Grey-headed Flying Fox

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Akuli 21:19, 21 November 2006 (UTC)

iGrey-headed flying fox

Conservation status

Least concern (LR/lc)

Scientific classification

Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Chiroptera
Family:	Pteropodidae
Genus:	Pteropus
Species:	P. poliocephalus

Binomial name

Pteropus poliocephalus
(Temminck, 1825)

The 'grey-headed flying fox' (Pteropus poliocephalus) is a fruitbat native to Australia. Grey-headed flying foxes have a maximum wingspan of over 1 meter and can weigh up to 1 kg. They are distinguished from other flying fox species by the grey or white fur on their head and leg fur that extends to the ankles. During the day individuals reside in large roosts consisting of hundreds to tens of thousands of individuals. At night, the bats travel up to 50 km to feed on blossom, nectar and fruit. Breeding occurs in March and April. Pregnant females give birth to a single pup in September or October. The grey-headed flying fox is long-lived and there are reports of individuals surviving in captivity for up to 23 years, and a maximum age of up to 15 years seems possible in the wild.

The species is endemic to the south-eastern forested areas of Australia, principally east of the Great Dividing Range. It extends from Bundaberg in southern Queensland to Geelong, Victoria, where it occupies a more extreme latitude than any other megachiropteran species.

Grey-headed flying foxes, along with the three other Australian flying fox species, fulfill a very important ecological role by dispersing the seeds and pollen of native plants. The food sources usually associated with the grey-headed flying fox belong mainly to the genera Eucalyptus, Angophora, Melaleuca and Banksia, but in some areas it also utilises a wide range of rainforest fruit. The grey-headed flying fox is the only mammalian frugivore to occupy substantial areas of subtropical rainforests and so is of key importance for seed dispersal in those forests. Most vegetation communities used by the grey-headed flying fox produce foraging resources in seasonal but annually irregular superabundant pulses, and the grey-headed flying fox has adopted complex migration traits in response to such ephemeral and patchy food resources. However, there are some temporally and spatially reliable resources restricted to a small number of coastal vegetation communities in northern New South Wales and Queensland that may support smaller resident populations.

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

Grey-headed flying foxes are exposed to several threatening processes, including loss of foraging and roosting habitat, competition with the black flying fox (P. alecto), and mass die-offs caused by hyperthermia during extreme climatic events. When present in urban environments grey-headed flying foxes are sometimes perceived as a nuisance. Cultivated orchard fruits are also taken but apparently only at times when other food items are scarce. Because the roosting and foraging habits of the grey-headed flying fox bring the species into conflict with humans, the species suffers from direct killing of animals in orchards and harassment and destruction of roosts. Negative public perception of the species has intensified with the discovery of three recently emerged zoonotic viruses that are potentially fatal to humans: Hendra virus, Australian bat lyssavirus and Menangle virus. However, only Australian bat lyssavirus is known from two isolated cases to be directly transmissible from bats to humans.

To answer some of these growing threats, roost sites have been legally protected since 1986 in New South Wales and since 1994 in Queensland. In 1999 the species was classified as ‘vulnerable to extinction’ in the Action Plan for Australian Bats, and the species is now protected by law across its range.

Often flying foxes come to the attention of WIRES, the Australian wildlife care and rescue organization, when reported as injured etc. A very high proportion of flying fox injuries are caused by fruit tree netting or barbed wire fences, both of which can can result in a slow and agonizing death for the animal if not rescued. Young flying foxes also come into the care of WIRES bat carers, who are specially trained to raise and rehabilitate. Although the chance of contracting Australian bat lyssavirus is extremely small bat carers are inoculated for their own protection.

A baby flying fox usually comes into care after being separated from its mother; reasons for separation can be wide and varied including the death of the mother. Most babies are in a dehydrated and distressed state by the time they are rescued and some are infested with maggots if injured. A young flying fox must be fed every 4 hours up to 6 times a day, and then as it grows it is introduced to blossoms and fruit. At around 10 to 12 weeks of age, when fully weaned the baby bat goes to crèche for rehabilitation and eventual release.

Illustration	Grey-headed flying foxs in the Royal Botanic Gardens, Sydney	Maximum wingspan of over 1 metre	17 day old Grey-headed flying fox (female) in care of WIRES
Young Grey-headed flying fox (female) graduating to "the playpen"	Young Grey-headed flying fox (female) in care of WIRES	Young Grey-headed flying fox playing with "Mum" her WIRES bat carer