ARCTIC SKUA. 



679 



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 hair-like yellow streaks appear 

 on the sides of the neck ; next, the sides of the neck be- 

 come lighter in colour ; and, advancing in age, the neck, 

 all round, becomes white, tinged with yellow, the head re- 

 maining of the same colour as the back. In the pure dark 

 form the underparts continue to be nearly as dark as the 

 back, the acuminate feathers of the neck being of a golden 

 bronze tint, but in examples of mixed parentage some lighter 

 and slightly barred feathers are visible on the lower part of 

 the breast. It is by no means uncommon to find one or 

 more white feathers on the carpal joints. 



