Killer Cats.

All cats are predators. It's just that some are better at it than others. My present cat is very good at catching mice - which she always brings into the house to finish them off. She had a bad experience with a bird some years ago. She was stalking a baby blackbird in the garden. The mother bird was perched just above them and launched a full-on attack on the cat. My cat screamed and ran into the house! She very rarely goes for birds since that time.