The region's budding flying fox population was not immune to Friday's scorching weather, as dozens of bats died in the heat.
WIRES volunteers spent hours on Saturday disposing of nearly 50 dead grey-haired flying foxes after they died in the hot weather.
The colony, numbering tens of thousands, had taken up a summer spot in a patch of bushland just north of the Figtree freeway exit.
Several WIRES members managed to rescue three flying fox babies, which will now be nurtured back to health.
WIRES Chairman Sam Joukador said volunteers had removed a wheelbarrow full of the dead bats and expected to find more on the other side of the freeway exit.
"The heat just brought a lot of them down ... they can't handle the hot weather," he said.
"During the last heatwave, we had the same problem but this time, the weather was a lot more intense ... if it had lasted more than one day, we would have lost about 90 per cent of the colony.
"We found a lot of them in the creek; they'd drowned while they were trying to get some water, they can't just take off and fly from a creek like that, they need to be up high.
"Unfortunately, there's not a lot we can do ... it's just nature taking its course."
Mr Joukador said residents in the area had been terrific, alerting WIRES about the dead animals and helping with the rescue effort.
WIRES bat co-ordinator Sandra Leonard is now set to care for the baby flying foxes in her Minnamurra aviary.