A large number of birds of several species display a kind of behavior in the evening which is worth watching. They take frequent shot flights and settle down on trees or wires, etc. The settling down of birds for rest at night on elevated places is called roosting. While doing so they make a noise. This is a preparation for their rest at night. All those diurnal birds i.e. those that are active during the daytime need rest at night. Nocturnal birds i.e. those that move around in the night for food, etc., roost during daytime. Owls are nocturnal.s the roosting pattern of birds is different for different species.
Koel roosts singly, bulbuls roost in small groups, but mynas roost in very large numbers. Community roosting can also be seen wherein mynas, house crows, jungle crows, and parakeets, etc., roost on the same tree. Community roosting offers three advantages. (1) Members of the roost, while sharing the same platform, receive the warmth of togetherness. (2) There are always a few members of the roost who are more alert than others. In this way they act as guard of sentry in the event of any advancing predator or enemy. (3) Communal roosting allows the transmission of information regarding a source of food for all of them. Thus the roosting place is thought to be a centre for information brought in by a particular bird to be passed on to others.