“Watch and wait” approach for heat-stressed flying fox colony

Genevieve Jacobs 18 January 2019 15

The NCA will take a ‘watch and wait’ approach to monitoring flying fox heat stress in Commonwealth Park. File photo.

Flying fox roosts in Commonwealth Park will be monitored during the continuing heatwave conditions, but the NCA, which is responsible for the Park, will not take specific action to remediate the extreme heat stress being experienced by the colony.

Region Media reported this week that ACT Wildlife’s trained volunteers had resorted to monitoring the native animals, ready to spray them with water if they fell out of their trees. The coast-dwellers are on their annual migration to Canberra in search of fruit but are struggling to cope with low humidity and high temperatures.

The NCA met with ACT Wildlife yesterday in Commonwealth Park to discuss the flying fox colony and a spokesman said both parties agreed that “the best thing to do is to leave the colony alone and not intervene while they are in the trees as this may affect their natural response mechanisms to heat stress. In order to minimise disturbance, we further agreed that we would not spray the colony or the ground with water”.

ACT chief ecologist Murray Evans said that the mortality point for flying foxes begins around 43 degrees although extreme heat stress can happen before that point, especially among pregnant and lactating females.

“Their main heat control mechanism is wing fanning, moving air across the membrane of their wings. The proportion of flying foxes doing wing fanning will indicate how well the colony is coping with the heat. As the stress increases, they’ll also start licking their wrists and panting.”

Mr Evans said bat experts now recommend minimum disturbance to the colonies because a heat-stressed bat that flies away could well suffer a heat stroke and die. Evidence now also suggests that it’s best not to spray the ground with sprinklers because high humidity on the ground reduces the animals’ ability too cool down.

Flying foxes usually don’t need to drink because their fruit diet contains enough moisture. But the local colony’s location next to Lake Burley Griffin means they can fly out over the water and scoop it up. Mr Evans says that stress monitoring guidelines in NSW and Queensland suggest the colony should only be approached by trained and vaccinated volunteers when foxes are on the ground.

“A gentle spray from a backpack of water might help, but the volunteer should then move away and keep monitoring the situation with minimum disturbance. If the animals are not recovering, they need to be taken into care and rehydrated,” Mr Evans said.

The NCA has conceded this approach may mean that some animals will die, saying “It is unfortunate that despite best efforts that a triage approach may be needed. Those animals ACT Wildlife judge not able to be rehabilitated and returned to the wild will be euthanized as quickly and humanely as possible.”

ACT Wildlife will continue to monitor the colony and advise the NCA about ongoing issues, and signs have now been placed in the area to inform the public about the stresses to the colony. No deaths have been reported as yet in the ACT.

The NCA is in the process of developing a Management Plan for the flying fox colony in the Park. They’ve also expressed gratitude to ACT Wildlife for their dedication and support to the welfare and well-being of the wildlife in the ACT and in particular the flying fox colony in the Park.

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15 Responses to “Watch and wait” approach for heat-stressed flying fox colony
Capital Retro Capital Retro 10:13 am 30 Jan 19

The ABC has reported that the recent hot weather has killed one third of the flying fox population in East Gippsland.

All we have to do is wait for some more hot days.

Margot Sirr Margot Sirr 11:10 pm 29 Jan 19

The bats can carry a disease similar to rabies. I hope they leave the area.

    Julie Macklin Julie Macklin 10:09 am 30 Jan 19

    Yes, and they are pooing over people's vegetable gardens, on roofs where the water flows into rain water tanks, as well as eating the food people grow. While there are fruit trees in people's gardens the bats are unlikely to leave, even though this area is not a natural area for them to be in. I do wonder how they are handling the bat infestation in the orchards in Pialligo. I have noticed nets there now, which are expensive. I wonder if there have always been nets, or just since the bats arrived a few years ago.

Julie Macklin Julie Macklin 11:11 am 21 Jan 19

Last night (as all nights in the fruit season) there was the constant flap flap of wings outside of my window. The bats have striped my apricot tree, my peach tree, all my ripe figs, they are starting on my apples and I suspect when my grapes are ripe they will take them too. I was lucky to get a taste of my fruit, and none that were at peak ripeness, because the bats ate them before that. Last night I rushed outside, the bat took off from my apple tree, and I picked what apples were left. None of them ripe yet, because if I waited for ripe apples there would be NONE. They are out of control and not native to this area. They are only here because of fruit trees people have planted. As someone who tries to grow their food, both for economical reasons and to cut down carbon miles for my food, I am close to crying. I am so upset, because no-one will do anything about this feral pest. I could cage in the trees, but that will likely cost thousands of dollars. PLEASE, PLEASE, PLEASE get rid of them.

    Alan Skeates Alan Skeates 1:59 pm 21 Jan 19

    Just as a matter of interest...I wonder how people protect their fruit trees in areas where flying foxes are native. Have they become a pest in the Riverina and the Golbourne Valley as well?

    Julie Macklin Julie Macklin 2:30 pm 21 Jan 19

    Alan Skeates Huge nets I imagine, which are generally plastic, which breaks down (likely to micro plastic) and need to be replaced regularly. An ongoing expense. Many of the areas that the bats are native to might also have native trees that attract the bats and supply some of the food source. Here much less, so hence their dependence here on fruit trees. And making it impossible to harvest fruit. If people started reacting and cutting down their fruit trees in mass protest, or caging the trees in, the bats would likely starve, they are so dependant on this. I am seriously considering caging my trees in.

    Keith Falkiner Keith Falkiner 11:54 pm 25 Jan 19

    In past vastly more sustainable societies than our present one, all fruits were picked and used in a state we now refer to as green. Think of the vast array of recipes for cooking, drying, and pickling fruits and vegetables in all stages of maturity. This is because previous generations used their brain and worked out how to utilise fruits before the other animals got to eat them. Most humans can appreciate that living as a wild animal is very competitive if you want to eat and survive. Living in the wild doesn’t afford other animals the luxury of eating fruit almost ready to drop. Note the comments of numerous people complaining that the fruit gets eaten before it is to their particular liking. We have developed many technics to stop other animals eating the produce before we deem it ready, that is the advantage of being the most intelligent species on this planet. We have the capacity and simple tools to indulge our luxuries, whether we use this capacity is a matter of choice.

    Julie Macklin Julie Macklin 12:43 am 26 Jan 19

    Keith Falkiner I bottle, dry and store food. Not all of it ripe. In previous societies they would have killed the bats. Some VERY immature figs left (about marble size) and the bats are eating them even.

Maya123 Maya123 1:41 pm 19 Jan 19

The bats are only here because of fruit trees people have planted. (You know, plant your own and cut down carbon kms.) They wouldn’t be otherwise. They have eaten almost all of the fruit on my trees. I look up and when the trees have fruit the bats are coming for them. I shoo them, but as soon as I go inside they are back. I see the neighbour’s fruit tree shaking too with bats. Bat poo down the side of my house. Goodness knows how much is washing into the rainwater tank. They were not here in the past because Canberra’ winters are cold, so this are is not a natural area for them. Get rid of them.
I am considering enclosing the fruit trees to stop the bats (and exploding possum population) any access. It will cost a lot of money to do this. I am willing to share, but the bats and possums are not. I would very much like to taste ripe fruit off my trees, but I can’t, as leave it to ripen the bats eat it before it gets there. So now I pick what I can before it’s at its best. So disappointing.

Dorinda Lillington Dorinda Lillington 8:47 am 19 Jan 19

Let nature take its course. The bats have destroyed the beautiful trees in the park so if their numbers drop perhaps that will help the trees recover.

Mick Johnson Mick Johnson 10:44 pm 18 Jan 19

maybe they should not be here if they cannot handle the conditions

    Alan Skeates Alan Skeates 4:27 pm 19 Jan 19

    I agree. It was only a couple of years ago that they were being regarded as pests as they were stripping fruit off trees every evening. They are no more native to the ACT than Mynahs.

    Kelly Matthews Kelly Matthews 9:05 pm 20 Jan 19

    And you shouldn’t be here either. Stop your air cond and let’s see how you handle the heat.

    Mick Johnson Mick Johnson 9:35 pm 20 Jan 19

    Kelly Matthews dont have air con so there

    Keith Falkiner Keith Falkiner 11:52 pm 25 Jan 19

    Hardly natives, still just newcomers if they have only been in the Canberra area a few million years.

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