BRITISH BIRDS. 
25 
the secondary quills, which are white; all the under 
parts, from the chin to the vent, are also white ; the 
legs black. From the similarity in some of the mark- 
ings of these birds and of the Razor-bill and Foolish 
Guillemot, ornithologists have been led to consider 
them as varieties of the same species ; but this opinion 
Mr Montagu combats, we think, very successfully. 
He has treated largely on this subject, and is satisfied 
that they are distinct species. The Razor-bills and 
Foolish Guillemots mostly leave the arctic regions, to 
breed and rear their young in more southern climes, 
and for that purpose, in the summer months, are seen 
in flocks of immense numbers, on the rocky promonto- 
' ries and isles of the British shores, which they leave in 
the autumn. The Black-billed Auks and lesser Guil- 
lemots, on the contrary, remain to breed, also in im- 
mense numbers, in Iceland, Greenland, &c. in the 
continued day light of summer, and disperse south- 
ward on the approach of the winter cold, and dark- 
ness of the frigid zone. 
