Evidence is presented to show that the coastal species Pteropus poliocephalus and P. gouldi congregate in large camps from early until late summer. In these large summer camps the young are born and raised, the sexes become associated, and conception occurs. The numbers within these camps are influenced by the availability of blossom in the surrounding area. The adults are normally dispersed during the winter while the immature form winter camps. These camps contain a larger percentage of adults in those winters in which blossom is more abundant. The inland species P. scapulatus forms large camps in early summer but the young are born in autumn when the population is dispersed. Since the food supply of P. scapulatus is less dependable and undergoes greater fluctuations than that of the coastal species, P. scapulatus is more nomadic than P. poliocephalus and P. gouldi.