252 THE BIRDS OF THE BRITISH ISLES. 



Black Tern, and the bill and legs are strikingly red. The 

 wings are greyish slate, almost pearl-grey on the secondaries, 

 and the primaries, though really blackish, are so frosted as to 

 appear pearl-grey ; thus the whole wing, apart from the white 

 patch, is considerably lighter than that of the Black Tern. 

 This difference is reversed in the under wing, for the under 

 wing-coverts and axillaries in this bird are black, and in the last 

 species suffused with grey ; the effect is that as the bird cants 

 in flight the upper surface shows lighter than the under in the 

 White- winged Tern, and vice-versa in the Black. Its habits, at 

 any rate when on migration, closely agree with those of its 

 congener ; it catches insects and small fish, stooping to the 

 water or taking the former in the air, and its flight is equally 

 slow and desultory. 



In winter the head, except for the blackish nape, the neck, 

 and under parts are white, but the tail is suffused with grey and 

 the under wing becomes paler, but not so pale as that of the 

 Black Tern at the same season. The young bird is at first 

 mottled with brown and buff on the head and upper parts, 

 but during its two years' progress to maturity it gradually 

 loses the brown feather edgings ; the back of the head and 

 neck become sooty, a greyish patch shows on the checks, 

 and the wings become a purer grey. The upper tail-coverts in 

 the second year are very nearly white, sufficiently so as to 

 contrast with the pale grey tail, whereas in the Black Tern 

 there is no appreciable difference. The bill and legs of young 

 birds are brownish, the irides at all ages brown. Length, 

 9'3 ins. Wing, 8'25 ins. Tarsus, 075 in. 



Whiskered Tern. Hydrochelidon kticopareia (Temm.). 



Southern Europe and north Africa, eastward to India, is the 

 summer range of the Whiskered Tern, and it winters further 

 south ; it is hardly surprising that it is a rare bird in Britain. 



