Australia lost 10 per cent of its grey-headed flying fox population last month, and over the weekend hundreds more died in the extreme heat.

Babies are particularly affected by temperatures which are routinely exceeding 40 degrees this summer.

Like koalas, when it becomes too hot, flying fox babies make their way down from the trees.

They are searching for water and cooler areas.

The forest floor is bone dry and the ground is littered with their corpses.

Many animal rescuers across the country spent their weekend spraying down the babies, desperately trying to save a portion of this year’s offspring.

With most volunteers’ homes already at full capacity with patients, it’s a struggle to take any more bats into care.

The only option is to rehydrate bats and return them to the trees rather than take them into care.

View photos Rescuers work to save dying baby grey-headed flying foxes. Source: Michael Dahlstrom / Yahoo News Australia More

At Wyoming, 53km north of Sydney, volunteers were sent into steep bush with spray bottles to try and cool those falling from the trees.

Dry leaves and branches crack underfoot, the cries of dying bats are deafening.

It’s hard to access the animals as the area is overrun with invasive lantana which is scratching up volunteers from WIRES and Wildlife ARC.

At first it’s hard to see the falling babies, but once you see one, you notice that they’re everywhere.

Those that can still climb are given water and then released. The rescuers place the dying in cages or strap them to their bodies.

The flying foxes were then brought to a makeshift triage area between two suburban houses and injected with fluids.

View photos A baby flying fox undergoing treatment in Wyoming. Source: Michael Dahlstrom / Yahoo News Australia More

View photos Dead flying foxes litter the ground. Source: Michael Dahlstrom / Yahoo News Australia More

The sickest and youngest were prioritised while the rest were cooled with wet towels.

Red-faced and soaked in sweat, WIRES volunteer Mandy Mitchell was working to rehydrate the screaming, dying animals as she spoke to Yahoo News Australia.

“We’ve only had one adult (die) so far, we’ve probably got 20 babies so far, but we’ve only just started,” she said.

“We’ve only just started, we’ve only just touched the surface.”

By the day’s end 100 babies had been treated for dehydration at Wyoming alone.

Volunteers overrun with calls and patients

Across the area, calls from concerned homeowners kept phones of rescue groups busy.

A call came through about a baby bat clinging to a clothesline. It was dead on arrival.

Another was picked up stuck in a barbed wire fence. Carers say this is a common occurrence.

View photos An emaciated flying fox lies dead in a dam after attempting to drink. Source: Jacky Hunt More