210 ANNALS OF SCOTTISH NATURAL HISTORY 



the coast all the winter. There is one point in connection 

 with this bird and the Common Guillemot which, as I have 

 seen no reference made to it in books, I think of sufficient 

 interest to mention here. When hatching, the Razorbill, as 

 is well known, lies alongside of the egg, whereas the Guillemot 

 sits right over it. Now on each side of the Razorbill, under 

 the wing, is a circular spot about two inches in diameter, quite 

 denuded of feathers, and with the skin round its circumference 

 considerably thickened. The egg is held in this spot by the 

 wing, and must be kept much warmer by coming directly in 

 contact with the skin than would be the case were the feathers 

 to intervene. The Guillemot has a spot exactly similar in the 

 lower third of its breast, in the middle line. These spots must 

 be carefully searched for, even when the birds are in the hand, 

 as the surrounding feathers, which are very thick, completely 

 cover them, which probably is the reason why they have been 

 overlooked. They are found only on the sitting birds, as I 

 have examined several during the breeding season which 

 showed no trace of them. 



I have one Razorbill's egg which is pure white. Two of 

 this colour were got at Barrahead in 1893, at the same spot, at 

 about ten days' interval, and were supposed to have been laid 

 by the same bird. 



COMMON GUILLEMOT, Uria troik (L.) Immense colonies breed 

 in the southern islands, and a few birds remain round the 

 coast during the winter. The bridled variety number about 

 one in five, and are of both sexes, pairing with each other and 

 with the common variety indifferently, as I have frequently 

 observed in the rocks. 



BLACK GUILLEMOT, Uria giylle (L.) This species is moderately 

 plentiful during the breeding season at various localities round 

 the islands. In winter, too, it is not uncommon, although I 

 believe the bulk of those that remain with us are young birds 

 in the grayish white plumage. A few old birds are, however, 

 met with, and these are in the black or summer plumage. I 

 have already in the " Annals " drawn attention to the fact that 

 this Guillemot always retains the black plumage in winter once 

 it has attained it, when about a year or ten months old. I 

 have met with birds in the full summer or black plumage early 

 in February, when the young are in the gray the latter not 

 changing to the black till the beginning of May ; and Mr. Mal- 

 colm Macaulay, the Lighthouse boatman, who knows the bird 

 perfectly well, tells me that he meets with numbers of them 

 every winter in the black plumage, when visiting the Light- 

 house at Barrahead. 



