A new estimate of the population size of the Critically Endangered Rodrigues fruit bat Pteropus rodricensis

Abstract

The Rodrigues fruit bat Pteropus rodricensis is endemic to Rodrigues Island, the smallest of the Mascarene Islands in the Indian Ocean. The species is categorized as Critically Endangered on the IUCN Red List. A study between February 2001 and February 2002 identified 10 roosts, four previously unrecorded. Roost sites were located in the north and south of the island, all within forested valleys. Sixteen counts of each roost site, evenly spaced throughout the study period, showed dramatic changes in individual colony numbers, suggesting movement between roosts. Simultaneous counts of all colonies resulted in a minimum population estimate of 5,076, which is substantially higher than previous estimates of the species. This is believed to be due to a population increase since the last count, newly identified roosts and the movement of bats into different areas, allowing more accurate counts to be made.