THE RAZORBILL AND GUILLEMOT 13 



THE RAZORBILL AND GUILLEMOT 



[F. B. KIRKMAN] 



In the older classifications the Auks were placed next to the 

 Divers (Colymbidce). A closer study of their structure has revealed 

 the fact that, like the Gulls and Terns (Laridce), they are a highly 

 specialised form of the Plovers (Limicolce). They are descended from 

 some primitive plover that left the shore for the sea, the change from 

 one habitat to the other being accompanied by a change in structure, 

 which, by a process of convergent evolution, has led to their present 

 resemblance to the divers, more particularly in respect to modifica- 

 tions tending to increase their powers of movement in the water, such 

 as the lengthening of the body and the shifting back of the legs to its 

 posterior end. 1 



The family is confined to the northern hemisphere. Of some 

 twenty-five species, the names of seven find a place on the list of 

 British birds. One of these, the great-auk, is extinct; a second, 

 Briinnich's guillemot, is a very rare occasional visitor ; and a third, the 

 little-auk, a fairly common winter visitor. The remaining four species, 

 the black-guillemot, puffin, and those which form the subject of this 

 chapter, are to be found on British waters all the year round. All 

 four belong to different genera, but the frequent association of the 

 razorbill and common-guillemot makes it convenient to treat both 

 together. 



The two species are not difficult to distinguish, even apart from 

 the marked difference in the shape of their bills. 2 The razorbill is a 

 handsome bird, its rich black upper parts gaining an added effect in 



1 H. Gadow in Bronn's Thier-reichs, vol. vi. ; Vogel, II. Systematischer Theil, p. 206 ; 

 P. E. Beddard, Structure and Classification of Birds, p. 359 ; W. P. Pycraf t, History of Birds, 

 pp. 55, 450. 



* What there is in the shape of the bill of the razorbill to justify its name I am unable to 

 understand. 



