It is not common knowledge that birds scratch themselves in two different ways. There's the direct scratchers, which just raise their leg under their wing and scratch away, and the indirect scratchers, which lift their leg over their wing to scratch. American Robins, as this image shows, are Indirect Scratchers- note the leg over the top of the wing. In fact all the Passerine (the perching song birds) families are Indirect Scratchers, except one, the Babblers. The way birds scratch has taxonomic significance and at least within families, they do it only one way. If a species in a family scratches the "wrong" way it is strong evidence that it belongs in another family.
Hey Ann- "Babblers" are an Old World family of birds. You know I never thought about the name until now! I guess that comes from more than 50 years of immersion in birds. The scientific name of the family is Timaliidae. It's a very diverse group. The Wrentit of North America was once thought to be a babbler but that one has been re-thought. Also the Bearded Reedling or Bearded Tit was once thought to be a babbler but is now in its own family.