"There is a remote island in the south Pacific that had a lighthouse built on it in the 1700s. The keeper kept a cat to keep him company. Everyday the cat would bring the keeper a dead bird. The keeper had never seen birds of this type before, so he kept the tiny carcasses to show scientists who'd be on exploration ships. The scientists determined that they were flightless songbirds - the only known species of flightless songbird ever discovered, then and now. One day the cat just stopped bringing the birds to the keeper. One cat caused the extinction of an entire unique species. No one ever saw a living specimen and no one ever heard their song."