Cat lovers in Poland have been outraged by the classification of the domestic cat as an alien and invasive species by the Nature Conservation Institute of the Polish Academy of Sciences, citing that cats cause damage to populations of birds and other wildlife. The domestic cat, by its scientific name the cat 1787 was included in the institute’s national database as an invasive species.

Given how many mammals and birds domesticated cats kill, there is a growing scientific consensus that domesticated cats harm species diversity, explained Wojciech Solarz, a biologist at the Academy of Sciences, which considers the public. “Mainly responsible” for the astonishing classification. According to the scientist, cats “meet 100 percent of the criteria to be classified as an alien invader.”

Wojciech Solarz had to defend his position against a vet in a televised debate the other day. Dorota Suminska, author of The Happy Cat, says cats are unfairly blamed for many other causes of bird deaths, such as polluted air or the “bird-killing” facades of some city buildings.

Some media reports have given the wrong impression that the Nature Conservancy is recommending euthanizing cats, according to the biologist under fire. In a recent post on its website, the institute emphasized that it opposes all forms of cruelty to animals and that the classification of domestic cats complies with EU directives.

The statement argued that the cat may have been domesticated about 10,000 years ago in the cradle of the great civilizations of the ancient Middle East, so from a purely scientific point of view the animal could be considered an alien species in Europe. According to the institute, they only wanted to recommend that owners let their cats outside for shorter periods of time during the breeding season.