124 THE BRITISH NATURE BOOK 



silent bird, but on the wing emits a low double whistle. Both sexes " quack," 

 but in a lower key than other " ducks." 



Tern, Arctic. Does not breed on our southern shores, and generally is 

 a more northerly summer visitor ; it is also less of a fresh-water-haunting 

 species. It is distinguished from the Common Tern by its uniform blood-red 

 beak, its dark grey under colouring, and the narrower band of grey on the 

 outer primaries (see COMMON TERN). The nest is the same ; but there are more 

 often two than three eggs, and they are usually deeper in ground colour and 

 bolder in markings, slightly smaller in size. 



The note is " Kerr," occasionally " Kerr-err." 



Tern, Common. This species is widely distributed in the British Isles 

 wherever the coast makes a suitable breeding ground, which may be bare, 

 water-worn rock, shingle beds, sandy flats with or without vegetation. The 

 nest is a scrape, with or without a scanty lining of bents or other material. 

 The eggs, generally three, vary in ground colour, dull grey to brown, boldly 

 blotched and spotted. I have found them of a beautiful sea-blue on a famous 

 shingle beach in Dorset. In any case, they are so like the ground upon which 

 they are laid that they are difficult to see. I have taken a friend amongst the 

 colony, and had to check him again and again to prevent his treading on nests 

 which he did not see. The bird is so like the Arctic Tern that the two species 

 are often confused. Both possess the beautiful coloration of black, grey, and 

 white. The Common Tern has, however, an orange-red beak for two-thirds of 

 its length ; the remaining third is black ; and the band of dark grey on the inner 

 side of the white shaft of the outer primaries is much broader than that of the 

 Arctic Tern. In addition, the under parts are a pale vinaceous grey, the 

 Arctic Tern's being darker. It is also distinguished by its cry, a long-drawn 

 and plainly two-syllabled " Keee-yerrr." 



Tern, Sandwich (see notes on LITTLE TERN in preceding group). This 

 bird (i6| inches) is the largest of the British terns, and may be identified 

 by its stouter build, its black beak (with yellow tip) and legs, and the long, 

 pointed feathers on the nape a sort of black mane. When flying, note its 

 shorter tail, and longer beak, and also its distinctive cry " Kirr-whit." There 

 is also an alarm note, something like " Quk " or " Keek." 



In the British Isles the colonies of this species are not numerous, but 

 it has bred in Kent and Norfolk. There are large colonies in Cumberland, 

 and in certain parts of Ireland and Scotland. It is a summer visitor, arriving 

 first towards the end of March. It breeds in close colonies on sandy flats, 

 often with a scanty growth of plants, such as marram grass. The nest is gen- 

 erally a slight hollow, sometimes lined with scanty dried grass, etc. The eggs 

 (two, rarely three) are grey or brown stone-colour, with blotches and spots of 

 deeper brown. Note their size : 2 x i| inches. 



These birds feed on small fish, aquatic insects, and small crustaceans. 



Waterhen (commonly MOORHEN). A bird to be found on almost every 

 pond and river, recognized by the white markings on the under tail which it 



