48 BRITAIN^S BIRDS AND THEIR NESTS. 



long plunge, the bird often striking the water with 

 sufficient force to submerge it completely and send up a 

 column of spray. Even on the shore in late September 

 the catch is shared with the young birds, showing perhaps 

 that skill in this sort of fishing is not easily acquired. 



THE ARCTIC TERN 



(Sterna macrura). 

 Plate 16. 



Very like the Common Tern is the Arctic Tern. So 

 great indeed is the similarity that our account of the 

 latter must be chiefly a record of slight differences. 



To begin with the bird itself. The Arctic Tern is 

 slightly smaller in build, but its actual length is greater, 

 owing to the longer outer tail-feathers. The bill is of a 

 brighter red and without a dull tip. The under-parts are 

 of a darker, grayer colour, but are entirely without that 

 faint suggestion of pink found in the Common species. 



Altogether, the adult birds in summer are distinguish- 

 able at a glance at close quarters, but only by a practised 

 eye under the usual conditions of observation. When 

 the birds are in the nestling, the immature, or even the 

 adult winter plumage, the difference is even less. A 

 curious point about the Arctic Tern in winter is that the 

 red legs become nearly black ! 



As regards the distribution of the two Terns, it may 

 be said that the gi-eater part of the British Isles lies 

 within the breeding range of both. Taking the coasts 

 separately, we find that the whole south coast of England 

 and the east coast up to the Fame Islands are the 

 exclusive territory of the Common Tern. From the 



