 Altogether, the "genus" seems more like an assemblage of species brought together largely by seeming even less close to other groups than to each other, rather than by a very close relationship.More extreme cases of adaptive radiation exist in birds, but this process hardly ever occurs outside island groups like Hawaiian honeycreepers, vangas, Malagasy warblers or the famous Galápagos finches.The latest comprehensive analysis of the genus was a 1977 study which today would not be accepted whole-cloth because it followed the phenetic methodology then in vogue but now considered outdated.