COMMON GUILLEMOT. 311 



to the sea w1ien disturbed, and returning as soon as its 

 haunt is left in peace. It utters little or no sound when 

 thus disturbed. 



Range of egg colouration and measurement: 

 The Guillemot lays only one egg, but if this be taken it 

 is usually replaced several times in succession. It is 

 impossible, even with much more space than we here 

 have at our disposal, to describe a tithe of the variations 

 in colour and character of markings in the eggs of this 

 species. In no other known bird do they vary so widely ; 

 and certainly the eggs of none are more beautiful. The 

 ground colours of the ^^^ (which is pear-shaped) are 

 dark green, yellowish -green, reddish -brown, cream- 

 yellov/, white, and pale blue, with every intermediate 

 shade ; the markings, which take the form of spots, 

 blotches, streaks, and zones, are composed of browns 

 and grays and pinks of every possible tint. Some eggs 

 of course are much handsomer than others ; some are 

 without markings of any kind. An exquisite variety 

 is white, intricately streaked and netted with pink ; 

 another is green, streaked in the same manner with 

 yellow, light brown or nearly black ; others are zoned 

 with blotches, or marked with fantastic-shaped spots and 

 rings. Average measurement, 3"3 inches in length, by 

 2"0 inches in breadth. Incubation, performed by both 

 sexes, lasts from thirty to thirty-three days. 



Diagnostic characters : The (tg^ of the Guillemot, 

 in spite of its wonderful variation, cannot readily be con- 

 fused with that of any other species, except that of the 

 Razorbill. Eggs, however, that resemble those of the 

 latter bird may be at once distinguished by holding 

 them up to the light and looking at the interior of the 

 shell through the hole where they have been blown, when 

 the colour is yellowish-white, never green. See also 

 diagnostic characters of the egg of the Razorbill (p. 315). 



