Island rats to bolster mainland population

Thirty-two vulnerable greater stick-nest rats were recently airlifted via helicopter from the Franklin Island Wilderness Area and St Peters Island Conservation Park off the coast of Ceduna to be relocated on the mainland.

The relocation plays an important role in the recovery of the species and is part of National Parks and Wildlife Service SA (NPWS-SA) bolstering the Australian Wildlife Conservancy's (AWC) reintroduced mainland population at Mount Gibson Wildlife Sanctuary.

Eyre and Far West ranger Tayla Westley said she was involved in the initial work overseeing the safe transporting of the greater stick-nest rats alongside four NPWS-SA staff and Eyre Peninsula and Alinytjara Wilurara Natural Resources Management staff.

"They are native rodents, about the size of a large guinea pig and, while they are wild animals, are quite placid," she said.

"It is necessary to handle them with great care as we have spelt out in the conditions of the project's scientific permit.

"It's very inspiring seeing how this first step of the translocation process fits in with overall national and Australian Wildlife Conservancy's recovery aims."

She said she was proud to be part of the process.

"It's definitely not an everyday activity for us, and its interesting to consider the contribution these animals can have towards improving genetics in other populations."

AWC senior field ecologist Chantelle Jackson said the stick-nest rats were translocated to the sanctuary where they were released into Western Australia's largest, introduced-predator-free area on the mainland.

"The Mount Gibson population is critical for the conservation of the species as it is one of only six surviving populations globally," she said.

"After the animals were caught on St Peter Island, each individual was checked to ensure it was healthy and met the selection criteria to be suitable for translocation.

"As we are working with threatened species, every individual is important."

She said the greater stick-nest rats from St Peter Island adding genetic diversity to the existing population and it was one of eight locally extinct species to have been reintroduced to Mount Gibson Wildlife Sanctuary.

Greater stick-nest rat's build communal nests from dead sticks about one metre high and 1.5m wide.

They construct nests with tunnels that lead from outside to the centre, where they place soft grass and other soft vegetation and live together in small family groups.

Once widespread across parts of Western Australia, South Australia and western New South Wales, greater stick-nest rats became increasingly rare until the early 1900s, after which they soon became extinct on the mainland and only a small population survived on Franklin Islands.

They often fell prey to introduced feral cats and European foxes, or were out-grazed by sheep and later by European rabbits

A breeding program established in 1985 saw species numbers increase so that they could be released to other South Australian and Western Australia islands, with island populations steadily increasing.