Columbiformes

Columbiformes are an avian order that includes the very widespread and successful doves and pigeons, classified in the family Columbidae, and the extinct Dodo and the Rodrigues Solitaire, long classified as a second family Raphidae. 313 species, found worldwide, comprise the Columbiformes order. Like many birds, all Columbiformes are monogamous. Unlike most other birds, however, they are capable of drinking by sucking up water, without needing to tilt the head back.

Taxonomy
The Pteroclidae (sandgrouse) were formerly included in this order largely due to this drinking behavior ("The only other group, however, which shows the same behavior, the Pteroclidae, is placed near the doves just by this doubtlessly very old characteristic." ); more recently, it had been reported that they cannot drink by "sucking" or "pumping", and they are now treated separately in the order Pteroclidiformes and are considered to be closer to the shorebirds.

Osteology and DNA sequence analyses indicate that the Dodo and Rodrigues Solitaire are better considered as a subfamily Raphinae in the Columbidae pending availability of further information.