BIRDS OF THE BRITISH ISLES. 379 



(5uU=billeb TLcvn. 



c/o/VA^a/YCAyV, 



The Gull-billed Tern {Sterna a7igUca^ Montagu) is a rare 

 straggling spring and autumn migrant to the British Isles. 

 It inhabits the Southern Palearctic and Nearctic Regions. 

 The adult male in nesting plumage has the forehead, crown, 

 and back part of the neck, rich deep black ; upper parts, 

 pearl-grey; primaries, greyish; under parts, white; irides, 

 brown ; bill, stout and black ; legs and feet, black. Length, 

 from fourteen to fifteen inches. The adult in winter has 

 the forehead and crown white, with grey streaks ; ear- 

 coverts, patched with grey. The young on upper parts are 

 more or less marked with various shades of brown ; under 

 parts, white ; legs and feet, brownish. 



