HORNBILLS are medium-sized or large birds
that live in Asia and Africa, usually in the jungles. Their most
prominent feature is the very large bill, which bears a sizable,
brightly colored, horny growth--the casque. Though the bird has
the appearance of being out of balance, the casque is generally
very light; it is made up of thin-walled hollow cells. The flight
of the hornbill is heavy and sluggish.
The hornbill is famous for its very unusual
nesting habits. Once courtship and mating are at an end, the
female retires to a hollow tree and seals herself into the chamber
with a clay-like substance made up of dung and pellets of mud.
The male gathers these materials on the forest floor and swallows
them. Later he expels them in the form of small saliva-made pellets
which he gives to the female who stays inside the nest. She plasters
them on the sides of the entrance. At last a slitlike window
remains which is just big enough to receive part of the bill.
For the next six or eight weeks the male feeds the female through
this opening. The imprisoned female lays a few white eggs. While
incubating, she begins a complete molt and for a time is flightless,
having lost all her wing and tail feathers.
many hornbills the female breaks her way out of the nest a week
or more before the young are ready to leave the shelter. Dressed
in all-new feathers, she helps her mate feed their young. With
an amazing display of instinct, the babies immediately rebuild
the entrance barrier.
Most hornbills are black and white, sometimes
varied with chestnut or gray. Their legs and feet are short and
rather weak. Most hornbills are fruit eaters. There are some
46 species that make up the family. The red-billed hornbill is
shown at left above.