My mom breeds Bourkes and gave me one to add to my mini-aviary (24"x36"x48"). The bourke is a little larger than the parakeets you see for sale in the petshop. While you could keep it in a small cage, I wouldn't advise that unless you can give it attention, play with it, and give it flight time on a daily basis. We discovered that the behavior of the bourke is quite different when it is in a small (18"x18"x24") cage compared to a larger cage (24"x36"x36"). In the smaller cage the bourke just sits. But in the larger cage, the bourke plays with bells, hops and flies around, and chatters. It made us feel a little guilty once we saw the peppiness of the bourke in the larger cage.