[Illustration]
Birds get their everyday names in a variety of ways in the countries
where they live; from their looks, like the snake birds and the pond
scroggins; from their color, like the cardinal and the blackbird;
from their behavior, like the frigate bird and the creepers and the
boobies and king-birds; from what they eat, or are supposed to eat,
like the antbirds and plantain eaters and bee eaters; from what they
say, like the poor-will and the more-pork; from how they say it, like
the warblers and the screamers; from how often they say it, like the
brain-fever bird and the wideawake terns; from where they nest, like
the cliff swallow and the house martin and the chimney swift; and some
from their non-bird associates, like the cowbird, moose-bird, and the
monkey bird.
It is the monkey birds that have taken our fancy at the moment. The
forests of Africa, the jungles of Borneo, and the forests of the
Philippine Islands each have a bird that associates so often with
monkeys that this habit became incorporated into its local name. The
birds are not at all closely related. One is a hornbill, one is a
drongo shrike, and one is the fairy bluebird. The hornbill goes in
parties of their own kind, but apparently the drongo, and certainly the
fairy bluebird prefer the society of monkeys to that of their own kind.
The stories we have of them stress the utilitarian aspect of the
association; that the monkeys as they travel about through the trees
scare insects out of their hiding places and the birds, being on hand,
can snap up the insects more easily than if they had to search them out
for themselves.
The monkey bird in Africa, which is a hornbill, follows, along below
the monkeys in the lower branches of the trees. It used to be thought
this was for the fruit the monkeys dropped, but then it was found the
hornbills were insectivorous. Instead of being scavengers the hornbills
are using the monkeys to beat out their game for them.
Hamba Kerah, the slave of the monkeys, is what the Malays of Borneo
call the racket-tailed drongo. This is from its habit of stationing
itself behind a band of monkeys traveling through the forest. But Mr.
Ridley, who watched them, decided it was the other way around; the
monkeys, unwittingly of course, were working for the drongo, acting as
beaters to drive out the insects which the bird snapped up in the air.
In the Philippines it is "the sentinel of the monkey" that is applied
to the fairy bluebird. The bluebird seldom associates with its own
kind, but is almost invariably associated with a band of crab-eating
macaques. But here again it seems the monkeys are acting as beaters for
the bird, driving out insects.
This is a sort of unconscious co-operation one finds in the bird world.
One animal helps out another without being aware of it. Birds are ever
ready to profit by such behavior, and when it proves of enough benefit,
the habit can become usual for the species, as in the cowbird-cow
relationship, or indispensable as with the oxpecker-hoofed-animal
association.