From the smallest, the elf owl, to the largest, the great gray owl, here is information about the 21 types that are believed to be living in North America. From egg to owlet to fierce bird of prey, here is an insightful look at these impressive creatures of the night.From the smallest, the elf owl, to the largest, the great gray owl, here is information about the 21 types that are believed to be living in North America. From egg to owlet to fierce bird of prey, here is an insightful look at these impressive creatures of the night.