an order of birds; anatomically they are close to the Coraciiformes and the Passeriformes. They are smalland medium-sized arboreal birds, which nest in hollows or burrows. The eggs are white, and the young of most species are naked when they hatch. They vary greatly in outer appearance and habits. There are six families: Galbulidae, Bucconidae, Ramphastidae, Indicatoridae, Capitonidae, and Picidae. There are approximately 400 species, found throughout the world except for Madagascar, Australia, New Zealand, New Guinea, and Polynesia. Piciformes are most numerous in tropical forests.