Birds of Britain 

 THE ARCTIC TERN 



Sterna macrura, Naumann 



Except in a few minor points of plumage and in its dis- 

 tribution this species is the counterpart of the preceding 

 one. In England it is only met with on migration, though 

 a few pairs may nest in the north, but in Scotland it is the 

 commonest Tern, breeding in increasing numbers northwards. 

 In Ireland it breeds commonly, especially on the wind-swept 

 islets of the north and west. Elsewhere it breeds in cir- 

 cumpolar regions, and has been met with in winter in 

 Antarctic seas, so that it has a latitudinal range of from 

 82° K to 74° S., probably the largest range recorded for 

 any one species. 



Its nesting habits are similar to those of the Common 

 Tern, and as a rule it collects absolutely no materials for a 

 lining, but lays its eggs in a shallow " scrape " or even on 

 the bare rock. The eggs are indistinguishable in colour 

 from those of the Common Tern, but are on the average 

 slightly smaller. To the experienced ear the note is also 

 rather different, but that difference is too shght to be 

 expressed on paper. 



This species may be distinguished from the preceding 

 species by its blood-red bill, which is not darker at the tip, 

 and the shorter tarsi. The under parts, especially in summer, 

 are much darker, and the stripe on the inner web of the 

 flight feathers is narrower and darker than in S. fluviatilis. 

 In other respects these species are almost indistinguishable. 

 Length 14 -5 in. ; bill 1'6 in. ; tail 7*5 in. ; wing 10 in. 



