Wildlife rescue organisations across New South Wales are facing an unusual influx of premature and severely underweight flying fox pups, raising concerns about the health of grey-headed flying fox populations during the spring birthing season.

Since late September, wildlife rescue groups have received more than 460 reports involving malnourished grey-headed flying foxes in what is being described as a suspected starvation event. Volunteers say the number of premature births and sick animals arriving for care is far greater than they would normally expect at this time of year.

On the NSW South Coast, volunteers have been responding to reports from the Shoalhaven region, where sick, deceased and prematurely born pups have been found at roosting sites and residential properties. Some newborns have been discovered weighing less than half the expected healthy birth weight.

A newborn flying fox would normally weigh approximately 80 to 90 grams, according to wildlife carers quoted in the report. One premature pup weighed just 38 grams. Animals born at such low weights face serious challenges surviving outside the womb and may require intensive care.

For Australian Wildlife Needing Aid NSW, known as FAWNA, estimates that approximately 95 per cent of prematurely born pups entering care may die. This reflects the severity of the situation facing rescuers, although the final mortality rate will not be known until the current crisis has passed.

Wildlife Rescue South Coast has also reported a substantial increase in calls. Its volunteers have been caring for dozens of premature flying foxes while responding to reports across a wide geographical area. Some pups need feeding every two hours, around the clock, creating significant pressure on a relatively small team of trained carers.

Handling flying foxes requires appropriate training and precautions because of the risk of diseases, including Australian bat lyssavirus. The cost of the required vaccination can limit the number of volunteers available to respond to emergencies. Rescue groups say staffing shortages, long travel distances and the volume of calls are making the response particularly difficult.

Scientists and wildlife carers are still investigating what caused the apparent starvation event. A possible explanation is a temporary shortage of suitable food, but authorities have not confirmed the cause. Testing of flying fox carcasses recovered in the Illawarra reportedly found that the animals were severely emaciated when they died.

Grey-headed flying foxes play an important role in Australian ecosystems by pollinating flowering trees and dispersing seeds. A significant decline in their population could have consequences beyond the immediate loss of individual animals.

Wildlife rescuers are continuing to provide emergency care and document cases, but the full scale of the event remains uncertain. Authorities and specialists will need more information to establish what triggered the premature births and whether food availability, environmental conditions or other factors contributed.

The immediate priority is caring for surviving pups and supporting wildlife volunteers. The cause of the event remains unconfirmed, and the final number of affected animals is not yet known.