340 
EASTERN ETHIOPIA 
xxviir 
The Ibis is generally found along the shores of lakes 
and rivers, hunting for shell-fish, worms, and crabs : it 
also frequents mud-banks, probing tlie mud with its 
long bill. In Lower Egypt the shape of the beak has 
won for this bird the name of “ Father of a Sickle.” It 
is common around the margins of lakes and the banks 
of the Nile in the Equatorial Provinces. (See p. 178 .) 
Hornbills are abundant in Uganda and in the Mau 
forests, and are sure to attract attention from the most 
casual observers, for they are big birds with great beaks 
of curious shape, fiy in a clumsy manner, and make 
a great noise in the forest. The natives do not eat 
these birds and as their black and white plumage is 
not attractive, hornbills are common and force them¬ 
selves on the attention of travellers. In spite of the 
size of the beak the hornbill shows great dexterity in 
using it, for almost every morsel of food it picks up 
is tossed in the air, caught, and swallowed. The neat¬ 
ness with which these birds can catch with the beak 
may be tested any day at the Zoological Gardens, and 
the birds often hold a grape in their beak by means 
of its thin stalk. In the wild state hornbills live 
on fruit, flowers, berries, insects, eggs, and probably 
many other things. 
As if to atone for the heavy and apparently clumsy 
structure of hornbills. Nature seems to have done her 
best to make amends by lightening the heavy beak, for 
she has filled it with air-cells. It is well-known that, in 
Ifirds, the air-cells of the lungs communicate with 
cavities in some of the bones; such bones are said to be 
pneumatic ; in the hornbills more bones are filled with 
air than is common in birds ; air also permeates the 
muscular interspaces and the subcutaneous tissues. 
These birds are devoid of fat beneath their skins. In 
many birds there is a curious gland near the root of 
the tail, known as the oil-gland. When birds preen 
themselves they are supposed to dip their beaks into 
this natural pomatum pot and rub it over their feathers. 
