THE WORLD'S BIRDS. 63 



Feet with shanks usually very short (long only in 

 the Ground Hornbills), and the two outer front toes 

 united ; hind-toe well-developed. Wings with short 

 primaries, but large altogether, having the upper - 

 and fore-arm bones long, as in many water-fowl; 

 tail long, rounded or wedge-shaped ; head large, 

 neck long, body meagre ; thighs very prominent. 

 Tongue very short. 



PLUMAGE, COLOURATION, ETC. Usually sombre, though 

 strongly contrasted ; black and white, sometimes 

 grey, and sometimes partly chestnut. Sexes some- 

 times different, and young also differing at times. 

 Bill and bare face often richly coloured. Upper 

 eyelid furnished with eyelashes. 



YOUNG. Helpless, naked, and fed by parents. The 

 casque or " horn " does not appear till some time 

 after they are fledged. 



NEST. In most cases simply a hole in a tree, walled 

 up by the female with her own dung, till only a 

 slit is left, through which the male feeds her and 

 the young. The Ground Hornbills, however, build 

 an ordinary nest in a fork. 



EGGS. One or two only ; white and spotless. 



COURTSHIP. Little known ; in the Ground Hornbills 

 the throat-wattle is expanded, the wings drooped 

 and tail raised. 



FOOD. The short-legged tree-haunting species live 

 mostly on fruit, and such small animals as they 

 can capture ; the ground-living forms subsist mainly 

 on the animal diet. They hardly ever drink, and 

 show little inclination even to bathe. 



GAIT. The tree species, which usually seldom visit the 

 ground, move there by awkward hops ; they also 

 hop sideways along the boughs ; the ground 

 species walk and run freely. 



FLIGHT. Heavy, and in the large species noisy, per- 

 formed either by continued flappings or by alternate 



