236 FIELD-STUDIES OF RARER BIRDS 



is white), which its congeners do, sometimes to no 

 small extent (but of course through friction), during 

 the period of laying and incubation. Although a 

 pellet or so is occasionally cast in the eyrie by the 

 old Falcons, no layer of them is ever seen under 

 the eggs, as is the customary habit of the Kestrel, 

 once its incubation has fairly started. 



When on a longish ledge the eyrie is generally 

 placed in about the middle of its broadest part ; 

 sometimes, however, the shelf selected is only 

 just a size larger than the eyrie itself, while occa- 

 sionally it is so insignificant that the scrape for the 

 eggs has perforce to be considerably smaller than 

 its wont. Moreover, a very casual Falcon, tem- 

 porarily bereft of all common sense, will actually 

 lay on such a sloping platform that one or more of 

 its eggs have rolled off ; sometimes, too, even in 

 a normal eyrie, th,e bird will kick or scrape 

 an egg out of the site. I remember one 

 such instance where the shelf selected by a 

 pair was of an extremely rough character, 

 being littered and encumbered with some big and 

 half-detached lumps of chalk. In their com- 

 mendable zeal in removing these blocks the first 

 egg was knocked out of the eyrie, and I found it 

 reposing in a chink of some debris to one side of 

 the ledge, only a foot or so lower down the cliff. 

 Curiously enough, it was not even dented, and at 

 the time I found it the Peregrine was complacently 

 sitting on the empty eyrie as the species often 



