The first class of the Possum Finishing School have graduated and were released into the wild on Thursday, as part of a five-year research project.
Since June 2019, Fostering and Assistance for Wildlife Needing Aid have worked with the South West Catchments Council, Department of Biodiversity, Conservation and Attractions, UWA and vets to assess, microchip and register possums in a location before releasing them into bush land.
SWCC cultural development manager Jacqueline Lahne said they released 20 critically endangered western ringtail possums including 10 males and 10 females into the wild.
Ms Lahne said all of the possums came into the care of wildlife rehabilitators as pouch young as a result of abandonment or their mothers being killed.
"Once raised to weaning the animals were cared for in the Possum Finishing School which is run and staffed by volunteers from FAWNA. The animals had been in the Finishing School for two to three months prior to release," she said.
"The conditions that possums are exposed to whilst being cared for in the home of wildlife rehabilitators can vary considerably.
"Some animals are kept inside, while others are kept outside in large cages. Some are exposed to dogs and cats that people have as pets and others are not. The level to which rehabilitators handle the animals also varies considerably.
"While at the Possum Finishing School the conditions for all of the animals are the same and are intended to prepare them for release as best as possible. This includes the minimisation of human contact.
"Our hope is that they will all survive and go on to breed and contribute to the ongoing survival of their species, however it is a realistic assumption that a proportion of them will not survive.
"The purpose of the study is to understand how treatment before release affects their survival rates so that we can give them the best possible chance."
The majority of possums that come into care are pouch young and have been orphaned or abandoned as a result of road trauma, dog and cat attacks, habitat loss or disease.
Rescued animals are kept in private homes and released in uncontrolled conditions with uncertain outcomes.
FAWNA president Suzi Strapp said the strategic pre-release process would reduce stress on the animals and lead to more efficient use of time and resources.
"All FAWNA western ringtail possums will be microchipped so the fate of possums raised in care may be monitored beyond the six-month lifespan of radio collars," she said.
"We are overjoyed that we will finally have scientific evidence-based outcomes to help us develop best practice approaches in rescue, rehabilitation and release of these precious animals."
Endemic to the South West, the western ringtail possums are listed as critically endangered with less than 8000 individuals in the adult population.
The SWCC have developed a new database to gather essential data throughout the life of captured possums, including their experiences post-release.
Researchers will seek to understand the fate of orphaned pouch young which are raised by carers to see what release methods and site characteristics impact their survival.
