Victoria’s tiny population of rare brush-tailed rock wallabies has increased, with remote cameras revealing four new joeys in a family group at the Grampians National Park.
Only a small number of these critically-endangered wallabies still live in the wild in Victoria, and these new joeys mean there are now 13 of these wallabies living in the Grampians, traditionally known as Gariwerd. There are also about 50 wallabies in the Snowy River National Park.
Known as the acrobats of the marsupial world, brush wallabies leap around on rocky outcrops and cliff ledges, and can scale almost vertical rocks. They can also climb tall trees with their sharp claws.
The last wild brush-tailed rock wallaby was removed from the Grampians 11 years ago to become part of a captive breeding program and wallabies were re-introduced to the park in 2008.
About 30 rock wallabies were introduced over the next four years, with the aim of establishing a self-sustaining population, but they didn’t flourish as hoped, says Derek Sandow, coordinator of the Grampians Ark program for Parks Victoria.
“Predators like foxes and feral cats are a big issue, as well as introduced herbivores like goats and deer that compete for food,” Mr Sandow said.
Two years ago, several heat and motion-activated remote cameras were installed so that Parks Victoria staff could monitor the wallabies, including two new males introduced from a captive breeding facility at Mount Rothwell.
Mr Sandow admitted checking on the wallabies from his office became a daily ritual: “I was looking at the development of pouch young and trying to identify new animals.”
Last year he noticed pouch “bulges”, but no young were born - macropods like kangaroos are able to “suspend” their pregnancy through a process called embryonic diapause.
But this year, after decent rain and no significant bushfires in the area, four babies were born.
“It’s incredibly exciting to see these endangered joeys that have been born in the wild from within this small colony,” he said.
A researcher studied the DNA of the wallabies’ scats, and determined there were four more animals than originally thought, bringing the total to 13.
The Grampians Ark project was set up to protect threatened mammal species in the Grampians, including the long-nosed potoroo, southern brown bandicoot, heath mouse and smoky mouse.
Of the 15 species of rock wallaby in Australia, most have disappeared from their original range and are now considered threatened. Australia has the highest rate of mammalian extinction in the world.