Quote:
The names of the small Galliformes are often used interchangeable (even grouse are also sometimes called partridge) and seem to vary geographically.
Time too get technical about it!! All Old World Quail belong to the same family as Partridges (& Francolin, Pheasants),
Phasianidae. Old World Quail and Partridge belong to the same subfamily,
Perdicinae; the Old World Quail (Coturnix, Button, Rain, etc) appear as miniature versions of the larger Partridge, sharing many of the same features. The New World Quail belong to the family
Odontophoridae, this family is also known as the toothed-quails - named for their semi-hooked beak (Old World Quail have slender beaks). Some of the species in South America, as well as the Mountain Quail in North America, are naturally quite large, close in size to some of the Partridges seen in the Old World.
To sum it up and hope to not sound condescending to anyone, the use of the names interchangeably seem to be done by those who have less knowledge of biology. Think of those who see herons on a pond and call them cranes, coyotes called wolves, etc.
To see some of the species, visit
http://www.gbwf.org/quail/index.html &
http://www.gbwf.org/francolin/index.html
I also recommend Paul Johnsgard's The Quails, Partridges, and Francolins of the World
Dan