Grey-headed flying fox

Appearance

The grey-headed flying fox is the largest bat in Australia. This flying fox has a dark-grey body with a light-grey head and a reddish-brown neck collar of fur. It is unique among bats of the genus "Pteropus" in that fur on the legs extends all the way to the ankle.

Adults have an average wingspan up to 1 m and can weigh up to 1 kg. The head and body length is between 230 and 289 mm, with an average of 253 mm. The forearm length is between 138 and 180 mm, with an average of 161 mm. Weight generally varies between 600 and 1,000 g, with an average of 677 g.

It is tailless, with claws on its first and second digits. Since it does not echolocate, it lacks tragus or leaf ornamentation found in most species of Microchiroptera. It relies on sight to locate its food and thus has relatively large eyes for a bat.

The grey-headed flying fox is long-lived for a mammal of its size. Individuals reportedly survived in captivity for up to 23 years, and a maximum age of up to 15 years seems possible in the wild.

Distribution

The grey-headed flying fox is endemic to the south-eastern forested areas of Australia, principally east of the Great Dividing Range. Its range extends approximately from Bundaberg to Geelong in Victoria, with outlying colonies in Ingham and Finch Hatton in the north, and in Adelaide in the south. In the southern parts of its range it occupies more extreme latitudes than any other "Pteropus" species.

Status

The grey-headed flying fox is now a prominent federal conservation problem in Australia. Early in the last century, the species was considered abundant, with numbers estimated in the many millions. In recent years, though, direct evidence has been accumulating that the species is in serious decline. Current estimates for the species are about 300,000, and the national population may have declined by over 30% between 1989 and 1999 alone.

Habitat

Grey-headed flying foxes live a variety of habitats, including rainforests, woodlands, and swamps. During the day, individuals reside in large roosts consisting of hundreds to tens of thousands of individuals.

Food

Around dusk, grey-headed flying foxes leave the roost and travel up to 50 km a night to feed on pollen, nectar and fruit. The species consumes fruit flowers and pollens of around 187 plant species.

Predators

Grey-headed flying foxes are exposed to several threats, including loss of foraging and roosting habitat, competition with the black flying fox, and mass die-offs caused by extreme temperature events.

Migration

Movements of grey-headed flying foxes are influenced by the availability of food. Their population is very fluid, as they move in response to the irregular blossoming of certain plant species. The grey-headed flying fox is a partial migrant that uses winds to facilitate long-distance movement. It does not migrate in a specific direction, but rather in the direction that will be the most beneficial at the time.