In the wild, the preferred nesting site for the Budgerigar (Melopsittacus undulatus) are tree hollows and logs. In the northern parts of Australia, breeding usually takes place between June and September, whilst in the southern parts of Australia, breeding takes place between August and January. They are however opportunistic breeders responding to rains and the appearance of abundant grass seeds.
With the availability of water, populations are found to increase. During breeding they lay between four to six eggs , with incubation being 18–21 days. The young fledge in about 30 days after hatching.