There has been a mass bat casualty on the North Shore

Following multiple heatwaves across eastern Australia in 2026, thousands of grey-headed and black flying foxes — also referred to as bats — have dropped dead.

Taronga Wildlife Hospital told the Lorikeet on Monday there had been a mass bat casualty in a Lane Cove bat colony in recent weeks.

The hospital said that by the time wildlife rescue services were alerted, many bats were already dead. Recently orphaned bats and other survivors were taken to experienced bat carers for rehabilitation.

The wildlife hospital also recently took in a flying fox from Gladesville with “burnt and necrotic wing injuries”. This flying fox had to be euthanised.

According to local conservationists, who have been working with bats for decades, heat is becoming increasingly deadly for the winged mammals. The recent heatwaves also killed hundreds of bats in the Illawarra.

Environmental factors: Nancy Pallin is a local mum who has been working in bat conservation since 1987.

According to Pallin, the expansive tree canopy and dense bushland found on the North Shore can provide relief for bats when the mercury soars. 

In Western Sydney, where the urban heat island effect is more pronounced, bats have endured harsher conditions. In recent weeks, North Shore wildlife carers — including Sydney Wildlife Rescue — have taken in heat-stressed bats from these areas. 

A haven in the North: Many flying foxes have found a home at the Ku-ring-gai Flying-fox Reserve, a state government-protected colony in Gordon that is monitored by Ku-ring-gai Council staff when the temperature reaches 40C.

Why are the bats dying? As mammals, bats are physiologically quite similar to humans. Their bodies react the same way to extreme heat: as their core temperature rises, organs begin to shut down, causing death. 

• Unlike humans, though, bats don’t sweat: they fan their wings and lick themselves to cool down. 

Broken hearts: According to Sydney Wildlife Rescue, in severe heat bats usually die from heart failure. Pallin recalls finding bats “hanging in low branches with their mouths open”.

During extreme heat, a bat will descend to lower branches where it is cooler. Pallin said vegetation close to the ground was crucial in providing shade and retaining moisture in the soil, which allowed bats to survive.

Heat an ongoing problem: This January, New South Wales, Victoria and South Australia saw record-breaking temperatures. 

According to data from World Weather Attribution (WWA), in the pre-industrial period (1850–1900) similar heatwaves occurred once every 25 years, whereas today it is every five years. 

WWA says its work with scientists “quantifies how climate change influences the intensity and likelihood of an extreme weather event in the immediate aftermath of the extreme event, using weather observations and computer modelling”.

Lucky this time: While bats seeking shelter in Ku-ring-gai appear to have survived the recent scorchers, it has not always been so.

• “We’ve had years where there've been hundreds dead during extreme heat events,” Pallin said.

She described these events as grim. “Usually what is found is piles of bodies … 2013 was a particularly bad time, there were hundreds.”

Pallin has been working with local bats in the Ku-ring-gai for over 43 years. She says that in that time the problem of heat-related deaths has worsened, a view seconded by Sydney Wildlife Rescue.

Note: A previous version of this story stated that there had been no recent reports of bat deaths on the North Shore. After publication, Taronga Wildlife Hospital reported a mass casualty event to the Lorikeet. The story has been amended to reflect this information.

Thumbnail: Thea Harrison via Unsplash