54 



BRITISH BIRDS 



Fig. 65. Arctic-tern's primary. 



Eggs. Usually 2. Greyish to deep buff, spotted and blotched 

 with shades of brown and underlying ash or brown. Av. size, 

 2 '03 x 1*42 in. Laying begins in the first half of May. One 

 brood. 



106. Common-tern [Sterna hirundo Linnaeus; Sterna 

 fluviatilis Naumann]. Summer visitor, and found breeding 

 usually on the sea-coast in the British Isles. 



Bird. Length 14J in. See Sandwich-tern. Easily confused 



with the Arctic-tern, which 

 it closely resembles. Both 

 have the upper-part of the 

 head and nape black, the 

 rest of the plumage mostly 

 a silvery-grey, the white 

 rump, throat, and upper 

 and under-tail coverts ex- 

 cepted ; legs red. They 

 may be distinguished most 

 surely by the relative 

 breadth of the dark inner 

 band on the outer primaries 

 and the coloration of the 

 bill, which is blood-red to 

 the tip in the Arctic and 

 in the common-tern, coral 

 red on the basal two-thirds, 

 dusky on the third from 

 the tip. The Arctic form 

 has shorter legs. The rare 

 roseate-tern differs from both 

 in having the breast rosy tinted, the beak black, the tail longer, 

 the inner webs of the primaries all white. In autumn all three 

 species have white on the crown and are paler on the under- 

 parts. Fledglings may be easily recognised by their buff- 

 coloured markings. 



Nest. Place : shingle bed, sand with or without vegetation, 

 turf, bare rock, usually near the sea in the British Isles. The 

 nest-scrape may be either unlined or lined with dry grass and 

 other vegetable matter picked up near by, also pebbles, shells, 

 and sometimes rabbit bones. Species breeds in colonies. 



Eggs. More often 3 than 2. Dull greyish, cream or deep 

 buff, blotched and spotted with shades of brown and ash. 

 Rare varieties with blue and red grounds. Av. size, 1*61 x 

 1*19 in. Laying begins end of May to early June. One brood. 



107. Arctic-tern [Sterna paradiscea Brtinnich ; Sterna 

 macrura Naumann]. Summer visitor to our coasts and generally 



Fig. 66. Common-tern's primary. 



