GULL- BILLED TERN. 535 



lighter ; the outside web of the first primary slate-grey, the 

 other primaries pearl-grey, darker at the tips ; chin, throat, 

 breast, belly, and all the under surface white; legs, toes, 

 membranes, and claws reddish-black. The whole length of 

 the bird figured and described, fifteen inches and a half; 

 wing from the carpal joint thirteen inches. 



In winter the head is white, streaked with grey and 

 black, and a dark stripe runs through the eye and ear- 

 coverts. 



The male is, as a rule, rather larger than the female, but 

 there is great individual variation in size, especially as 

 regards the bill. In the latter the difierence is more strik- 

 ing in two individuals shot from the same flock in South 

 Brazil than in any other specimens in the large series which 

 the Editor has examined from various parts of the world. 



A young bird of the year has the bill brown ; head on the 

 top dull white, varied with pale brown and dusky streaks ; 

 on the ear-coverts a spot of greyish-black ; neck all round 

 white ; back, scapulars, and tertials orange-brown, spotted 

 with darker brown ; wing-coverts ash-grey, tipped with pale 

 orange-buff ; primaries pearl-grey ; tail but little forked ; 

 chin, neck, and all the under surface of the body white ; legs 

 and feet brown. As in the other Terns, the orange-buff 

 markings are soon lost, and in this species there is no dark 

 bar on the carpal joint to indicate immaturity ; the bill and 

 legs are, however, lighter than in the adult in winter dress. 

 Even in birds of the second year which have assumed the 

 black crown, the legs and feet are still livid red in fresh 

 examples, drying a reddish-brown in preserved specimens. 



The nestling in down is bufiy-white, mottled and striped 

 with darker grey on the upper parts ; under parts greyish- 

 white. 



