This is impossible to guarantee or control for. Birds migrate, you never know who might make a pitstop at your feeder. I've spotted birds that were so far off their normal range it created a buzz in the local birding community. There's a non-zero chance something endangered or at least very rare could stop by your feeder.

If you're worried about making sure your cat gets enough stimulation there are a lot of articles and tips on things you can do that require little effort on your part (like, even a cardboard box full of crumpled paper can do the job).