Alpha codes, also known as banding codes or bird codes, are four-letter abbreviations for bird names used by bird banders, ornithologists, and birdwatchers in North and Central America. The codes are written in capital letters, and look like, e.g., MODO for mourning dove. There are two very similar systems of these codes currently in use, one maintained by the Bird Banding Laboratory (BBL) of the North American Bird Banding Program, and the other by the Institute for Bird Populations (IBP). The codes used by the two systems are the same for most birds, but not for all.