Article and images by Tyron de Kauwe, Natural Areas Conservation Officer, Sunshine Coast Council
Like caravaners from the colder states, our seasonal visitors—the little red flying-fox—decided to spend the summer in Southeast Queensland. Their annual migration from Northern and Western Queensland started in the middle of December, and they returned home just as swiftly as they arrived, heading back north by Easter.
This season saw unheralded numbers of little reds visit this area, likely due to drought conditions in their primary sites and heavy flowering of summer species such as bloodwoods in Southeast Queensland. February saw the peak of numbers, with over 35,000 across all of the Sunshine Coast roosts and over 50,000 in Noosa.
As it stands, almost all of the monitored sites have been vacated, with flying-foxes moving to their winter roosts further north.
"Pop-up" camps and the "flying-fox effect"
Potentially due to adverse climatic conditions across Queensland in the recent months, we have observed a shift in the occupation of the monitored urban roosts and also the emergence of several "pop-up" camps in areas that have not been occupied in the past.
These are small, satellite camps that occur in small patches of vegetation where flying-foxes stay for a few weeks or less before moving on.
Many experts link this phenomenon to the drought, fire and flood trifecta which hit Queensland in late 2018 and early 2019, leading to local flying-foxes having less available food and therefore not sufficient energy to make the trek from their summer sites to their winter sites in one go. In many sites, there has also been a shift in their location to ensure they are closer to food sources.
Grey-headed flying-foxes are considered to exist as one national population, spanning from Hervey Bay to Melbourne and even across to Adelaide, with a turnover of around 10% of flying-foxes moving between camps every day. Therefore, changes in conditions at other sites across their range can impact the way historic sites are used and may result in changes from the "normal" occupation cycles.
Pop-up camps have been observed across the country over summer and autumn, illustrating how complex and interconnected flying-fox ecology is. These also demonstrate how even management actions of other councils could influence the "normal" cycle locally — perhaps the “butterfly effect” should be renamed the “flying-fox effect!”
The positive outcome from the emergence of these pop-up camps is the increase in reporting from residents. Many people have contacted council to report the emergence of camps, which enables more accurate monitoring and a better understanding of where flying-foxes are moving.
The curious case of Elizabeth Street Drain
Since the poisoning of over 50 mature roost trees by a community member occurred at Elizabeth St Drain in Coolum around 18 months ago, there have been many changes across the roost.
It was expected that flying-foxes would not reinhabit the site as their primary roost trees had been killed. Surprisingly, pregnant flying-foxes returned to this site last summer to give birth and it even had little reds in the area closest to the drainage channel—with flying-foxes and other wildlife still using the dead trees.
Upon witnessing a fly-out at the site over summer, it was observed that the males flying out next to the new mums were noticeably smaller in size. Male flying-foxes become sexually mature around 30 months of age; females around two years, leading to adult males typically being almost 5% larger in size and 25-40% heavier than adult females.
The noticeable size difference seen at this Coolum site may indicate that the males roosting there are sub-adult and may have been born there the season before and returned to what they remembered as a suitable site. Similarly, many of the females may well have been born there two years before and when it came time for them to give birth, they simply returned to a known maternity site.
While it is impossible to ever guarantee the movements of wild animals, perhaps those that used the site this year communicated with other adults and determined there are better roost sites to raise their young this season.
Despite the substantial degradation of this site, it still houses many native animals. It is intended that this park continue to be rehabilitated to a point where wildlife can safely reside.
While the flying-foxes have seasonally vacated the site, there is an opportunity for weed management to be performed throughout the site without concern of disturbing the roost. A concerted effort will be made over winter to cover a larger area of this site to allow natural regeneration while the flying foxes have vacated. Replanting of species killed will also take place in the near future to help regenerate this site.
For another year, Geckoes Wildlife held exciting and educational presentations across six libraries in March and April. The series was so popular an extra venue was added this year to allow more people to attend. As always, Martin Fingland was incredibly entertaining and he informed over 300 people of all ages about all the nocturnal visitors to their backyards.
Further struggles for the spectacled flying-fox
After the horrific heatwave in Cairns knocked out around 30% of the national spectacled flying-fox population in November, the species was federally listed as Endangered. According to the latest figures from the North Queensland Conservation Council, the Australian population of this species has crashed from approx. 250,000 in 2004 to around 40,000 at the end of 2018. This dramatic drop in numbers would meet the criteria to be listed as Critically Endangered.
Another batty celebration at Mary Cairncross Scenic Reserve
The Australasian Bat Night has grown from humble beginnings into the biggest event on the flying-fox calendar. The event celebrated its fifth birthday this April, with over 150 people enjoying the stalls and activities and learning all about the important role bats play in the environment. Attendees were able to hang upside down like a bat with the experts from Absolute Aerial, Coolum; make bat mobiles from recycled green waste; screen print a free "bat pack" calico bag; visit informative stalls from council and carers; and hear from a range of expert speakers. The highlight of the night was Clancy Hall carrying the torch for her father Les and delivering an engaging and informative presentation filled with "bat facts".
Technology meets nature to awaken our senses
Council is holding the Doonan Open Data Expo on Friday 21 June, from 8am - 2pm, to help ignite the passion of citizens as future-makers for biodiversity. At the free event, council will showcase how data and technology is used in environmental monitoring and creating awareness of nature.
There will be many stalls with guest exhibitors, including the “bat cave”where attendees can experience augmented reality bat flight.
Keynote speakers at this event include:
- Stefan Sawynok, InfoFish Australia - Monitoring waterways using citizen science and data implants in fish.
- Andrew Skeoch, Listening Earth - Open your ears to the World's wild environments.
- Nat Parker, Airborn Insight - Environmental management with drones.
- Professor Stuart Parsons, QUT - How is technology transforming how we study bats? From citizen science to artificial intelligence.
- Kate Hofmeister, Sunshine Coast Council - Turtle satellite tracking
Be part of the immersive encounters with creatures and forests, where answers are revealed! To learn more and book for the event visit our website.
Bats in Focus
This month, we focus on Australia’s only carnivorous flying-fox. The Ghost bat ( Macroderma gigas) is the country’s largest microbat and second largest in the world. They can be found roosting in caves, old mine shafts, deep cracks in rocks and sometimes even abandoned buildings.
Ghost bats use both their strong eyesight and echolocation to find their prey, which includes large insects, frogs, birds, lizards and small mammals …sometimes even other bats! After swooping in and biting their prey, they then take it back to the safety of their cave to eat.
In an unusual feature for microbats, this species’ ears join over their head with a thin membrane of skin. And despite having no tail, there is a tail membrane that connects their hind legs.
This fascinating creature used to span most of inland Australia. However, now it is restricted to tropical northern Australia. The Ghost bat is listed as "vulnerable" to extinction federally and "endangered" in Queensland. The main reasons for their threatened status is thought to be from destruction of caves by mining, entanglement in barbed wire fences and loss of feeding habitat by clearing and land degradation from agriculture.