler birds are creamy white with a few black specks and dashes, 

 darker ones are rich buff, but in both forms the quantity and 

 depth of the markings varies. The bill is blackish, yellow, 

 yellow tipped with black, or even dull red ; the legs may be 

 greenish, purple, or plumbeous. When only a few days old the 

 young leave the nest and ramble, and, as Mr. C. Oldham 

 pointed out, conceal themselves by partially burying themselves 

 in self-made scrapes, exactly fitting their bodies, in the loose 

 sand. The habit is most marked with the older young, the 

 scoops being deeper ; Mr. Oldham found birds thus concealed 

 when partly feathered. In the first plumage the greyish-buft' 

 head is finely barred and speckled with black, and the mantle 

 broadly barred with black and buff. Their legs are lead- 

 coloured or purple, and bills yellowish horn or black with a 



