Cats categorised as 'invasive alien species' by Polish scientist, but why?

A respected Polish scientific institute has classified domestic cats as an “invasive alien species”, citing the damage they cause to birds and other wildlife. Some cat lovers have reacted emotionally to the decision and put the key scientist behind it on the defensive. Wojciech Solarz, a biologist at the state-run Polish Academy of Sciences, wasn't prepared for the disapproving public response when he entered “Felis catus”, the scientific name for the common house cat, into a national alien species database run by the academy's Institute of Nature Conservation. https://www.euronews.com/green/2022/07/27/cats-are-alien-species-says-polish-institute