Thousands of threatened flying foxes have dropped dead due to heat stress brought on by extreme temperatures in far north Queensland this week.

Conservationists and wildlife volunteers estimate more than 4,000 have perished this week during the record heatwave, which has seen temperatures in Cairns reach all-time highs of 42.6C.

The species of flying fox affected is the spectacled flying fox, an endemic Queensland species found in north Queensland.

It’s currently listed as vulnerable under national environment laws but conservationists have been pushing to have the species up-listed to endangered because of declines in the population.

Volunteer carers that have been counting dead animals and taking orphaned young into care say it is the first time the species has suffered mass deaths because of extreme heat.

“It’s never had a heat stress event before because it’s in the tropics,” said Maree Treadwell Kerr, a wildlife carer and president of the Bats and Tree Society of Cairns.

Treadwell Kerr said the species was already struggling before this week’s extreme heat as a result of a dry winter, which had affected the bat’s food sources.

At the end of October, 331 animals had already been found dead or orphaned in the Cairns region.

She said carers were already concerned about drops in population numbers in recent years and the extreme weather would now put more pressure on the species.

“It’s an estimate, but we’ve probably lost more than 10% in the past week,” she said.

Volunteers found 3,000 dead bats and 54 live bats needing care at one site in Edmonton alone.

Wildlife carers have been overwhelmed by orphaned young and are recruiting extra volunteers as well as moving animals to centres in cities including Brisbane.

Tim Pearson, a consultant wildlife ecologist specialising in flying foxes, said more frequent and severe heatwaves were a danger for the animals.

“What’s scary about this one is the spectacled flying fox has been hit,” he said.

“As far as we know, they’ve never suffered heat deaths before.”

In 2015, Humane Society International (HSI) nominated the spectacled flying fox to have its threatened status upgraded from vulnerable to endangered.

The threatened species scientific committee (TSSC) gave advice to the former environment and energy minister Josh Frydenberg in early 2017, but he delayed making a decision on the listing three times.

The advice of the TSSC is not public and the new environment minister, Melissa Price, now has until 7 January to make a ruling.

Evan Quartermain, the head of programs at HSI, said the species needed urgent help.

“Government inaction for our threatened flying foxes is beyond a joke, with the recovery plan that could have helped stop these mass deaths overdue by more than 12 years and nowhere in sight,” he said.

“The time to act was a decade ago, and we can’t wait a moment longer.”

“This is an unprecedented and shocking heat-stress event, with climate change seeing threatened species never before affected dropping by the thousands and dependent pups left motherless.”

Comment was sought from Melissa Price.