The status of microbats on Norfolk Island, southwest Pacific

No evidence for the continued existence of bats was determined during two surveys of Norfolk Island. A pilot survey for bats was undertaken on Norfolk Island in 1986 using harp trap and mist net capture techniques. A subsequent survey in 2003 was undertaken using echolocation call detection equipment. Accounts by island residents indicate that bats were present in reasonable numbers following the 2nd World War but numbers declined dramatically from the early 1960s. Eight former bat roosts were described by island residents. Five of the roosts occurred in hollow-bearing Norfolk Island Pines Araucaria heterophylla, two in houses and one in a large vine. Sightings of bats within the last decade suggest that bats may still persist in low numbers and further survey is warranted. Predation by rats and a gradual decrease in the number of secure roosts through tree removal are considered the most likely causes of decline, although the widespread use of herbicides could also be a factor. Provision of artificial roost boxes may assist in providing secure roosts for any remaining individuals persisting.