The Spectacled Flying Fox

Skyrail Nature Diary: September 2011

Photo - Adam McKeown, CSIRO

If you look to the skies after dusk at this time of year you are quite likely to see flocks of the distinctive Spectacled Flying-fox (Pteropus conspicillatus), heading out for a night of feeding and socialising.

Like most mammals in Australia's Tropical Rainforests, the Spectacled Flying-fox is nocturnal. It uses its highly-developed sense of smell, eyesight and colour recognition to find its favourite foods, which include eucalypts, figs, lilly pillys and grevilleas.

The common name comes from the distinctive colouring of the Spectacled Flying Fox. Patches of pale yellow fur surround the Flying-fox’s eyes, contrasting strongly with the animal’s otherwise dark body colouring, which gives the appearance of the animal wearing glasses.

The Spectacled Flying-fox plays a critical role in the pollen and seed dispersal, and subsequent regeneration, of at least 26 rainforest tree species. In fact, the Spectacled Flying-fox will often travel up to 100km each night when searching for food.

Also known as the Spectacled Fruit Bat, this Flying-fox is frugivorous (it only eats fruit), feeding primarily upon the fruit, flowers and nectar of native rainforest plants. It roosts in large trees close to rainforest, with up to 10,000 individuals congregating at a time during breeding season; a little noisy if you live next door!

Breeding season, from September to November, is an important time of year for this species, with the Spectacled Flying-foxes only giving birth to one offspring each year. Young bats cling to their mother's underside until about one month old, when they become too heavy to carry and are left in the roosting tree. They reach adult size, approximately 25cm in length and weighing 0.5kg, at around two years of age. Not much is known about their natural life expectancy however, one captive individual reached the grand age of 17.

A member of the Pteropididae (Flying-fox) family, the Spectacled Flying-fox joins the Little Red Flying-fox, Black Flying-fox and Grey-headed Flying-fox as one of four native Flying-fox species found in Queensland. Of these four species, the Spectacled Flying-fox has the smallest distribution in Australia; their natural range is limited to Australia’s World Heritage listed Tropical Rainforests, as well as Papua New Guinea and its surrounding islands.

Threats to Spectacled Flying-fox populations include powerlines, paralysis ticks and (believe it or not) crocodiles: Flying-foxes skim low over water sources to drink, presenting a tasty snack for any lucky crocodiles lurking beneath the surface.

However, land clearing has also proved a major threat, causing significant loss of habitat and resulting in a decline in Spectacled Flying-fox populations. It was listed as ‘Vulnerable’ on the Commonwealth Environment Protection and Biodiversity Conservation Act in 2002.