They look innocent, but the damage they can do is enormous. We are talking about domestic cats. As reported in the NZZ, they pose a serious threat to biodiversity. Driven by their natural hunting instinct, they are capable of endangering or even wiping out entire species. They adapt their eating habits flexibly to their environment, which is why they target not only specific species but also anything that crawls or flies.

In Scotland, a ban on keeping domestic cats is already being discussed to curb the harmful impact. The debate is not new in Switzerland either. Last year, the association Climate Protection Switzerland proposed a cat moratorium to ban the breeding and import of cats and thus stop the population from growing. This would enable the regulation of an invasive species spread by humans.

It is clear that cats are not just the lovable pets they are often thought to be. A study in the journal Nature Communications shows that feral cats, in particular, are responsible for the majority of birds killed by human influence. Worldwide, cats hunt more than 2,000 different species, with almost 350 of them considered threatened, according to a recent metastudy also published in Nature Communications.

Cats kill 30 million birds a year

In Switzerland, the Federal Office for the Environment estimates that cats kill around 30 million birds and half a million reptiles and amphibians every year. These figures are controversial because they are based on extrapolations, but one thing is clear: cats pose a serious ecological problem and are responsible for the extinction of at least 33 species worldwide.

There are various approaches to reducing the negative impact of cats on wildlife. One measure that has proved promising is to wear collars in eye-catching colours with bells that warn prey before the cats strike. One study showed that cats with such identification caught 37 per cent fewer birds.

Another option is to satisfy the hunting instinct with a high-protein diet and daily play sessions. Research suggests that such approaches can reduce the number of wild animals killed by up to a third.

One thing is clear: cats' hunting instinct must be curbed. Fortunately, their ecological footprint can be reduced without drastic measures such as house arrest or bans. Such measures would probably have little chance anyway – after all, the cat lobby should not be underestimated: according to the Tagesanzeiger, around 30 per cent of all Swiss households have at least one cat at home. Unsurprisingly, no politician wants to touch this hot potato.