Is it OK if i get a bird when i already have a cat?

My best friend has two cats and two atiels. She just makes sure that the birds' cages are shut securely when she's not in the room. And she usually doesn't have the cats inside when she lets the birds out to play. Budgies can be alot of fun because they are very smart but be sure to get one that had been "hand" tamed so that it won't bite you.