392 CORACITFORMES CHAP. 
from their bulk are restricted to the stronger branches, along which 
they shuffle awkwardly, even assisting themselves with their beak. 
Hornbills may be met with singly or in pairs, but ordinarily 
form parties of five or six, if not of larger numbers, gathering 
together to feed or to roost at fixed spots, which they leave before 
sunrise. They are not naturally shy, and if disturbed only resort 
to some neighbouring tree, where they may be often observed 
sitting on the boughs during the mid-day hours, with puffed out 
plumage, open bill, and head sunk upon the back as if overcome by 
the heat. From time to time while perched they elevate or depress 
the crest and utter loud yelping cries, not uncommonly flapping 
their wings and bowing their heads; when feeding they con- 
stantly chatter in chorus like Parrots, and vanish with shrill 
screams if intruders appear. The characteristic note, however, is a 
harsh, continuous sound, intermediate between the bray of an ass 
and the shriek of a railway engine; that of Bucorvus abyssinicus 
has been sylabled “ hum-hum,” and that of 2. cafer, the “ Brom- 
vogel” of South Africa, has been said to resemble a lon’s roar, 
and to be audible for a mile. All the species are apparently 
most noisy in the morning and evening, or before rain. 
Fruits and insects—the latter occasionally hawked for in the 
air—constitute the normal food, but the larger forms devour small 
mammals, birds, eggs and reptiles, with grubs, flowers, and young 
shoots; while Bucorvus, which feeds chiefly upon the ground, 
and hops rapidly, will eat tortoises, mandioc-roots, and so forth. 
Berries of Strychnos and figs seem greatly in favour. Nearly 
everything is swallowed entire, with a backward jerk of the head, 
animals having the life beaten out of them previously, and most 
substances being tossed up into the air. The male has a most 
curious habit of casting up the lning of the gizzard with its 
contents enclosed, possibly to feed the female or young.' 
A hole in a tree or a cavity at the junction of two branches 
serves for the nest, wherein the hen is enclosed by a plaster of 
dung or like material; there, under penalty of death, she remains 
until she emerges dirty, wasted and enfeebled, when the brood 1s 
hatched. From one to four dingy white eggs with coarse pores 
are deposited upon the débris or a few feathers. Contrary to 
expectation, observations seem to shew that the female walls 
herself in; but, however that may be, the cock feeds her through 
1 A.D. Bartlett, P.Z.S. 1869, p. 142 ; Flower, tom. cit. p.150; Murie, op. cit.1874, p.420. 
