males arrive in breeding sites before females, and establish their territory. a territory can consist of several potential nest sites. after forming a pair, both the male and female inspect available nest sites. this process is complicated by the fact that artificial nest sites could be houses with many rooms, clustered gourds, or single gourds. the nest is made inside the cavity of such artificial structures and retains a somewhat flat appearance. the nest is a structure of primarily three levels: the first level acts as a foundation and is usually made up of twigs, mud, small pebbles and in at least a few reported cases, small river mollusk shells were used; the second level of the nest is made up of grasses, finer smaller twigs; the third level of construction composing the nest, is a small compression usually lined with fresh green leaves where the eggs are laid. three to six eggs are laid, and the female is the main incubator, with some help from the male. purple martins are generally known to raise only a single brood. fledging, when the young leave the nest, occurs at about one month, after which the parents continue to feed the fledgling young.