Life Expectancy, Causes of Death and Movements of the Grey-Headed Flying-Fox (Pteropus poliocephalus) Inferred from Banding

Abstract

This study was designed to generate information on demography and movements in large flying-foxes, information that is critical to management planning. Between 1989 and 2002, 2,244 wild grey-headed flying-foxes, Pteropus poliocephalus, were harp-trapped, banded and released at sites across south-eastern Australia; 918 hand-reared orphans were also banded and released at four sites. Retraps of wild animals were few (n = 10) and are not discussed here. Recoveries (n = 86) from the public reporting dead wild flyingfoxes (total 4.27%) and 38 hand-reared orphans (4.13%) are discussed. Recovery data were analysed via standard multiple regression; there was no difference between the sexes of wild P. poliocephalus in age at death or distance travelled, but hand-reared animals, on average, lived less than half as long as their wild counterparts (P < 0.001) and did not travel as far (P < 0.01). The average age of wild P. poliocephalus at death was 7.1 ± 3.9 years (0 ± SD, n = 86); the oldest flying-fox was 18 years of age. Generation length is estimated at 7.4 ± 3.76 years. Major causes of death of 86 wild P. poliocephalus were: hyperthermia (33.7%); electrocution (18.6%); entanglement in fruit-tree netting (5.8%); entanglement in barbed wire (4.7%); unknown (32.6%). 77% of recoveries of wild-banded P. poliocephalus were within 20 km of where they were banded; the longest movement recorded was 978 km. 1,632 wild black flying-foxes, P. alecto were trapped and banded; 27 were retrapped; seven were recovered dead (0.42%); from another 136 banded as hand-reared orphans, three were recovered (2.2%). Of 583 wild little red flying-foxes, P. scapulatus, trapped and banded, none were retrapped; one was recovered (0.2%). Data from P. alecto and P. scapulatus were too few for statistical analysis.