BIRDS OF GUERNSEY. 197 



the little island of Burhou, which has heen entirely 

 appropriated by the Lesser Black-backs ; in all 

 these places the Herring Gulls and Shags take almost 

 entire possession of the rocks, the Lesser Black- 

 backs apparently never mixing with them ; indeed, 

 except a chance straggler or two passing by, a Lesser 

 Black-back is scarcely to be seen at any of these 

 stations. The Herring Gull and the Lesser Black- 

 back, though very distinct in their adult plumage, 

 and even before they fully arrive at maturity, as 

 soon as they begin to show the different colour of 

 the mantle, which they do in their second autumn, 

 when a few of either the dark or the pale grey 

 feathers appear amongst the brownish ones of the 

 young bird, are before this change begins very 

 much alike. In the down I think they are almost, 

 if not quite, indistinguishable after that in their 

 first feathers, and up to their first winter they 

 appear to me distinguishable. As far as the 

 primary quills go I do not see much difference ; the 

 shafts, perhaps, of the quills of the Lesser Black- 

 back are darker than those of the Herring, but the 

 difference if anything is very slight ; but the head 

 and neck and the centres of the feathers of the 

 back of the Lesser Black-back are darker, more 

 of a dark smoky brown than those of the Herring 

 Gull : this difference of colour is even more apparent 

 on the under surface, including the breast, belly, 

 and flanks. The shoulder of the wing and the 



