THE WORLD'S BIRDS. 



175 



some. Tongue very long and extensible, hard 

 and barbed at tip. 



PLUMAGE AND COLOURATION. Varied in colour, very 

 commonly black and white, sometimes olive-green, 

 or brown, never showing any blue, but very often 

 red or yellow ; no seasonal change, but usually a 

 small difference between the sexes. Young differing 

 little from parents ; sex-difference apparent at once. 



YOUNG. Naked and helpless, fed by parents ; they have 

 bare, swollen skin at the gape, and a warty pad 

 on the hock, as nestlings, and move about in the 

 nest on their hocks. 



NEST. A hole pecked out in a tree or bank. 



EGGS. Several, pure glossy white. 



INCUBATION. A fortnight, or a little more. 



COURTSHIP. In the American Flicker (Colaptes auratus] 

 the male displays his wings. 



FOOD. Chiefly insects, especially wood-borers and 

 shelterers under bark ; berriesj fruit, nuts, and 

 sometimes the sap of trees, are also taken by 

 some. They usually seek food on trees, but some 

 feed on the ground. 



GAIT. On the ground they hop awkwardly, but on 

 the trees they are very active, seldom hopping 

 from bough to bough, but climbing up and round 

 the trunks and large branches ; they descend, if 

 at all, tail first. 



FLIGHT. Usually somewhat undulating, a few beats 

 of the wings alternating with closure of them for 

 a moment. The feet are carried tucked up in 

 front, and the neck extended. 



NOTE. Usually harsh, a cackle or " laugh " ; some- 

 times a piping sound. 



DISPOSITION AND HABITS. Shy unless protected, un- 

 sociable as a rule, and often rather quarrelsome. 

 Young birds in some cases will fight violently as 

 soon as fledged. 



