It's a race to save about 124 species of native wildlife at risk of extinction from feral cats, which are notoriously hard to kill.

Threatened Species Commissioner Gregory Andrews said the cull, which goes until 2020, did not target domestic cats, nor was driven by bloodlust.

"They are the single biggest threat to our native animals, and have already directly driven out of extinction 20 out of 30 mammals lost," he said.

"We are not culling cats for the sake of it, we are not doing so because we hate cats.

"We have got to make choices to save animals that we love, and who define us as a nation like the bilby, the warru (Black-footed rock-wallaby) and the night parrot."

The Minister for the Environment and Energy Josh Frydenberg is expected to announce in March the first round of grants to encourage communities to trap and humanely euthanise feral cats. Mr Andrews has called on every mayor around Australia to provide free euthanasia of trapped feral cats.

Each feral cat kills up to 1000 native animals a year, ranging from crickets to lizards and small mammals. Some feral "catastrophic" cats will develop a taste and skill for hunting larger prey: Indigenous rangers in the Anangu Pitjantjatjara Yangkuntjatjara lands caught a 6.8-kilogram cat with a 5 kilogram rock-wallaby (warru) in its gut.

The speed and stealth of cats makes them hard to catch and efficient hunters of native animals. They leave few tracks, and turn their noses up at baits used to trap wild dogs.

In New Zealand, which faces a similar threat from feral cats, a single cat was found with the remains of 102 bats, all killed within a week.

Mr Andrews visited New Zealand to study community action against predators – the Polhill running group near Wellington mixes morning jogs and trail biking with checking predator traps, for instance.

He wanted to do more to encourage community groups to get involved. He cited the example of Canberra's myna bird action group, which had significantly reduced the population and in turn led to a rise in  native bird numbers. Its members spot, trap and euthanise the birds, often using carbon monoxide.

About 211,000 cats were culled last year, including dozens in Kosciusko that were preying on mountain pygmy possums, and others preying on bilbies, bandicoots, numbats and night parrots in remote and arid Australia. Five islands, including Christmas Island and Kangaroo Island, have introduced plans to gradually eliminate all feral cats and phase out domestic cats - most communities supporting initiatives where existing pets will be the last to be kept, and will often require a licence.

Other ways to cull cats being investigated include:

One of the most exciting developments is a grooming trap that targets cats' fastidious nature by spraying its pelt with toxin. John Read, an Eyre Peninsula-based ecologist, developed the trap after seeing many native species "knocked off".

When an infrared camera spots and identifies a feral cat (using complex algorithms that filter out humans and other animals) it sprays the cat's fur with a toxin.

"Cats are fastidious about grooming, and they will lick it off and ingest the poison. It is more of an instinctive thing," Dr Read said.

"All of the other techniques, luring them to a cage trap or a bait, requires the cat to make a conscious decision to go after a bait."

The RSPCA supports the humane trapping and killing of feral cats where they are proven to have reduced native species. It said poisoning with 1080 – most often used and currently in the grooming trap until a more humane toxin, called PAPP (para-aminopropiophenone) can be sourced – is not considered humane.

Other research by Dr Katherine Moseby looks at how to target "catastrophic feral and pet cats" – nearly all male and large – whose ability to kill large prey such as wallabies, quolls or in one case, even swimming after grey teal ducks can endanger a population.

A paper released in January by Dr Sarah Legge from the University of Queensland estimated the feral cat population was about 2.1 million across Australia during drought and nearly six million in wet seasons. Feral cats had spread across every part of Australia with greater concentrations on small islands, in the remote outback and in urban settings, near garbage tips.

(Mr Andrews said this proved that each cat was causing twice as much damage as previously thought.)

Dr Legge also found that cat populations were as great in conservation areas as elsewhere.

The findings made the government's cull target of two million by 2020 more challenging.

Given these findings, Dr Legge argued for the cull to be focused on the most vulnerable areas and targeting catastrophic cats.

Dr Legge said some male feral cats would specialise in hunting juvenile rock wallabies. The cat would learn how to take out big prey like a recreational fisherman angles for fish. "Then they just go for it."

While Australia had fewer feral cats than many countries, the relatively high impact of feral cats could be "because many Australia species have relatively low reproductive outputs, and/or may be unusually susceptible to novel predators "

Mr Andrews said nearly all people visiting his Facebook page back the government's plan, but he has attracted death threats from opponents.

Pet rights activists such as Brigitte Bardot have criticised Australia's plan while others say we should trap, neuter and release the animals.

Despite the threats, Mr Andrews said he had no problem sleeping at night.

"I sleep well because – having been a cat owner for most of my life – the science says every feral cat will kill three to 20 native animals a week."

"I have gutted a feral cat and seen what's inside," he said.

It was a quoll. It made his stomach churn, but gave him new respect for what cats can do.