The Grey-headed Flying-foxes (GHFFs) first set up camp in the Wolli valley in mid-2007, and then numbered a few hundred. There are no historical records of their previous presence in the valley, although it is possible that they have roosted in the valley in earlier times.
During the day, the Flying-foxes roost by hanging in the canopy of the Eucalyptus and Casuarina trees that can be found in the main camp area which lies between the railway line and Wolli creek at Turrella. These trees were planted in the early 1980’s as part of a revegetation project. As the camp has expanded, many flying foxes have moved cross the creek to roost in other tree species as well.
The GHFF camp is next to the creek, and on hot evenings the Flying-foxes can be seen belly-dipping into the creek before going out to feed for the night. They do this in order to drink, and to cool off. After belly-dipping into the water (which takes skill to master) they can be seen licking the water off their fur, after landing in nearby trees. Click on the YouTube link to see a great video of this activity.http://www.youtube.com/watch?v=d_j5aDaykGk
The Wolli Valley camp was initially a seasonal camp – with the Flying-foxes leaving the camp during the cooler months and in response to available food sources. Since winter 2013 onwards, the camp has been continuously occupied, suggesting it has moved from being a seasonal camp to a permanent one. Numbers present (in the thousands) fluctuate. In November 2016 around 24,000 Flying-foxes were counted, which is the highest number yet recorded.
Fly-out counting by WCPS volunteers commenced in April 2008 as part of regular synchronised counts then occurring up and down their range along the east coast of Australia. These synchronised counts contributed to research work about the population dynamics and movements of this now vulnerable mammal species (see Billie Roberts Griffith University ). WCPS continues to monitor the presence and numbers of GHFF by conducting regular fly-out (exit) counts. See “bat counting” page if you are interested in being involved.
The Royal Botanic Gardens conducted a controversial ‘relocation’ action in 2012/2013 to displace the colony of Grey-headed Flying-foxes that had roosted there for many years. The Society submitted its objections to this action via the public consultation process required under Commonwealth legislation Download the Society’s submission here.
WCPS has an annual ‘Bat Watch Picnic’ event in Turrella Reserve, usually organised in March in conjunction with Australasian Bat Night http://ausbats.org.au/australasian-bat-night/4581984807 This is an early evening, BYO picnic event, where families and friends are encouraged to come down to Turrella Reserve to enjoy the sight of the daily fly-out of thousands of Flying-foxes as they exit the Wolli/Turrella camp in search of food. Batty craft is also available for young and old to enjoy. Watch videos of this event from March 2015 https://www.youtube.com/watch?v=FipoHteOzMEa and 2016 https://youtu.be/KefhGW8kxvQ and see some photos from the 2017 event here https://www.flickr.com/photos/wolli_events/albums
The Society has also given talks to classes from local schools who have come down to the Wolli Valley to view the camp and hear about the GHFF’s there. In 2016 students from a year 2 class at Athelstane Public School in Arncliffe, who had been given a talk, won the Society’s Rankin Environment Award for their artwork based on their visit to the Valley and their experience of its natural environment (including the GHFF). Here is a link to their lovely video https://www.youtube.com/watch?v=vNJYAPr_Ltc
Some Grey-headed Flying-fox facts
- The scientific name of the Grey-headed Flying-fox is Pteropus poliocephalus
- They are warm-blooded, nomadic, social mammals.
- They have a wing span of roughly a metre, and weigh up to a kilogram
- They are often called fruit bats, but they feed mainly on the blossoms (nectar and pollen) of Eucalyptus, Melaleuca, Turpentine and Banksia trees, as well as rainforest fruits (eg Figs, Lilly Pillys). They will feed on cultivated fruit when there is a shortage of their native food.
- They feed at night and generally travel within a radius of up to 30 km from their camp, visiting a number of trees along the way.
- They play an important role in maintaining forests along the east coast of Australia, as they pollinate blossoms and spread seeds during their long distance travels in search of food.
- Only one baby is born each year, usually in October. In urban areas at this time, and for the next few months, female GHFF are particularly in danger of coming into contact with and dying on electric power lines as they carry the (increasing) weight of their young pups while out feeding. Their pups however can often survive this tragedy. For information on what to do if you see a GHFF hanging from power lines download the info sheet (PDF) ‘Flying Foxes on Power lines’ .
- They are in great danger of dying when temperatures reach 40 + degrees C, particularly the pups. Many fatalities occur in camps due to heat stress and dehydration. See a video of a rescue of pups which took place in the Wolli Valley when the temperature in Sydney reached 46 degrees C on 18/1/2013.
- They have many different calls. These calls become louder in the mating season, (March to May) when the males ‘shout’ in the face of females as part of their breeding ritual, and there are squabbles over territory. They also can be heard while out and about feeding in trees at night, as they defend their feeding territory.
- Despite the numbers now seen in urban areas around Sydney, overall GHFF numbers have dramatically declined. In 2001 The Commonwealth, NSW and Victorian governments listed the GHFF as a threatened species. It has been classified as ‘vulnerable’.
- It’s estimated that the area of habitat available for GHFF’s has been reduced by 50% since European occupation. Human activities such as land clearing for agriculture and urban expansion have lead to this reduction.
If you encounter an injured Grey-headed Flying-fox, unless you have been vaccinated against the diseases they sometimes carry, do not handle the animal but contact WIRES on 8977 3333 or Sydney Wildlife on 9413 4300. Many Flying-foxes become entangled in netting placed over fruit trees. Do not try to disentangle the Flying-fox yourself, but call the WIRES or Sydney Wildlife numbers listed. You can prevent injury to Flying-foxes and protect your fruit by installing wildlife friendly netting. A brochure can be downloaded here Wildlife friendly netting And here are some videos of rescued young GHFF in the care of dedicated and vaccinated wildlife carers https://www.youtube.com/watch?v=GdP44iBIvck, https://www.youtube.com/watch?v=BErUdRMSd-U and this amazing video https://www.youtube.com/watch?v=0z1NB4Cy8bw
For further background information on GHFF download article prepared by Andrew Smith (2007).
and for a ‘rap version’ of these GHFF facts ( a Bat Rap by Peter Noble) see https://www.youtube.com/watch?v=hoFNBAhEquc#t=85
For an engaging TEDx talk on GHFF in 2013, by wildlife ecologist Tim Pearson, see https://www.youtube.com/watch?v=qnOhS5jVBFk
Useful Links for more information:
www.sydneybats.org.au – Flying-foxes in Sydney. Contains lots of useful information and links to other relevant websites
www.abs.ausbats.org.au – Australasian Bat Society
www.environment.nsw.gov.au – The website of the NSW Office of Environment and Heritage
www.bellingen.com/flyingfoxes/ – Information about the Bellingen camp in northern NSW. Some superb photographs can be found on this site.
http://australianmuseum.net.au/Australian-bats – Information from The Australian Museum website.
Wildlife Habitats – For information about native plants of the Wolli valley that can provide food for GHFF’s see our Wildlife Habitat Plants page