THE BLACK GUILLEMOT 303 



grounds affected by the two colonies decided 

 the matter. 



The eggs are rather blunt, and, though their 

 layers are considerably smaller than the Common 

 Guillemot and Razorbill, even so are they small by 

 comparison with the egg of either of those two 

 species. In ground-colour they range from pale 

 greenish white to creamy white and even buff, 

 blotched, spotted, and speckled with dark brown 

 (on some specimens it is almost black), reddish- and 

 yellowish-brown, with underlying markings of grey 

 and lilac-grey. Most eggs are thickest marked at 

 their larger end, and usually a heavily blotched type 

 shows a great deal of ground. One variety is 

 thickly zoned at either end with very dark reddish- 

 black, another is minutely and evenly speckled and 

 freckled with grey, showing only two or three spots 

 of brown, a third is smudged or blotted with 

 irregular daubs and splashes of vivid brown, whilst 

 a fourth is elegantly diversified with spots of dark 

 brown, fawn, and grey. As a rule the two eggs 

 are rather different in the pattern of their mark- 

 ings, though not in the ground tint. Their inner 

 membrane is of a beautifully clear green, their 

 yolk of a vivid reddish-chrome. They are not 

 always deposited on successive days, while 

 incubation, the task of both sexes, lasts about a 

 lunar month. 



While it is a fact that, when the chosen cavity 

 penetrates the cliff some distance, the sitting bird 



