Cats. They are everywhere. Prowling down alleyways. Stretched out, sunbathing, atop garden walls. 

Some people find it charming. Humans adore cats. We have kept them as pets for millenniaThousands of years., and today we own hundreds of millions of them. They make for some of our most beloved characters, from Puss in Boots An Italian fairy tale about a cat who uses trickery to gain power. to DoraemonA fictional character in a Japanese anime and manga series. Doraemon is a robotic earless cat who travels back in time from the 22nd Century. . 

But wildlife lovers argue that the cats roaming freely through the world's towns and cities are an environmental catastrophe in the making. People forget, they say, that the furry felines of today are descendants of the fierce Near Eastern wildcat.

Many domesticated cats have retained this killer instinct: in the UK alone, cats kill up to 27 million birds every year.

The problem is not a new one. As long ago as 1894, a cat named Tibbles was blamed for single-handedly wiping out a small, flightless bird on Stephens Island, New Zealand. 

But today, attitudes are changing. More and more nations are becoming strict on cats. As of October 2022, cats in Melbourne, Australia, face a curfew that prevents them from leaving home. Last year, Poland classified domestic cats as an "invasive alien species". 

Some are arguing for a more drastic solution. In 2016, the authors of Cat Wars declared that the "cuddly killers" should be reined in "by any means necessary".

Their arguments ruffled many feathers. One reviewer called the book "sensationalist, one-sided [and] utterly anti-cat". 

And some say the danger posed by cats is overstated. Even Britain's Royal Society for the Protection of Birds agrees that the birds killed by cats are likely to be weak or sickly. "If you were to draw up a list of challenges facing our native wildlife," declared one RSPB official, "cats would not be near the top." 

Yes: Cats are a conservation nightmare. They kill small birds and mammals at an astonishing rate in both cities and the countryside. The world is finally waking up to this problem. 

No: Cats bring great joy and companionship to millions of people across the planet. And anyway, birds face bigger problems - like climate change, habitat loss and illegal hunting. 

Or... There is no need to reduce the number of cats in the world. But to protect wildlife, they should be kept indoors. Anyone who wants to take their cat outside should build a catio or buy a lead.