Richardson's skua. 493 



longer than tlie others ; neck in front, breast, belly, and 

 under tail-coverts pale yellowish wood-brown, mottled and 

 transversely barred with umber-brown ; legs, and the base 

 of the toes yellow, the ends of the toes and the anterior por- 

 tion of the intervening membranes black, and hence called 

 sometimes the Black-toed Gull; but this is only an indication 

 of youth: as the bird increases in age the yellow colour is lost 

 by degrees. 



The next stage, which in this species, also, as in the Poma- 

 rine Skua, probably occurs in the second year, the plumage 

 is of a uniform greyish umber-brown, the whole of the light 

 brown margins having disappeared, and the bird has now 

 acquired its full size, measuring from the point of the beak to 

 the end of the long feathers of the tail twenty inches, the 

 central pair of tail-feathers being three inches longer than the 

 next feather on each side ; the wing, from the anterior bend 

 to the end of the longest quill-feather, thirteen inches and 

 three-quarters ; the tarsus one inch and three-quarters ; the 

 middle toe and claw together the same length, or one inch 

 and three-quarters. 



After this stage a few yellow hair-like streaks appear on 

 the sides of the neck ; next, the sides of the neck become 

 lighter in colour ; and, advancing in age, the neck all round 

 becomes white, tinged with yellow, the head remaining of 

 the same colour as the back. Males and females are not dis- 

 tinguishable by their plumage, and as this species, like the 

 smaller Gulls, is capable of breeding when one year old, it 

 is observed, that birds, sometimes in similar states, and some- 

 times in very different states as to plumage, are in pairs at 

 the breeding-stations. 



