The trogons and quetzals are birds in the order Trogoniformes which contains only one family, the Trogonidae. The family contains 39 species in seven genera. The fossil record of the trogons dates back 49 million years to the Early Eocene. They might constitute a member of the basal radiation of the order Coraciiformes or be closely related to mousebirds and owls. The word "trogon" is Greek for "nibbling" and refers to the fact that these birds gnaw holes in trees to make their nests.