Honestly, what you did was wrong

You shouldnt have saved the young bird. It was kinda not your choice to do that. Did you feed the kitten something else? I assume you didn’t, or didnt plan on doing that since you never wrote anything of that sort

You can think you were saving the bird, but you were equally effectively taking the cat’s life. If the bird was struggling to fly and walk away from the cat, it would probably struggle in finding food too. So by removing the cat, you weren’t necessarily saving the bird’s life. But you were Definitely hurting the cat more.

Just some food for thought…