Our knowledge of how feral cats behave is growing, with some of the latest data showing they are even roaming in our alpine passes.
Forest and Bird said it proves cats should be included, alongside other predators, in Government's Predator Free 2050 goal.
A night camera has caught a cat red-handed.
"Feral cats are a problem for our native wildlife, they are killing machines," Forest and Bird's regional conservation manager for Canterbury and West Coast Nicky Snoyink said.
We know they exist and now we are getting a clearer picture of where they go.
Auckland University PhD student Cathy Nottingham tracked feral cats' movements on farms in Northland.
"What I've found is that most of the cats do seem to prefer to be in forested patches on the farms which I guess could be a space that native birds are more likely to be hanging out which is concerning," she said.
Another key piece of information is what they eat.
"Found quite a wide variety of things in their diet, so there were invertebrates, about half of the cats had birds in their diet," Nottingham said.
The research is geared towards helping people control feral cats with more effective trapping.
"Just the sheer numbers of them I think is pretty amazing as well and people aren't aware of it," Nottingham said.
Manaaki Whenua Land Care Research has also been tracking feral cats, 20 of them in the Hope River and Hawdon River, in the Main Divide.
The cats are fitted with GPS collars, and the red dots on a map show the 10-hourly movements of one cat over 245 days.
The cat had covered quite a lot of ground, up into the alpine passes and back to the valley floor.
According to the combined data of all tracked feral cats in the Hawdon Valley, one of the cats made it as far as the West Coast.
"Really compelling and revealing research they've done," Snoyink said.
Forest and Bird said this research supports evidence that up until now we've only had anecdotally.
And the Government should utilise it.
"A good solution would be to extend the gambit of 2050 Predator Free to include cats," Snoyink said.
Because they're just as damaging as stoats, rats and mustelids.