But it's not the noise and the smell that make them different to any other room-mates in the heart of Sydney, it is that Ms Stanford's room-mates are flying foxes.

She has 29 crowded into her spare bedroom; with 15 more set to arrive. Ms Stanford is the head of the bat and flying fox team for WIRES, devoting her free time to the care and rehabilitation of the animals, thousands of which have been suffering from the heatwaves.

"This is probably a larger set-up than most people can have and I am very fortunate in that, because I don't have other people living in the house, I can afford to donate this space,'' she said.

The heat has kept her and other volunteers busy, with flying foxes dying in their thousands.

"It's just been the most hideous season,'' Ms Stanford said. ''We have had a huge season for pups; we've probably had three times more pups than we usually do and we just haven't been able to cope … and now the heat has just made everything worse again."

WIRES volunteers provide ''halfway houses'' where sick or injured bats can recover in safety, regaining their strength before being released.

Typically, flying foxes start to die if the temperature climbs above 42 degrees, meaning the record-breaking temperatures throughout January have also led to record numbers of at-risk bats and flying foxes.

Justin Welbergen, is a member of the Australian Research Council and is a Senior Research Fellow at James Cook University, he has written a PhD on the effect that extreme heat has on flying foxes.

"If it gets hot again, it will happen again, it is inevitable; every time the population is hit by one of these events, the population will be affected because flying foxes will die," Dr Welbergen said.

"When thousands of flying foxes die in these sorts of events, on top of their normal mortality rate, it puts a lot of pressure on the population."

Dr Welbergen believes that the heightened mortality rate of flying foxes due to the heat is a sign for greater ecological concern.

"The heat doesn't only affect flying foxes, it doesn't bode well for all biodiversity.

''I personally think that flying foxes are sort of like canaries in the coalmine, they are very good bio indicators of what is happening to other species.''

Dr Welbergen says no other species is responsible for maintaining biodiversity as flying foxes do.

''They are extremely important … they are the only long-distance seed and pollen dispersers and they play a crucial role in maintaining the diverse structures in forests.''