The endangered Grey-Headed Flying Fox is being decimated in Sydney, Illawarra and Shoalhaven backyards in what is being seen as a very odd and very dangerous year for a species critical to the longer term health of our forests.

In the Illawarra, the Wildlife Information and Rescue Service (WIRES) is currently receiving up to four calls a day about flying foxes entangled in netting thrown loosely over fruit trees in people's backyards. In the Shoalhaven, the Native Animal Network Association (NANA) is experiencing similar problems.

The National Parks and Wildlife Service (NPWS) fears that many more entangled bats are either being ignored, not reported, or worse, they are being killed by people unsympathetic to fruit raiding bats.

WIRES spokesperson, Cathy Joukador, said today that it has been a very tough year for flying foxes.

"Without a doubt this season has been horrendous. We've never seen anything like the number of bats being entangled in netting in people's backyards as we have this season," said Mrs Joukador.

"We have no idea why it's so bad this year but we are speculating that there's a real natural food shortage which is why they are now raiding backyard fruit trees.

"If we are getting four calls a day in the Illawarra then there are plenty of other bats which are not being discovered and others which I fear are just being killed as pests. We are aware that entanglements are also happening in Sydney backyards and probably up and down the coast," said Mrs Joukador.

NANA bat care specialist, Ms Geradine Hawkins is also concerned by recent flying fox deaths and entanglements occurring in the Shoalhaven area.

"Tragically, these animals, once entangled, suffer a very slow, painful death and it can be avoided if people place a proper frame underneath the netting which ensures the netting is taut and not loose. The netting should be secured to the ground well away from the fruit tree.

"The worst thing is where people cover their fruit trees with loose netting and then go away on holidays. The injuries caused by the netting mean many animals have had to be put down and others may not be able to be released back into the wild. They all suffer severe stress and trauma," Ms Hawkins said.

NPWS Regional Manager, Diane Garrood appealed to all backyard orchardists to take action to prevent these threatened native animals from dying needlessly.

"Flying foxes are critical for the health of our forests. They help to pollinate trees and spread seed across the landscape," Ms Garrood said.

"They have been affected over many years by loss of foraging habitat and disturbance of roosting sites and are now listed as a threatened species. People can help their survival by taking care in how they net their fruit trees.

"Anyone finding a flying fox caught in a net or other material should call WIRES or NANA immediately. They should not try to release the animal themselves as a very small number carry a virus called Lyssavirus. Medical treatment should be promptly sought if bitten or scratched," Ms Garrood said.

She said that the best solution was to correctly net all fruit trees and follow the advice on the department's website.