 In these countries, it is against the law to rehabilitate (or in some cases possess) a wild animal without permits.In the United States, rehabilitation permits, requirements, and procedures for all animals other than birds vary from state to state.Rehabilitation of birds in the U.S. requires, per the Migratory Bird Treaty Act, that a permit be obtained from both the state wildlife agency and the United States Fish and Wildlife Service.The only birds rehabilitators can admit without a federal permit are common birds considered to be introduced invasive species