Roosting and foraging ecology of the Queensland blossom bat (Syconycteris australis) in north-eastern New South Wales: flexibility in response to seasonal variation

Abstract

Radiotelemetry was used to track blossom bats (Syconycteris australis) at Iluka and Harrington in northern New South Wales. A total of 31 bats was tracked to 110 roosts. Bats foraged on nectar and pollen in Banksia integrtfolia heathland, but roosted 50-4000m away in littoral rainforest. Bats showed a strong fidelity to their feeding area (about 13ha), returning to their original capture point each night and spending a large proportion of their foraging time there. After leaving their roost, adults spent, on average, 45% of their time active and remained in heathland throughout the night. All age-sex classes roosted solitarily during the day amongst rainforest foliage, usually in the subcanopy layer. Most roosts were occupied for one day only and adults were more roost-mobile than juveniles. Mean movements between roosts were greater at Harrington (125m), where the rainforest is fragmented, than at Iluka (42m), where rainforest is intact. Bats shifted their roosts seasonally, from the rainforest edge in winter to the rainforest interior in spring/autumn. This behaviour allows for avoidance of cold temperatures inside the forest in winter and of hot temperatures of the forest exterior in spring/autumn. A further possible response to the seasonal climate prevailing at the study area was a reduction in the commuting distance (from roosts to feeding areas) from autumn/spring (1.4km) to winter (0.8km). Such flexible roosting and foraging strategies may be effective in allowing S. australis to exploit subtropical and temperate areas of Australia.