GULL-BILLED TERN. 



267 



inch). The general colour of its plumage and the successive changes 

 which it undergoes are typical of the group to which the Arctic Tern 

 belongs ; but in this species the dark bar across the lesser wing-coverts in 

 the immature bird is absent, and the head of the adult after the autumn 

 moult is white, with grey and black streaks which extend to the upper ear- 

 coverts. Bill black ; legs and feet reddish black ; irides hazel. 



Young in down have the upper parts pale butf, mottled with dark grey, 

 and the underparts dull white. 



