Multivariate Study of Morphological Variation in Galápagos and Ecuadorean Mockingbirds

Abstract

Compared with the remarkable and wellknown diversification of finches within the Galapagos Archipelago, the mockingbirds rate a poor second. They are almost as widely distributed as the finches but only one form is found on any island, in contrast to a maximum of nine finch species on some of the large, high islands (Bowman 1961). Like the finches, the mockingbirds have been well collected. This study is based on measurements made on 1,100 sexed museum specimens. However, unlike the finches, mockingbirds have never been subjected to proper morphometric study; previous woirkers have worked only on limited collectioijs. Darwin made the Galapagos mockingbirds known to science when he collected five specimens. These were described by Gould (1837), who placed them in the genus Orpheus. Ridgway (1890) proposed the new genus Nesomimus (restricted to the Galapagos) and placed all mainland forms in the genus Mimus. However, we prefer to treat the Gal/apagos mockingbirds as congeneric within mainland mockingbirds (Rothschild and Hartert 1899, Bowman and Carter 1971) . It is generally agreed that the Ecuadorean populations belong to the species M. longicaudatus. In contrast, there have been considerable differences in the taxonomic treat-