ROOST SELECTION BY THE NORTH QUEENSLAND LONG-EARED BAT NYCTOPHILUS-BIFAX IN LITTORAL RAIN-FOREST IN THE ILUKA WORLD HERITAGE AREA, NEW-SOUTH-WALES

The aim of this study was to describe the roosts of Nyctophilus bifax in littoral rainforest in Iluka Nature Reserve on the north coast of N ew South Wales. Radio-telemetry was used to track 17 bats in November 1988 (lactation season) and 11 in May 1989 (mating season) to 87 roost s in 49 trees within the littoral rainforest. The bats frequently chan ged roosts, which were clustered within a small area. During November, lactating females moved twins between diurnal roosts and some carried twins while foraging. Twins represented a load of up to 95% of their mother's bodyweight. Bats roosted communally in foliage and tree hollo ws, beneath peeling bark, among epiphytes, and between strangler figs and host trees. Hollows were used more frequently when bats were lacta ting, while the use of foliage roosts was greater during the mating se ason. Roosts were concentrated in four tree species, although a wide r ange of other tree species was used. Roost trees used in November were taller (17 m) than those used in May (8.2 m), and reflect selection o f Syzygium leuhmannii and A cmena hemilampra, both trees of the forest interior. The converse applied for selection of Cupaniopsis anacardio ides, a small tree of the littoral zone, in May. These results identif y the need for conserving a diversity of roosts for this species of ba t.