Grey-Headed Flying Fox, Pteropus poliocephalus

The grey-headed flying fox (Pteropus poliocephalus) is a species of megabat that can be found in Australia. Its range includes a large area east of the Great Dividing Range that extends from Geelong to Bundaberg and includes Finch Hatton, Ingham, and Adelaide. It prefers a habitat within many areas including swamps, rainforests, and woodlands.

The grey-headed flying fox is the largest bat within its range, reaching an average body length between 9.1 and 11.4 inches, a wingspan of up to 3.3 feet, and a weight of up to 2.2 pounds. Its fur is dark grey along its body, light grey along its head, and reddish- brown along its neck. This species can be distinguished from other bats by it leg fur, which extends to the ankles.

Like other species of bat, the grey-headed flying fox is nocturnal and spends the day roosting in vegetation in natural areas and in areas where humans are present. Colonies of this species are notably large, reaching between hundreds and tens of thousands of individuals. The species is migratory holding summer and winter roosts, both with varying territories. Summer roosts are used between the months of September to April or June, when males will form breeding territories. Winter roosts are thought of as transition roosts and are used during the rest of the year, when the bats will form same-sex groups.

The typically breeding season of the grey-headed flying fox occurs between the months of March and May, but it is thought that conception occurs in April. Males will form mating territories and mark them with glands found on the neck. They will fight to hold central territories, or harems, where up to five females reside for a varied amount of time. Males found in periphery territories are often single or polygamous. Females control the mating process, which typically occurs during the daytime hours. After a pregnancy period of twenty-seven weeks, females give birth to one pup between the months of September to November. The pups cling to their mother for the first three weeks after birth and remain in the roost until January, when they are able to fly. Weaning occurs between the months of February to April.

The grey-headed flying fox leaves its roost at dusk and will fly as far as thirty-one miles to find food. This behavior is not related to seasonal migrations, but depends upon food abundance, making it highly irregular. The species consumes the fruit, pollen, and nectar of over 187 plant species including Eucalyptus and Ficus plants. Because it feeds on so many plant species, it is considered an important seed disperser. Its feeding habits are also dependent upon proper light levels and the risk of predation, which can come from a number of animals including snakes, crocodiles, and eagles.

The grey-headed flying fox has many threats including habitat loss, which affects foraging and roosting, competition with the black-flying fox, and die-offs caused by extreme weather events. In areas of its range that hold humans, it can be considered a threat and is sometimes killed by fruit farmers. A negative perception of this bat has increased since the discovery of three new zoonotic viruses, which could potentially harm humans, but only the Australian bat lyssavirus is known to be transmittable to humans. This species was once abundant, thought to number in the millions, but recent estimations have been recorded at only 300,000 bats, with a possible decline of thirty percent between 1989 and 1999.

There are many groups dedicated to helping bat species including WIRES and Wildlife Victoria, among many others, which help injured, sick, or orphaned bats. Baby bats are typically orphaned when they fall off their mothers while flying in search of food, but they can be abandoned in large numbers for unknown reasons. Most adult bats are injured when flying into a power line, which occurs at a surprisingly high rate. All bat caregivers are inoculated with the rabies vaccine, although the chances of contracting the disease or any others from bats are relatively low.

There have been many conservation efforts developed to help save the grey-headed flying fox. These include legal protection of roosts that was given to the bats in 1986 in New South Wales and in 1994 in Queensland. Federal Australian law first protected the bat in 1999, when it was listed in The Action Plan for Australian Bats as “vulnerable to extinction.†The grey-headed flying fox currently appears on the IUCN Red List with a conservation status of “Vulnerable.â€

Image Caption: Roosting Grey-headed flying-foxes. Credit: Justin Welbergen/Wikipedia (CC BY 3.0)