The bats of south-east Queensland have left some of their largest colonies, opening the door on one of the biggest mysteries in the world of nature.
That means towns and forests on the east coast of Australia are about to suddenly find they are host to anywhere between 15,000 and 500,000 bats feeding on newly flowering eucalypts.
This change is linked to Australia's drying and warming temperature, one of Australia's leading bat researchers says.
Trish Wimberley, director of the Gold Coast-based Australian Bat Clinic, is the bat expert that Australia's bat experts refer to.
After describing massive south-east Queensland bats camps at Kilcoy (one million little red bats), Linville (500,000 little red bats), Lowood (300,000 bats) and Atkinson's Dam (250,000), she told Fairfax Media in late May a major change was under way.
"I'll tell you right now, something is going on," she said.
"Because every camp, bar Lowood, has not got one bat in them.
"They up and moved last week and we have no idea where they have gone."
Canungra had 12,500 to 20,000 grey-headed bats. Esk had 15,000 to 25,000 grey-headed bats. And there are three large colonies among the Gold Coast's 30 bat colonies, with up to 20,000 bats.
"The same thing has happened in Canungra and Logan," she said.
"So where have they gone and why have they gone?"
Somerset Regional Council confirmed the disappearance of the bats.
"Flying foxes, as of this week, are only at Lowood and we estimate numbers are only about 1500 in the colony there."
Brisbane has 25 relatively small colonies of bats.
Their numbers are also slightly down, but Brisbane City Council says that is part of the normal cycle of breeding and feeding.
"During warmer months, it is normal for flying fox numbers to increase across Brisbane," a wildlife spokesman said.
"This is due, in part, to the arrival of the little red flying foxes on their annual migration coinciding with the breeding season that occurs from February through to April.
"Numbers have been declining in recent weeks since the end of the season."
Bats in south-east Queensland – what is going on?
Three things are bringing bats and humans closer.
First, urban growth has steadily replaced bat habitats (among other fauna) – bushland and mangroves – as more homes, services and infrastructure are built.
In one small example, most of the waterways behind the coast between Tweed Heads and north of Southport included wetlands and mangroves and good bat habitat, Trish Wimberley said.
"Now, 90 per cent of the bat habitat on the Gold Coast is no longer there."
Second, the large bat colonies have shrunk and moved closer to their food sources, flowering eucalypts, as bats adapt.
The shift away from the European "ornamental gardens" in everyone's backyards, to gardens with native species, also bring bats closer to us, Ms Wimberley said.
"So here we are 15 to 20 years later and all those native species are at a height to attract bats. And now they are in our backyards. "
And third, Australia's weather has become warmer and drier.
Now bats – which have spent 60 million years adapting to changing environments – are again adapting to the drying and warming climate by shifting eucalypt forests, Ms Wimberley said.
They are the "giant bees" of pollinators, feeding on flowering eucalypts at night, when the main pollen receptors are available, she explained.
Bats are slowly shifting Australia's eucalypt forests
Eucalypts have recently gone into a "peak flowering mode", seen in Bateman's Bay and the Hunter Valley.
"When you have had a drought – a long drought period – the trees think 'Oh my god, I'm going to die and I've got no children'. In comes the peak flowering, the prolific flowering, then in comes the flying foxes, grabbing all the pollen and seeds, and then they disperse it.
"They are actually going to move the species. So as our climate changes,our flying foxes are redistributing our native species to an area where they can survive.
"And that is definitely what we are noticing."
Dispersing bats – does it work?
In recent years the state government has given the local councils the ability to decide for themselves if it make sense to try to move bat colonies as residents complain.
Many communities are tired of homes and cars being covered with bat faeces, of the noise and the smell.
Councils have tried to move them, with mixed success.
On the Gold Coast, residents have used air horns to shift bats and suggested the Gold Coast City Council cull some of the 200,000 bats remaining in the city.
Charter Towers used car horns and helicopters in December 2013 to shift 80,000 bats, but by November 2014, Townsville was complaining their "bat plague" was Charters Towers' bats.
"It is easy to disperse bats," Ms Wimberley said.
"But you don't know where they are going to go.
"They are going to go into someone's backyard and it is going to be someone else's problem."
Latest research on living with bats
That is what happened in south-east Queensland. Somerset Regional Council ended up with huge bat colonies when neighbouring councils dispersed their bats.
Landcare Australia is now helping five south-east Queensland councils do something to help people live with bats. Trish Wimberley is their chief advisor.
Those councils – Somerset, Toowoomba, Scenic Rim, the Gold and Sunshine coasts – identified pieces of land for permanent bat roots.
Residents in these council areas had became tired of the noise, the smell, the impact of their faeces and, basically, of the bats themselves.
In some cases residents were scared of bats.
Three people have died from bat lyssavirus, but it can only be caught if a person is bitten or scratched by a sick bat. Less than one per cent of wild bats have bat lyssavirus.
What has happened recently to bat colonies in SEQ?
Around Esk, Kilcoy and Linville, the Somerset Regional Council is encouraging the bats – mostly little red flying foxes – to shift to new roosts with attractive eucalypts.
Bats had returned to the old Linville bat roost, despite the best efforts of the council to make it unappealing, Mayor Graeme Lehman said.
"Unfortunately, these works did little to deter the bats who have, in recent weeks, returned to the Linville township," he said.
And then, late in May, those colonies emptied. The flowering eucalypts had called.
On the Sunshine Coast, residents have tried themselves to shift bat roosts at Coolum.
Councillor Steve Robinson said those attempts were "reckless".
"It has only made the situation much worse with bats now also roosting in backyards and closer to the local school," Cr Robinson said.
In Brisbane, the council no longer attempts to shift bats.
On recent example is Perrin Park at Toowong, close to large bat colonies on Indooroopilly Island and Toowong.
"Here we have removed vegetation to create buffer areas between the roost and the playground," the wildlife officer said.
"And we monitor the health and natural population variations in the colony to adapt the maintenance of Perrin Park."