244 THE BIRDS OF THE BRITISH ISLES. 



have the back and wings mottled and barred with brown, the 

 cap is brownish, and the white on the forehead wide ; on the 

 carpal joint is a dark patch, which persists until the second 

 year. The bill is yellowish brown, the legs much duller yellow 

 than in the mature bird ; the irides in young and old are dark 

 brown. The white frontal patch of adult birds is broader in 

 winter than in summer. The outer primaries are black on 

 either side of the dusky shaft in mature birds, the inner web 

 having a pale margin, but in the young they are light slate. 

 Length, lo ins. Wing, 675 ins. Tarsus, o*6 in. 



Caspian Tern. Sterna caspia Pallas. 



Rather more than twenty examples of the Caspian Tern have 

 been recorded from the east and south coasts of England ; the 

 largest number from Norfolk. As it nests in Sweden and 

 Finland, as well as Spain and other parts of Europe, it is 

 surprising that it has not more frequently wandered on migra- 

 tion. It has a wide, almost cosmopolitan distribution, and does 

 not appear to vary greatly in different parts of its range. 



It is a large, rather heavily built tern with powerful flight, 

 easily distinguished by size alone. Its tail is short, its bill, strong 

 and slightly angled like thit of a gull, is vermilion, dark at the 

 tip, and its legs are black. The cap, which extends to below 

 the eye, is greenish black, and the dark grey primaries have a 

 frosted appearance ; the irides are almost black. Hume states 

 that its Indian name is " Keykra,* which as pronounced by 

 the natives approximates to its call. In autumn the black cap 

 is replaced by black streaks, as it is in the young, which have 

 the bill yellowish brown and the legs brown. Length, 20 ins. 

 Wing, i6*5 ins. Tarsus, i"6 ins. 



Gull-billed Tern. Skma anglica Montagu. 



The Gull-billed Tern (Plate 107) breeds on the western shores 

 of Europe from Denmark to Spain ; it also nests inland. It has 



