Up to 500 million mammals, birds and reptiles – including 8,000 koalas – have been killed, say ecologists from Sydney University, prompting fears entire species of animals and plant life may be lost for ever.

More than 300 baby flying foxes have been abandoned by their mothers trying to survive, experts said.

Jenny Packwood, a wildlife rescuer, told the Herald: “Mothers are abandoning babies at two weeks after birth because there is no food for them. Last week we had 300 come in, and we’ve been flat out feeding since then.

“I’ve never seen anything like this before – we’re calling it a starvation event.”