Best friend macaws Billy and Emma share a cage at the zoo, performing tricks for the crowds, until a scary thief steals Emma in the night, and Billy is left alone. The zookeeper's search is unsuccessful, so Billy and friend Nancy the crow fly out to look for themselves. Nancy's pigeon acquaintances lead them to the apartment where Emma is held captive. She escapes, and everyone returns to the good life at the zoo. Later, the robber returns, but Billy and Emma are able to send out a warning signal so all ends happily. This is a good transitional picture book, with a simple, appealing animal story and language well-suited to beginning readers. Hale's bright, cartoonish watercolors emphasize the birds' beauty and personalities, as well as the delicious freedom of flight. A concluding note offers more facts about bird intelligence for young animal fans.