Determining Homology of Molts and Plumages to Address Evolutionary Questions: A Rejoinder regarding Emberizid Finches

• Published in: The Condor (Los Angeles, Calif.) Calif.), 1994-08, Vol.96 (3), p.769-782
• Main Authors: Thompson, Christopher W., Leu, Matthias
• Format: Article
• Language: English
• Subjects: Aves; Aviculture; Biological and medical sciences; Birds; Evolution; Feathers; Fundamental and applied biological sciences. Psychology; Molting; Ornithology; Passeres; Plumage; Songbirds; Sparrows; Terminology; Vertebrates: general zoology, morphology, phylogeny, systematics, cytogenetics, geographical distribution
• ISSN: 0010-5422; 1938-5129; 2732-4621
• DOI: 10.2307/1369480

Determining how molt is integrated into the annual cycle, and understanding what natural selection pressures have favored the diversity of molt strategies in birds are important issues in ornithology and zoology in general. To study these issues, most ornithologists historically have used and continue to use many different nomenclatural systems which tie names of molts and plumages (e.g., breeding plumage, summer plumage, adult plumage) to events in the annual cycle, season or age. However, it is circular to study the evolution of molts and plumages in relation to annual cycle events, seasons or age because the definitions of plumages and molts in these systems are defined in terms of these parameters. To study the evolution of molts and plumages it is essential to use a system such as that proposed by Humphrey and Parkes (1959, 1963) to identify homologous molts and plumages that is independent of annual cycle events, seasons and age. This paper discusses how to use correctly the Humphrey-Parkes system and illustrates this by discussing an example of how the Humphrey-Parkes system was applied incorrectly in a series of studies on Passerina buntings. We also document that Phainopeplas, Phainopepla nitens, Yellow-breasted Chats, Icteria virens, Northern Cardinals, Cardinalis cardinalis, and Orange-breasted Buntings, Passerina leclancherii exhibit a previously unknown sequence of molts and plumages that is homologous to that of other recently studied Passerina species, and suggest that this sequence of molts and plumages probably is much more widespread in birds than is currently recognized.