Protecting vulnerable natives from ferals

Adult and juvenile brolga foraging at water's edge. Photo by Steven David Miller / Auscape International Pty Ltd

On Naree Station in northwest New South Wales, the day has dawned clear and bright. In the cane grass swamp behind the homestead, brolgas are picking their way through the shallow water on their long stilt-like legs.

They’ll spend much of the day there peacefully foraging for food – digging into the mud with their powerful bills.

For Bush Heritage Reserve Managers David and Sue Akers, who live year‑round on Naree Station, the sight of these stately native birds on this morning is a good omen.

Soon David and Sue will travel across Naree’s vast alluvial floodplains to a semi‑permanent waterhole where they expect a less welcome sight – feral goats. Like stray cattle and sheep, which the Akers have worked hard to remove since the purchase of Naree two years ago, goats can cause significant damage to Naree’s fragile soils and vegetation.

Rather than scouring Naree’s 14,400 hectares for stray ferals, the Akers have been systematically shutting down artificial water points across the reserve – effectively using the goats’ reliance on water to lure them to a specific location. This makes it easier to both locate and remove them in sizeable numbers.

A feral cat devours a native bird. Jiri Lochman / Lochman Transparencies

There they will meet neighbours with their sheep dogs, motorbikes and sometimes even a gyrocopter, to muster the goats into temporary yards from which they will be trucked off and sold.

The relative ease with which these goats will be removed is testament to Bush Heritage’s approach to feral animal control: our aim is to use the funds our generous supporters provide as effectively as possible by working smarter.

Feral animals like pigs, cats, foxes, rabbits and goats are a permanent feature of the Australian landscape, causing untold damage to native species.

In the relatively short period since European settlement we’ve lost 29 of Australia’s unique mammal species – with 89 more species and subspecies now at risk. In many cases feral animals are contributing to the decline.

In Victoria, on our Nardoo Hills Reserves, Global Positioning System (GPS) technology has been used in effectively controlling rabbits. When Bush Heritage supporters helped us purchase the first of the four properties that comprise Nardoo Hills, rabbits were threatening the future of its temperate woodlands.

This series of motion sensor triggered photographs on Carnarvon Station Reserve demonstrates how perilous life is for native animals faced with predation by ferals.

These are the most threatened woodland ecosystem type in Australia, containing rare native orchids such as the northern golden moth orchid (Diuris protena) and the critically endangered robust greenhood (Pterostylis valida).

Nardoo Hills Reserve Manager Jeroen van Veen has seen rabbit numbers plummet across three of the reserves to virtually nothing in 2014.

In 2007 we had 280 active warrens. Now we have about six – and they’re on the outskirts of the reserve where we get the occasional ‘immigrant’.

“Our first property was purchased in 2004 and rabbit control began about a year later,” says Jeroen. “We walked the properties with a GPS which allowed us to accurately pinpoint the location of each warren decommissioned.

We then checked them regularly for any renewed activity. Initially we did this a couple of times a week, then every few weeks, then every couple of months.

Feral goats trapped in a temporary yard . Photo by Nick Rains / Auscape International Pty Ltd

Rabbits operate on a hierarchical burrow system, so as soon as a better burrow becomes vacant, they’ll move into it. The best burrows are targeted and decommissioned again and again, until no more rabbits remain.

Similar GPS‑based systems are used on other Bush Heritage Reserves with substantial rabbit populations, including Scottsdale in New South Wales and Bon Bon Station in South Australia.

At Scottsdale the work is completed by dedicated volunteers who return four times a year to ensure the rabbits don’t get a chance to re‑establish.

Technology is also being used to help us work smarter controlling feral cats on Boolcoomatta – our other South Australian reserve.

Here, thanks to the ingenuity of volunteers Keith Gooley and Peter Calder, Reserve Manager Glen Norris now has an electronic alarm system, which alerts him when any of his cat traps are activated.

Feral pigs are highly destructive to wetlands and waterways, and other habitats. Photo Jiri Lochman / Lochman Transparencies.

Control of both predatory feral cats and foxes is crucial on Boolcoomatta, which provides sanctuary for species like the endangered plains wanderer – a small quail‑like bird found on its open grasslands, and the nationally vulnerable dusky hopping mouse.

“We have traps on the reserve that are connected to a transmitter. I’m notified, using the UHF radio network when a cat gets into a trap,” says Glen. “It’s such a timesaver because previously I had to check all the traps manually.”

Depending on which feral animals are present, our control methods vary on each reserve but each is informed by science and continually improving.

While our methods are sound, feral animal control is an ongoing challenge with no end in sight. It’s a continuous process that requires substantial resources, dedication and smart thinking.

Thankfully nature provides regular reminders – such as the sight of a majestic brolga in flight or a plains wanderer on Boolcoomatta – of the importance of this work in protecting our most vulnerable treasures.