Gareth Morgan: In New Zealand, our endemic species are in a spot of bother. Originally there were no predators here, but we now have an enormous number of species that were introduced when the settlers came – weasels, stoats, ferrets, rats, mice and cats and dogs. And increasing numbers of our endemic species are driven to extinction, particularly ground-restricted birds. We’re having to move them to islands. I funded a project on the Antipodes Islands to get rid of all the mice. Next I’m looking at New Zealand’s third largest island, Stewart Island, where the three species causing the bother there are feral cats, possums and rats. In the course of the research, I thought about the role of cats on the mainland. All I’ve done is try to raise awareness of it, and this thing has gone viral.

Tom Cox: It has. I’ve written a couple of cat books, and on my Facebook page I’ve had endless people sending me links to newsclips about you. I suppose I’m talking from the perspective of someone who lives in Britain, and we have very different wildlife here. The thought of keeping my own cats indoors – that feels like I’d be their prison officer. I don’t think I could do that. But it does break my heart when one of my cats gets a bird, which is quite rare – as a preventative measure, I put bells on their collars. It seems like the majority of the cats that are killing birds here are stray, so a less extreme way to control this would be to encourage people to neuter their cats. There are a ridiculous amount of stray and unwanted cats in this country, because people have been unaware of what having a cat involves, or it’s been an ill-thought-out birthday present. My 17-year-old rescue cat was originally dumped on the hard shoulder of the motorway in a plastic bag with several of his brothers and sisters.