Flying-fox community news December 2021

Article by Theresa Malin, Natural Areas Conservation Officer, Sunshine Coast Council

Flying-fox roost update

Since our last update both grey-headed and black flying-foxes have been continuing to return from their winter sites to maternity roosts across the Sunshine Coast and are well and truly in birthing season – there are baby bats everywhere! Also known as pups, these cuties have been spotted at primarily coastal maternity roosts at Elizabeth Street Drain (Coolum Beach), Alex Forest Conservation Area (Alex Headland), Kuluin Neighbourhood Park (Kuluin), Emerald Woods Park (Mooloolaba), Albany Creek Park (Sippy Downs), Andrea Ahern Park (Battery Hill) and Pecan Park (Maleny).

For the first six weeks of their lives these pups will be highly dependent on their mums, clinging tightly to her belly and feeding on milk from her teat (which are located in her armpit area – all the easier to wrap a protective wing around). During this vulnerable time the pups aren’t capable of flying independently or getting away from danger, meaning that any disturbances could lead to young being abandoned by their mother. Therefore, unless there is an emergency, we generally only undertake low-impact actions around flying-fox roosts during spring and summer.

Baby bats take their ‘first steps’

At around six weeks of age, pups will become more independent and start hanging outside of their mum’s reach. This means that by early-December we should start seeing some pups taking their ‘first steps’ on the branches above. This is the cue for mums to start leaving their pups in a créche together (like a baby-bat kindergarten) while they take turns heading out to forage for food at night, with one or more ‘aunties’ staying behind to care for them.

When mum returns from feeding she recognises her pup from its call and possibly smell, singling out her baby in a population of sometimes thousands! As the young get older we can expect them to get noisier – you’ll often hear a higher ‘trill’ from sections of a roost as the pup calls for its mum. This period of higher vulnerability also means a roost can be more prone to disturbances or become ‘flighty’ as parents are protecting their young. The birthing season is expected to last until January or February, when the young are more independent and capable of moving away from danger.

What happens next?

Pups will continue feeding on mums’ milk while they start to progressively learn to fly in the roost, and at around three months old they’ll start following the adults out each night to learn how to find their own food. At five or six months old (April to March) pups will have weaned off mum’s milk and be entirely independent. This is the cue for adults to begin mating, which can make for a noisy roost – mating can occur throughout the day and night and generally lasts for around four weeks. The period of mating season can be quite impactful for nearby residents as there can be little reprieve.

However, at around Easter grey-headed and black flying-foxes generally start leaving their coastal roosts to follow flowering events and move to their winter sites for the cooler months.

Want to know more about flying-fox pups? Join bat carer Jeannie Campbell from Bat Rescue Inc to learn about how flying-fox pups drink milk, what carers do to get them to pass flight school, and the unique role that flying-foxes play in supporting our ecosystems.

Be prepared – little red season is coming

So far we have seen Sunshine Coast roosts occupied by grey-headed and black flying-foxes, but we’re expecting some more visitors to arrive for the Christmas break. That’s right, typically little red flying-foxes come to the Sunshine Coast in time for the festivities. Currently in northern and central Queensland, little reds follow the flowering season south to our region and arrive en masse for a traditional feast on the blossoms of primarily Angophora, Corymbia, Eucalyptus and Melaleuca species.

Little reds are named after their physical characteristics – they are smaller than their grey and black counterparts (the smallest flying-fox species in Australia), and their fur is red-brown all over. Little reds feed almost entirely on nectar, with fruit making up only 5% of their diet. They also tend to travel in larger numbers, sometimes in the tens of thousands or more.

While the sudden arrival and disruption of little reds flying-foxes may seem overwhelming at the time, there is light at the end of the tunnel. Fortunately, this species’ behavioural patterns are far more predictable than greys and blacks and they only stay on the Sunshine Coast short-term. It is expected that little reds will leave their roosts around Easter time and head back up north to birth and rear their young.

Little reds depart just as quickly as they arrive. For instance, last season a roost in Nambour saw a sudden influx of little reds that rose from 0 to 345,000 within a few weeks in mid-December. However, by mid-January the numbers had dropped by nearly two-thirds and in February they had gone altogether, as shown in the graph below.

The sharp increase in numbers and unique behaviour of little red flying-foxes tend to make for a more disruptive roost. While grey-headed and blacks co-habitat quite peacefully and respect each other’s territory, little reds tend to invade personal space. This inevitably leads to rowdy and noisy turf wars. Kind of like that unruly kid who gets on the red cordial then amps the other kids up at the family Christmas lunch, causing a racket. Add to this the facts that little reds use this time and territory to mate, and their highly mobile nature (a staggering 36.4% of little reds shift sites daily, meaning every night at least one-third of the reds in the roost are new-comers)…. and you have yourself one big shindig.

Council routinely monitors all urban flying-fox roosts across the Sunshine Coast. Monitoring numbers at all council roosts are recorded and publicly viewable on BatMap here. Through this mapping interface you can access all kinds of roost-specific data like current and historical management actions, past and present roost extents, flying-fox numbers and even a break-down of each species within a roost. You may find it interesting to get on to BatMap and find a roost near you to see how flying-fox numbers and species compositions change in your area over the seasons.

Top tips for living with these noisy neighbours

Bring your washing in at night
Park your cars under shelter
Keep doors and windows closed at dawn and dusk to reduce disturbance during fly-in and fly-out
Remove or cover fruit and flowers on fruiting and flowering trees on your property
Keep dogs and cats inside at night and away from roost sites. Keep food and water indoors
Move quietly near roost sites to avoid disturbance – they make more noise when disturbed.

Your planting choices matter

Summer is fast approaching and we’re all busy in our backyards getting a few more plants in before the higher temperatures arrive, but before you reach for your old go-to tropical species, why not check out our planting guidelines? These were developed to assist residents living near seasonal flying-fox roosts on the Sunshine Coast. With just a few changes to your species choice, the impacts of living near a roost can be significantly reduced.

Flying-foxes primarily eat native fruit and especially love nectar and pollen – it’s their favourite food! Many of our favourite backyard species produce high amounts of nectar and pollen. This can be great if you want to attract lorikeets and honey eaters but be mindful that they aren’t the only animals that like these species.

This can also potentially present a problem when the bats come home to roost. Flying is a very energy-expensive exercise, so to conserve energy flying-foxes generally roost nearby good foraging habitat. This is why their numbers fluctuate and they constantly move to different roosts, to be nearby fruit and flowering trees. By planting their preferred feed trees in your garden, you could be encouraging flying-foxes to roost nearby. If this is something you want to avoid, check out the following guidelines on how best to plant for the coming seasons.

To discourage foraging

Plant trees that:

produce discreet or low nectar-producing flowers
are in flower for brief periods
do not produce soft fruit.

Avoid planting trees with:

large, solitary flowers or flower inflorescences (clusters of flowers)—particularly light-coloured varieties that are easily seen at night
soft fruits or berries
stone fruits such as mangoes
figs
known foraging trees including eucalypts, cocos palms, grevilleas and lillypillies.

To discourage roosting

Flying-foxes are social animals that typically roost in clumps of tall, closely positioned trees where there is a dense understorey of vegetation. Therefore:

avoid planting trees in clusters or clumps
in some circumstances, clearing of understorey garden plants and minor trimming of tree branches may make roost trees on private land less attractive to flying-foxes
plant trees or shrubs that grow, or can be pruned to less than three metres
Flying-foxes roost in all types of trees. When shading is required, plant trees such as kurrajong that have low nectar-producing flowers.