ndred or more noisy
laughing-thrushes, or numbers of cheeping white-eyes and tits, or
it may be a flock of rowdy black bulbuls. All the birds of the wood
seem to be collected in one place. This flocking of the birds in the
hills must, I think, be accounted for by the fact that birds are by
nature sociable creatures, and that food is particularly abundant.
In a dense wood every tree offers either insect or vegetable food,
so that a large number of birds can live in company without fear of
starving each other out. In the plains food is less abundant, hence
most birds that dwell there are able to gratify their fondness for
each other's society only at roosting time; during the day they are
obliged to separate, in order to find the wherewithal to feed upon.

Like all sociable birds, the black-throated jay is very noisy. Birds
have a language of a kind, a language composed entirely of
interjections, a language in which only the simplest emotions--fear,
joy, hunger, and maternal care--can be expressed. Now, when a
considerable flock of birds is wandering through a dense forest, it
is obvious that the individuals which compose it would be very liable
to lose touch with one another had they no means of informing one
another of their whereabouts. The result is that such a means has
been developed. Every bird, whose habit it is to go about in company,
has the habit of continually uttering some kind of call or cry. It
probably does this unconsciously, without being aware that it is
making any sound.

In Madras a white-headed babbler nestling was once brought to me.
I took charge of it and fed it, and noticed that when it was not asleep
it kept up a continuous cheeping all day long, even when it was eating,
although it had no companion. The habit of continually uttering its
note was inherited. When the flock is stationary the note is a
comparatively low one; but when an individual makes up its mind to
fly any distance, say ten or a dozen yards, it gives vent to a louder
call, so as to inform its companions that it is moving. This sound
seems to induce others to follow its lead. This is especially
noticeable in the case of the white-throated laughing-thrush. I have
seen one of these birds fly to a branch in a tree, uttering its curious
call, and then hop on to another branch in the same tree. Scarcely
has it left the first branch when a second laughing-thrush flies to
it; then a fourth, a fifth, and so on; so that the birds look a