Taxonomy
The Pteroclididae was formerly included in the Galliformes due to the similarities the family shares with the true grouse. However, it was later discovered that these similarities are superficial and a result of convergent evolution. Sandgrouse were later placed near the Columbiformes largely due to their reported ability to drink by the "sucking" or "pumping" action of peristalsis of the esophagus. The only other group, however, which shows the same behavior, the Pteroclidae, is placed near the doves just by this doubtless very old characteristic. More recently, it has been reported that they cannot suck up water in this way, and they are now treated separately in the order Pteroclidiformes. They have been considered near passerine birds and are considered by some to be closer to the shorebirds.
In the DNA-study by Fain and Houde (2004) they were included in the Metaves, together with the Columbiformes. In the larger study by Hackett et al. (2008) they were once again positioned close to the Columbiformes but also the Mesites. The intricately patterned, precocial downy young and egg colouration (though not shape) closely resemble those of many Charadriiformes. Eggs are near elliptical.
Read more about this topic: Sandgrouse