Classification As originally defined, the Coraciiforme order did not respect monophyly (i.e., property of a clade comprising all descendants of a common ancestor and only these), since phylogenomic analysis showed that the Piciforme order would be lying in it. Monophyly was restored by recognizing Bucerotiformes, Piciformes and the remaining Coraciiformes as separate orders. Coraciiformes were restricted to the families illustrated at right, plus two families not shown, Brachiipteraciidae (ground rollers) and Todidae (todies).

Coraciiformes have been described as a fairly large order characterized anatomically by syndactyl feet (three forward pointing toes), long, pointed bills and rich colors. They are monogamous and nest in cavities. Their young are altricial (requiring care by parents) and retain waxy sheaths on their feathers until just before fledging. Most birds of this order are carnivorous.

Coraciidae (Rollers) Sitting on exposed perches, rollers will seize on the ground all kinds of small animals, including scorpions and lizzards, little snakes, toads, and rodents. Anatomically, they differ from all other coraciiforms by having two inner toes connected while the outer toe moves freely.

Alcedinidae (Kingfishers) are divided into three subfamilies on the basis of genomic studies. The Alcedininae (small blue and rufous species) and Cerylinae (green and giant ones), are the fishing kingfishers, watching their prey from a perch or hovering above water before diving. The Daceloninae, also called Halcyonidae, are not primarily fish eaters, hunting for small animals in tropical rain forests or open woodlands.

Momotidae (Motmots) are recognized, at least in the six largest species, by the long tail whose central feathers are  greatly elongated and racked–tipped. The birds wag their tail from side to side. They catch insects in flight.

Meropidae (Bee-eaters) are arboreal, graceful birds that catch a variety of insects in flights, but mostly bees and wasps, as well as locusts.

Hackett SJ et al (2008): Phylogenomic Study of Birds

http://fr.wikipedia.org/wiki/Coraciiformes

Fry CH and Fry K (1999): Kingfishers, Bea-eaters & Rollers, Princeton University Press, Princeton, NJ.

Austin O.L. Jr, Singer A. (1961): Birds of the World, Golden Press, New York, p 175-179.