Study may prompt claws for complaint

PUBLISHED : Tuesday, 05 February, 2013, 12:00am
UPDATED : Tuesday, 05 February, 2013, 2:36am

Now we know why there is so much affinity between humans and cats: we are both mass killers. Next to us, it seems, those fluffy, cuddly kitties may be the greatest threat to mammalian and avian wildlife. That is at least according to a widely reported study in Nature Communications, part of the prestigious science journal's family of publications.

The study by scientists from the Smithsonian Conservation Biology Institute and the US Fish and Wildlife Service throws up some unbelievable numbers. It claims strays and pet cats that roam outdoors at least part of the day together kill a median of 2.4 billion birds and 12.3 billion mammals a year in the United States alone.

If its estimates are right, you can imagine - or rather barely imagine - what the total worldwide kill rates are. This could be the cause for at least a few wildlife extinctions. And we are not talking about pests like rats, but shrews, chipmunks and voles.

But is the study to be believed? Should you trust those screaming news headlines from last week, including an editorial in The New York Times?

As a proud owner of six cats, I feel obliged to defend my feline friends' honour. As a sceptical journalist, I can cite reasons to justify reasonable doubts about the study, or at least its key numbers.

The researchers have impeccable scientific credentials. But what they did is called a meta-study, that is, it is not original, empirical field research, but a study of previous research results. Now the researchers admit they have no reliable numbers on strays in the US. Furthermore, the kill rates of pet cats that go outdoors are partly based on projections of previous local studies to a nationwide guesstimate.

I don't doubt that cats do kill a lot when they have the chance. They are also sadists who like to toy with their prey before killing it. My cats are all kept indoors, but my sister's outgoing cat in Canada brought home dead rabbits on at least two occasions to show off.

We should, however, treat the study's conclusions with a pinch of salt. The danger is that it will be used as an excuse by cat-hating people to call for elimination of all the strays. God knows there are enough of those people in Hong Kong when a far more humane and efficient way is to trap, neuter and release the beasts.