OF THE BRITISH ISLANDS. 97 



to assist in the duty of incubation, which lasts about a month. 

 The bird which chances to be off the eggs is usually placed 

 sentinel-like close by the nest, ready to give the alarm, and to 

 take part in driving off predaceous birds or animals. The 

 Demoiselle Crane appears only to rear one brood in the year, 

 and the young chicks are soon able to leave the nest and follow 

 their parents. 



Diagnostic Characters. — Grus, with the general colour of 

 the plumage pale slate-gray, the feathers of the throat elongated, 

 the tertials long and pointed, but not curled, and a tuft of long 

 white feathers on each side of the head, which is neither crested 

 nor bare of feathers. Length, 31 to 36 inches. 



