I90 THE NESTS AND EGGS OF BRITISH BIRDS. 



the cliffs in which the eggs are deposited being selected 

 ready to hand, or made undesignedly by the old birds 

 whilst incubating. At a nest on the Bass, a few scraps 

 of heather were in the hollow, as well as a feather or 

 so ; but these materials had most probably accumulated 

 there by chance. The Peregrine is not a very close 

 sitter, and when disturbed, often flies to and fro high in 

 the air overhead, chattering loudly in displeasure at the 

 invasion of her fastness. The male bird generally soon 

 joins her. 



Range of egg colouration and measurement : 

 The eggs of the Peregrine are from three to four in 

 number, but sometimes only two, and I have known 

 a nest that contained one solitary chick. They are 

 yellowish or creamy-white in ground colour, thickly 

 mottled, spotted, and clouded with reddish-brown, brick- 

 red, and orange-brown of various shades. The markings 

 are usually so numerous and so confluent, that little if 

 any of the ground colour is visible. A rare variety is 

 suffused with a purplish tinge or bloom. These eggs 

 closely resemble those of the Kestrel in colour, and 

 go through precisely the same variations. Average 

 measurement, 2'0 inches in length, by \'6 inch in 

 breadth. Incubation, performed chiefly by the female, 

 lasts a month according to Macgillivray. 



Diagnostic characters : The large size of the 

 eggs of this Falcon readily distinguish tliem from those 

 of all allied species breeding in the British Islands. 



