I wouldn't worry about the crows, if that's the kind that she is chasing. I would only be concerned about the smaller song birds, because it's true that our non-native cats do devastate the native song bird population. The worst that Akira can do, though, is watch them, because the furthest outside she can go is the small balcony. She can't really get a running start to catch birds, so all she can do is startle them. Plus, I supervise her when she is out on the balcony when the weather allows it, because I'm very protective of her and don't want her to fall off the balcony. Most of the time she just suns herself when she is out there, so it's all good.