BLACK-BILLED AUK. 



41 



the same species, we must conclude that both old and young change 

 their plumage in winter. This, however, is highly improbable ; it is 

 more likely that the singular line in the mature razor-bill, running 

 from the bill to the eye, never varies, but forms the characteristic dis- 

 tinction of the species. 



A variety of this species was shot in January, and another in 

 February, 1802, the examination of which served still further to con- 

 firm our opinion that they form a distinct species : the first weighed 

 from sixteen to seventeen ounces ; the furrow at the base of the bill 

 white ; the base of the upper mandible to the eye was an obscure bar 

 of white feathers ; sides of the head, behind the eyes, and round the 

 nape, dingy white ; forehead and crown black ; sides of the chin speckled 

 dusky, with feathers of the throat white, slightly tipped with dusky ; 

 the upper part of the body and wings black ; neck, breast, and upper 

 part of the belly slightly tipped with sooty brown, which gives the 

 feathers a dirty greyish appearance : the other weighed twenty ounces ; 

 length sixteen inches ; breadth twenty-eight inches ; bill furrowed, with 

 one white line across each mandible on each side ; inside of the mouth 

 yellow ; irides hazel ; quills about sixteen in number ; the first eleven 

 all black ; the remainder tipped with white ; from bill to eye an obscure 

 line of speckled feathers ; legs white. A third specimen, killed in 

 February, 1808, was without the furrows on the bill, and also the white 

 line between the bill and the eye : the trachea in this species is rather 

 compressed ; the last ring at the divarication very firm and bony. 



We might conclude, from the variations in the above descriptions, that 

 all the intermediate stages between this species and the razor-bill might 

 be traced ; but this is not the case : the weight of this bird is invariably 

 much less, and the head and neck are never observed to possess that 

 rusty hue which characterizes the razor-bill in all seasons. It is also 

 invariably observed to have, from its nestling plumage to the time of 

 its autumnal migration, the head and upper part of the neck dusky. 

 There are, however, stronger marks of distinction observable in their 

 habits, to which we attach more importance. Fabricius tells us that 

 these birds are more plentiful in Greenland during the breeding season 

 than the razor-bill, and that they disperse in winter towards the south. 

 If, then, this were really the young razor-bill, we might expect that 

 these imperfect birds would appear amongst our swarms of razor-bills 

 during the summer : this, however, is not the case, for out of the thou- 

 sands shot on the coast of England during the breeding season, this 

 species has never occurred to our knowledge. Having such high au- 

 thority for believing that this species inhabits Greenland in great num- 



