Description

A large part of the time and energy of the members of every species of bird is taken up in reproducing themselves. This recurring process involves a number of steps, each of which varies considerably among different groups.The breeding season begins in the late winter or early spring for many birds; others may nest at any time, depending on local conditions.
Australia is a country characterized by irregular aridity. The annual cycle of birds is flexible enough to cope with this unpredictability. Bad seasons may see little or no attempt at raising young; good conditions may trigger multiple broods being reared in succession.Birds are dependent on a supply of water, as are the plants and animals on which they feed. In the arid parts of Australia, the presence of water is not always predictable. In order to breed, arid zone birds must move to more favourable areas. Movements are irregular and
have no definite pattern. This behaviour, known as nomadism, characterizes a number of Australian birds.When conditions and seasons are suitable to stimulate breeding,males and females pair up for whatever duration is typical of the species. This pairing is usually preceded by a period of courtship, in
most species initiated by the male. Courtship may be brief and perfunctory or may go on for days with considerable expenditure of energy.Elaborate displays, erection of specialized feathers, proffering of gifts,mutual preening and aerial acrobatics are some methods used to attract a mate.The length of the resulting pair bond may vary from only a few moments to a lifetime, the most frequent being for the duration of the
breeding season. The majority of species are monogamous, that is, one male and one female pair for breeding. In some brightly coloured birds,such as bowerbirds, the male is promiscuous and attempts to mate with as many females as possible. A few groups of birds have the opposite arrangement, one female having several mates. Species with a long
pair bond display throughout the season, strengthening their ties.The male and female often co-operate in the building of the nest.One may gather material while the other puts it together or both may
do the actual construction. In some species, nest building is the task of
only one sex. The nest itself may be very complex or almost non-existent; some species do not bother with one at all. Ground-nesting birds make little more than a shallow scrape in the soil.