184 British Birds, 



sea, and in dry sites. The Black Tern, however, 

 selects marshy places and often builds in very wet 

 spots, making a nest of flags and grass. The eggs are 

 sometimes four in number, this being the only Tern 

 which lays more than three. They vary much in 

 colour and markings, some being of a palish green, 

 others of a brownish yellow, or dull buff, but all 

 spotted and blotched with deep brown. — Fig. 6, 

 plate XL 



WHITE-WINGED BLACK '^Y.^l^—^Hydrochelidon 

 leucoptera ; formerly, Sterna leucopterd), 

 "A rare straggler." 



WHISKERED 'Y^^'^—{Hydrochelidon hyhrida ; 



formerly, Sterna leucopareid). 

 Like the last. 



GULL-BILLED HW^^— {Sterna Anglica). 



Of more frequent occurrence than either of the 

 two last; and especially in Norfolk. 



CASPIAN T^-K^— {Sterna Caspia). 



It may be remarked in connection with the birds 

 we are now among, that the Grebes, Divers, Cormor- 

 ants are all gifted with wonderful powers of diving ; 

 the Gulls and Terns are incapable of diving an inch. 

 The latter, buoyant and sitting as lightly on the water 

 as a cork ; the former deep-sunken in the water, and 

 seeming to require almost an effort to support them- 

 selves on the surface at alL The contrast is certainly 



