Tree cavity-using wildlife and the potential of artificial nest boxes for wildlife management in New Guinea

Little is known of the frequency of use and reliance upon tree cavities by wildlife, nor the natural availability of cavities in New Guinea forests. We surveyed the literature for records of cavity use by birds and mammals in New Guinea. We examined every standing tree on one hectare of primary forest and one hectare of secondary forest for cavities, then carefully assessed every tree for cavities after they were felled. We put up 190 artificial nest boxes of five designs in three sites and monitored occupancy. At least 50 species (23.6%) of New Guinea terrestrial mammals and 118 species (17.7%) of non-marine or aquatic bird species are recorded in the literature as using tree cavities. Ground observation identified 36 suspected cavities in a hectare of lowland primary forest and 10 in nearby secondary forest. Upon inspection of all trees after felling, these figures changed to 26 and 0 respectively. Ground censuses are not accurate. Cavities were more commonly found in large trees. In less than a year, nest box occupancy reached exceeded 33%, with Phalanger spp. and Sugar gliders, Petaurus breviceps, being most common. Some bird use was detected by the presence of feathers; snakes and geckos were also found in boxes. Occupancy increased with time and would probably be higher after a second year. The larger boxes had greater occupancy, as did boxes placed higher in the trees. Bees occupied and probably excluded other users from 10% of boxes. As Papuan forests are disturbed by logging, hunting practices and gardening, conservationists might need to manage practices to ensure cavity availability. Artificial nest boxes might have utility for wildlife conservation and research.