64 THE TERNS 



are more variable in colour and markings than those of the common-tern, the 

 ground-colour ranging from deep rich red-brown through all shades to pale stone 

 colour and light blue. On the average the markings are also richer and bolder, 

 and the average size is rather less, but some undoubted eggs of the common-tern 

 are quite as small and richly marked as any Arctic-tern's eggs. (PI. H.) Average 

 size of 116 eggs, 1*6 x T16 in. [40'8 x 29'5 mm.]. Incubation lasts 20 days accord- 

 ing to Mr. F. G. Paynter, and Naumann states that both sexes brood in turn but 

 the hen alone during the night, though during bright and sunny weather the eggs 

 are left exposed for long periods. Naumann's statement that the incubation 

 period in the case of this species (and also the common- tern) lasts only for 15-16 

 days cannot be relied upon. The breeding season is slightly later than that of 

 the common-tern, and in the British Isles eggs are rarely to be found before the 

 beginning of June or the end of May at the earliest, but on the west coast of 

 Jylland I found birds just beginning to lay on May 12, an exceptionally early 

 date. Only one brood is reared during the season. [F. c. B. J.] 



5. Food. Small fish, small floating crustaceans, insects and their larvae, earth- 

 worms. Mr. H. C. Hart, in his account of the " Ornithology of the British Polar 

 Expedition, 1875-76" (Zool, 1880, p. 206), states that at Musk Ox Bay, at 81 45' 

 N. lat., their " chief food was green caterpillars " (Argynnis chariclea and the 

 larvae of Tipula arctica). The young are fed by both sexes, chiefly on small fish, 

 and sometimes on earth-worms and insects. An instance of the species feeding its 

 young on crane-flies, greendrakes, and May-flies is given in British Birds, iii. 91, 

 by Mr. Wm. C. Wright and on earth-worms by Mr. J. Tomison in the Annals 

 of Scottish Natural History, 1904, p. 23. [F. B. K.] 



ROSEATE-TERN [Sterna dougdlli Montagu. French, sterne de Dougatt ; 

 German, Dovgalls-Seeschwalbe ; Italian, rondine di mare del MacDougatt]. 



I. Description. The roseate-tern bears a close likeness to the common- 

 tern, from which, however, it may be distinguished by the long and slender black 

 beak, the relatively shorter wings, wherein the inner webs of the primaries are white 

 to the tips, the relatively longer and more deeply forked tail, and the rosy-tinted 

 breast. There is a scarcely perceptible seasonal change of coloration, and the sexes 

 are alike. (PI. 101.) Length 15 -5 in. [393-69 mm.]. The adult, in summer dress, has 

 the top of the head and nape black, the pearl-grey of the upper parts paler than in 

 the Arctic and common terns. The white inner margins of the primaries extend to 



