268 THE STORY OF THE BIRDS 



in circles about a yard from the apex, where 

 the generating heat hatches them. It is 

 rather remarkable that one of the Coursers — 

 the Cursorius aegyptius of ornithologists — re- 

 sorts to similar methods of nidification, burying 

 its eggs in the sandy banks of the Nile, where 

 they are at least partially hatched by the sun. 

 Incidentally we may also mention that not a 

 few other and more familiar birds partially 

 invoke similar aid ; for many of the shore birds 

 — such as Gulls, Terns, and Plovers — rarely sit 

 upon their eggs during the hottest hours of 

 the day ; whilst the Grebes and some of the 

 Rails derive considerable assistance in the task 

 of incubation from the fermentation of the 

 aquatic vegetation with which they construct 

 their often floating raft-like nests. It is possible 

 that the dense bed of down which the Ducks 

 and Geese, &c., provide for their eggs may 

 materially assist in preventing loss of heat, 

 especially in high latitudes, but that it also 

 serves to conceal them during the parent's 

 temporary absence seems to us unquestionable. 

 Were it not for this precaution the very con- 

 spicuous eggs would soon fall a prey to maraud- 

 ing birds and animals. Another exceptionally 

 curious type of nest is made by the Flamingoes. 



