Taxonomy of the Buttonquail
"In the major order of the Cranes there is no group that has confounded the researchers regarding taxonomy as much as the Buttonquail (Order Turnicidae). It seems as if these are pushing for promotion towards another order or even towards a separate order of their own. Regarding size, appearance and behaviour theymostly resemble the quail, which belongs to the order of the Galliformes (poultry)".
Before 1990 science had a huge problem classifying the buttonquail, as Erich Thenius explains in 1969 in Grzimek's "The Life of Animals", Volume VIII, Birds, Part 2". He detects Crane- as well as Poultry characteristics (note that the common quail belongs to the order of the poultry, family of pheasants).
Regarding size, look and motion the buttonquails resemble mostly quails, which belong to the order containing the poultry. They also distinguish themselves from the order of the Cranes with additional quail-like properties:
The buttonquail also shows properties that are more befitting to members of the order of the cranes:
Thet they do not have a crop is rather surprising, as these birds feed themselves, amongst others, with all kinds of seeds.
Some properties are common with neither poultry or cranes:
Erich Thenius concludes: "Considering all these properties the buttonquails are a sister order of all cranes, waders and gulls, making them a separate order, or they take a specific separate position within the order of the cranes next to all other groups of cranes, rails and bustards.
Although the buttonquail were, as indicated above, traditionally assigned to the gruiformes or galliformes (respectively the crane- or poultry-orders), they did obtain in the Sibley-Ahlquist taxonomy a proper class in the eighties: the turniciformes. New molecular-genetic research done in the nineties assigns them to the order of the charadriiformes (the waders).