Feral deer invasion of South Australia at tipping point
Millions of deer have already overrun Australia’s east, and now their threat has reached a tipping point in SA. See our special interactive of SA pests.
SA News
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Feral deer are emerging as the state’s next big pest animal problem, but SA scientists are working on a solution.
Biosecurity SA’s principal biosecurity officer Brad Page is leading research on an invention called a “deer aggregator” to improve the efficiency of pest-control measures before it is too late.
“In Victoria, there are one million of them, wild,” Dr Page said.
“In South Australia, there may be less than 50,000. But they are at the point where, if we can’t get groups of landholders to get onto them and cull them in a serious way, deer are going to be unstoppable in this state.”
Along with hot spots in the Mount Lofty Ranges and around the Coorong, deer were “everywhere, from Penong (in the west) across the state, just in low numbers”, Dr Page said.
“If you’re seeing one or two, or five or 10, then in five years’ time, you’ll be pleading for advice on how to get rid of mobs of 100 or more.”
Under the Landscape South Australia Act, landowners are responsible for the control of pest animals on their property.
But in the case of feral deer, the State Government has co-ordinated additional culling in those hotspot areas.
At the base of the Fleurieu Peninsula, it was not unusual to see mobs of 50 to 100 deer, Dr Page said. Nearly 1000 were culled there in the past 12 months, and a further 3000 were culled in the Coorong.
Shooting is the only way to eliminate this serious pest. But that is easier said than done.
Deer are elusive, “timid and skittish” nocturnal animals, and were easily spooked.
Dr Page is leading research that promises to improve the efficiency of culling programs, using a feeder that is attractive to deer, but not other animals.
The deer aggregator is based on a design developed in NSW for goats and deer, but worked best for goats.
The idea is to target only deer, so that so that shooters can then go in and knock off more than one at a time.
It does not trap the deer, so they can still run away and return to feed again.
The structure exploits the differences in the sizes and shapes of the feet of native herbivores – kangaroos and wallabies – compared with the “stiletto-like” hoofs of deer, which fit through the grid.
When the long feet of kangaroos or wallabies walk on the grid, the feeder shuts.
The Centre for Invasive Species Solutions funded successful trials of a prototype in 2019; now large-scale field testing is underway in areas with high densities of feral deer, kangaroos, possums and other animals.
“We’re looking to develop a product that can be commercially provided to farmers around the country,” Dr Page said.
“We need it to work perfectly.”