700 A PRACTICAL HANDBOOK OF BRITISH BIRDS. 



and crown more heavily streaked black ; upper-parts and especially 

 scapulars duller grey not so silvery as adult ; tail-feathers dull grey, 

 tipped greyish- white, outermost mostly white but grey on inner 

 webs near tip ; outer primaries not quite so silvery as adult and 

 darker on inner webs ; secondaries and lesser-coverts darkish grey 

 in centres. N.B. — Some appear to moult in 1st summer into a 

 plumage like adult summer except for some dull grey on tail- 

 feathers and secondaries. 



Measurements and structure. — $ wing 398-425 mm., tail : outer 

 feather 135-150, central 98-110, depth of fork 30-45, tarsus 45-47, 

 bill from feathers 64-72 (10 measured). 9- wing 400-425. Primaries : 

 1st narrow, pointed, and about two -thirds primary-coverts, 2nd 

 longest, 3rd 15-20 mm. shorter, 4th 40-48 shorter, 5th 70-80 shorter. 

 Rest of structure as in Gull-billed Tern but tail comparatively less 

 forked, rather more of tibia bare, bill very stout and deep and 

 gonys comparatively shorter. 



Soft parts. — Bill (ad.) rich coral-red, (juv.) paler, tipped dusky ; 

 legs and feet black ; iris dark brown. 



Characters. — H. c. strenua (Australia) has been described as hav- 

 ing a deeper bill, but this is not a constant character. Very large 

 size and very large, stout, deep, red bill distinguish this from all 

 other British Terns. 



Breeding-habits. — Nests in colonies on low-lying, sandy islands 

 or shores. Nest. — Mere hollow made by bird in sand. Usually 

 nests are only a couple of feet or so from one another and colonies 

 are sometimes of considerable size. Eggs. — Normally 3 in Black 

 Sea, occasionally 2 only, but Rohweder says 2 is normal clutch in 

 List and 3 exceptional. Colour stone -buff, blotched and spotted 

 rather sparinglv with blackish-brown and ashy shellmarks . Average 

 of 100 eggs, 64x44.4. Max. : 72.3x44.5 and 65x46.5. Min. : 

 55x40.5 mm. Breeding -season. — Second half May in central 

 Europe, and in June in Gulf of Bothnia. Incubation. — Probably 

 shared by both sexes but information defective. Period about 

 20 days. Single brooded. 



Food. — Mainly fish, especially those of genus Clupea, though 

 Pleuronectes and Scomber also recorded. Occasionally eggs and 

 young of other birds taken : half grown Lapwing ( Vanellus vanellus) 

 found in stomach (Schilling). 



Distribution. — England. — Very rare vagrant. About twenty- 

 three obtained and others seen : Northumberland, Yorks., Lines., 

 Suffolk, Hants, (one each), Sussex (two), Kent (two and others doubt- 

 ful), Notts, (two), Dorset (four), Norfolk (nine got and others seen,, 

 the last July, 190L July, 1902, Aug., 1910, and May, 1918). 



Distribution. — Abroad. — Locally on coasts of Europe from about 

 60° north lat. southwards (Baltic, Sylt, Mediterranean, Black and 

 Caspian Seas) ; throughout Asia east to China, Malaysia to Australia 

 and New Zealand ; many parts of Africa, chiefly in winter ; also 



