Grey-headed flying foxes (Pteropus poliocephalus) are unique to Australia and are the largest Australian bat species. They can be found in central Queensland, New South Wales, Victoria and South Australia.
About flying foxes
Flying foxes are a threatened species and are considered vulnerable to extinction locally and nationally. In South Australia they are protected under the National Parks and Wildlife Act 1972
They usually form a single population in each state and can spread out to smaller camps to feed. They have a wingspan up to one metre, and weigh up to one kilogram each.
Arrival and establishment in Adelaide
Grey-headed flying foxes have been visiting South Australia for many decades, but only in 2010 did they set up a permanent camp at Botanic Park in the city.
This is thought to be because drought conditions, habitat loss and the effects of climate change forced the bats to travel interstate from NSW and Victoria to Adelaide for space and food.
Adelaide’s grey-headed flying fox population sits at around 20,000, with a peak of 33,000 in early 2022. Hot summers in Adelaide usually result in a high number of young flying fox deaths, as they struggle to live with the heat.
Grey-headed flying fox population growth in Adelaide since arrival in 2010
Adelaide’s reliable habitat and easy access to water and food like blossoms and fruit crops has supported the population setting up in South Australia.
Another 4,000 flying foxes have recently made themselves at home in a pine forest near Millicent in the regional south-east of South Australia. It’s likely that other camps will be established in the greater Adelaide and Mount Lofty Ranges area. New camps are likely to be smaller in size and more seasonal.
Diet
They find food using their strong sense of smell and excellent vision. They love to eat blossoms from eucalypt, banksia and gum trees, and will also happily settle for fruit like apples, pears, cherries, dates and figs.
2 bats in Botanic Park in Adelaide City. Credit: City of Adelaide
Behaviour
Grey-headed flying foxes hang upside down in trees to roost during the day, usually with their wings folded or wrapped around their bodies.
They are vocal, clean, intelligent and social animals. They gather in large numbers known as 'camps' to protect themselves from predators like eagles and owls.
Flying foxes are nocturnal, so they forage for food at night usually within 20 kilometres of their camp. They leave the camp at around dusk each evening and return before dawn.
Breeding
Fruit bats mate throughout the year, but conception typically occurs between March and May when the males become fertile.
Once the female is pregnant, gestation lasts 6 months and females give birth to a pup between September and November. The pup clings to its mother’s belly and is carried by her for 3 to 5 weeks before being left in a crèche area of the camp at night.
Pups are weaned at around 5 months, and after some practice, fly out with the adults at night to feed on flowers and fruits.
Young flying foxes are prone to misadventure and mortality rates are high during the first 2 years.
Threats to survival
Grey-headed flying foxes are at risk of extinction due to:
- loss of natural feeding habitats and camp sites
- slow reproductive rate (one young per year) and high juvenile mortality rate
- increases in urbanised populations which leads to greater conflicts with humans
- legal and illegal destruction of flying foxes eating orchards (primarily in the eastern states)
- effects of climate change, including extreme heat events and decreased productivity in their food resources.
A flying fox cooling down in the River Torrens in Adelaide city. Credit: Craig Greer
3 fruit bat takeaways
- If you find an injured or dead flying fox contact a wildlife rescue organisation such as Fauna Rescue or Bat Rescue SA to help.
- On hot days flying foxes drink from the River Torrens. Don't worry if you see one in the river, they can swim!
- All bat species, including the grey-headed flying fox, are potential carriers of disease - its rare, but possible. So remember to not touch them. For more health information visit the SA Health website.
