The RSPCA has been swamped with 86 flying foxes that were knocked senseless by hail in Brisbane's western suburbs.
About 30 have been put down and the rest are going out to carers.
RSPCA wildlife rescue officer Annette Colling said 300 to 400 flying foxes from a Mt Ommaney colony might have been killed.
They came ashore with the convicts, sailors and marines on the First Fleet in 1788. Black rats were the first of Australia's unwelcome arrivals that have disrupted ecosystems and wiped out wildlife across the land.
Now researchers at the University of Sydney have shown how the rats' quick learning and keen sense of smell can be exploited to dramatically reduce their attacks on native birds. Dr Catherine Price and Associate Professor Peter Banks say the technique could be adapted to protect vulnerable species around the world.