As for the birds and that, if you're feeding the cat she's much less likely to go after them. Cat's aren't stupid, and they tend to like to take it easy, even feral cats.

This one sounds like it rather fancies an easier life style anyway, and she's probably young enough to adapt.

Strays aren't quite the same as feral, but a stray who's had to look after itself for a fair time isn't that different - and we've has a couple of cats like that. One of them we adopted when she was pregnant, and they were lovely kittens. Then we had her spayed - but soon after, when she was off wandering, she was run over and killed. Here's a picture of the kitten we ended up keeping, Joshua. (He is waiting for Christmas Dinner.)