Bird's eggs can be obtained from Bird nests, which are dropped from a tree while Woodcutting or obtained from the Miscellania Kingdom Management activity. In either case finding an egg is quite rare. To hatch an egg, place it in a pet shop incubator (found in Yanille or Taverley), and then wait for an hour or two before retrieving your chick (time spent offline doesn't count). When enough time has passed, a chat message will appear saying: "An egg in your incubator is ready to hatch!". Having reached adulthood, the Hawk may be placed in the Menagerie of your Player-owned house.