The respected scientific institute of the Polish Academy of Sciences (PASIFIC) has officially classified cats as an “invasive alien species,” according to the Associated Press. The study, led by PASIFIC biologist Wojciech Solarz, found that the damage caused by cats in terms of hunting and killing birds and other wildlife was reason enough to consider the animals invasive. The species “Felis catus,” also known as the house cat, was listed in a national database supported by the academy’s Nature Conservation Institute — which maintains 1,786 other species — and heard no objections to it. But the public has reportedly responded to this new entry with utter disapproval. The scientist told the AP that the public may have been upset by false accusations that the institute was pushing to euthanize the feral cats. Fox News Digital has reached out to the state-run Polish Academy of Sciences for comment. Cat owners, the Polish Academy of Sciences suggested, should limit the time their pets spend out of doors during the bird breeding season. Shutterstock The cat “100%” met all the criteria to land on the invasive species list, Solarz argued, because of the animals’ harmful effects on biodiversity. In an appearance on independent television station TVN, Solarz reported that cats kill 140 million birds in Poland every year. The institute addressed the controversy on its website last month, emphasizing the academy’s opposition to animal cruelty, the AP reported. The institute stressed that it was only recommending that cat owners limit the time their pets spend outside during the bird breeding season. Becky Robinson, president and founder of Bethesda, Maryland-based Alley Cat Allies — a leader in a global movement to protect cats and kittens — is skeptical, however, that other parts of the world, such as Australia and New Zealand, won We are not continuing efforts to get rid of cats. “Make no mistake: Labeling cats invasive is a preferred first step in a broader strategy to kill them in massive numbers through gruesome cat hunts and poisonings,” he said in a statement to Fox News Digital on Tuesday. “This idea of killing cats will never be accepted by the compassionate society we live in,” Robinson said. “It will never be efficient to kill cats, nor will it be morally acceptable.” Robinson said biologists and environmentalists have shown that other factors, such as climate change and habitat destruction, are the main cause of species loss – which makes it “completely inappropriate” to blame cats, she said. Cats kill 140 million birds in Poland every year.Shutterstock The institute’s guidelines for limiting the amount of time cats spend outside run counter to the makeup of the species, Robinson argued, as cats have lived alongside humans for thousands of years. Only recently, he said, have they started living indoors, given the invention of kitty litter in the last century. “There is no future in which humans can exist without cats. They are here to stay,” he said. “The only way forward is through humane, non-lethal programs like Trap-Neuter-Return, the scientifically proven approach to effectively and humanely deal with community cat populations,” he said. The Associated Press contributed reporting to this piece.