Feral foxes and cats eager for a quick meal in the wilds of central Australia have a new formidable obstacle to contend with.

The Australian Wildlife Conservancy (AWC) has put the finishing touches on the world's largest cat-proof fence, a 27-mile-long enclosure of electrified wire and netting encompassing more than 23,000 acres. Called the Newhaven wildlife sanctuary, this former cattle station has been transformed into a haven for 11 critically endangered marsupials, birds and other threatened species.

"The bush will be alive with bilbies, burrowing bettongs and mala, not with feral cats," Australian Wildlife Conservancy CEO Atticus Fleming said in a recent interview with The Australian. "That's what the early explorers saw, and that's what the [local] Warlpiri people remember. In this small part of the continent we will put that back together ... I think at Newhaven we are, in effect, trying to turn the clock back a couple of hundred years."

The crushing toll of invasive species

Introduced to Australia in the early 19th century, cats have had a dramatically significant impact on ground-nesting birds and small mammals. A recent estimate based on results from nearly 100 studies across Australia found feral cats responsible for 316 million bird deaths (with pet cats contributing 61 million kills) annually or more than 1 million per day. And 99 percent of these deaths were linked to native species, including 71 threatened species.

Mammals have fared no better, with the extinction of 20 native Australian mammal species linked to feral cats and nearly a dozen more in the crosshairs.

"Whenever you start doing the maths on cat predation, the numbers are so massive, so horrendous, you think 'My God, that can't be right,'" Dr. Sarah Legge of the Threatened Species Recovery Hub told The Weekend Australia Magazine.

The rise of feral-free islands

In an effort to turn the tide against wild populations of feral cats, estimated to number between 10 and 20 million across Australia, conservation officials are in the process of constructing at least 11 large-scale fenced sanctuaries. Even Newhaven is planning on expanding its world record enclosure from 36 square miles to between 270 to 386 square miles.

"The second stage will be a minimum of 70,000 hectares (173,000 acres)," Fleming told the Guardian. "It might end up bigger than that. So a minimum of another 135km (83 miles) of fence line."

You can watch a time lapse of some of the Newhaven fence construction below.

The AWC estimates that the Newhaven sanctuary alone will help increase global populations of threatened mammals like the black-footed rock wallaby and western quoll from between 4 percent and 450 percent. Until better trapping or management of the feral predator population is enacted, Fleming says fenced sanctuaries offer the best hope for the country's native species.

"When you get rid of the foxes and cats, these native mammals breed like rabbits," he added. "This is what Newhaven is all about. Even though you’re putting a fence around it, you’re doing that to recreate natural conditions. The irony is that it's the area outside the fence is unnatural because it's full of cats and foxes."

Michael d'Estries ( @michaeldestries ) covers science, technology, art, and the beautiful, unusual corners of our incredible world.