Five years after the last rabbit was killed, endangered birds such as the black-browed albatross are growing in numbers

This article is more than 3 years old

This article is more than 3 years old

Eight species of threatened seabird have begun to recover on Macquarie Island, signalling a possible end to 130 years of death and destruction on the sub-Antarctic outpost.

The island has been formally declared pest-free, five years after the last rabbit was killed.

The black-browed albatross, light-mantled sooty albatross, Antarctic prion and white-headed petrel, which were all listed as endangered, are now considered to be of least concern, while the grey-headed albatross has been downgraded from critically endangered to endangered.

The blue petrel was downgraded from critically endangered to vulnerable, while the southern diving petrel and south Georgian diving petrel, which were listed as vulnerable, are now listed as species of least concern.

Professor Stephen Garnett, head of Birdlife Australia’s threatened species unit, said it was the biggest one-off downlisting of threatened species in Australian history.

Birds on Macquarie Island, 1,742km south of Tasmania, have led a troubled existence since 1890, when New Zealand politician Joseph Hatch secured a deal with the Tasmanian government to harvest penguins for their oil. About 2m penguins were killed before the practice stopped in 1919.

Sealers introduced rats, cats and rabbits to the island in the late 19th century.

Facebook Twitter Pinterest The light-mantled sooty albatross is no longer listed as endangered. Photograph: PA

By 2000 the rats and cats had been eradicated, leaving the rabbits to thrive and causing widespread destruction of albatross nesting habitat.

Early attempts to remove the rabbits had a few setbacks. A number of petrels, a scavenger bird, died after eating the carcasses of rabbits that had eaten poison baits.

My PhD takes me to one of the last truly wild places on earth Read more

Rangers then released calicivirus, a disease imported to control feral rabbits in Australia. Saturday marks five years since sniffer dogs detected the presence of any rabbits on the island.

Garnett said the subsequent recovery of eight of the 14 threatened bird species on the island showed efforts to remove pest species had paid off.

“It takes substantial and sustained investment to do it but then you get a lasting result,” he said.

“You can’t just put a little bit of money in and then walk away. You need to really keep at it.”

Similar projects are under way to remove cats from Dirk Hartog Island, off the coast of Western Australia, and from Kangaroo Island, off South Australia.

Giant carnivorous mice threaten world's greatest seabird colony Read more

Another foray in feral animal destruction is occurring on Gough Island off the coast of South Africa, where giant house mice (a mouse needs to be twice as big as usual to be deemed giant, Garnett says) are threatening the recovery of species such as the giant albatross by eating their chicks.

The rabbits on Macquarie Island were not so macabre, but their incessant grazing destabilised soil on hillside nesting habits, causing land slides. For a number of species that nest in burrows that was catastrophic, Tasmanian Parks and Wildlife’s Rachel Alderman said.

Other species, such as the Antarctic tern, had returned to nesting on the rocky beaches after generations perched on stone spires off the coast to protect their eggs from rats.

Alderman manages the seabird program on the island and is due to visit again next week. She said the vegetation had made a remarkable recovery, though whether it had begun to return to its original state was hard to tell.

“We don’t have a firm basis for what the pristine island might have looked like because there’s such a long-term presence of humans and feral animals,” she said.

Alderman cautioned that while some species had recovered, they still faced threats in other areas.

“A large percentage of their life is spent at sea in places that are much harder to protect,” she said. “By no means are they all out of the woods.”