. Bulletin - United States National Museum. Science. Figure 3. Probable evolutionary dispersals of Chrysococcyx: 1. dispersal, from Malaysian area to Australia and New Zealand, facilitating the differentiation of lucidus, basalis, ruficollis, and osculans; 2. secondary movement, to New Guinea with the development of meyerii; 3. third dispersal, to southern Asia with the development of maculatus and xanthorhynchus; 4. fourth dispersal, to Africa with the differentiation of flavigularis, klaas, cupreus, and caprius. Migratory behavior In an evolutionary study such as this, migratory behavior pos
. Bulletin - United States National Museum. Science. Figure 3. Probable evolutionary dispersals of Chrysococcyx: 1. dispersal, from Malaysian area to Australia and New Zealand, facilitating the differentiation of lucidus, basalis, ruficollis, and osculans; 2. secondary movement, to New Guinea with the development of meyerii; 3. third dispersal, to southern Asia with the development of maculatus and xanthorhynchus; 4. fourth dispersal, to Africa with the differentiation of flavigularis, klaas, cupreus, and caprius. Migratory behavior In an evolutionary study such as this, migratory behavior poses two separate problems. The fii-st is the evolution of migration paths and habits within the group; the second has to do with the effects of seasonal movement on further evolution within the members of the genus. A number of authors have emphasized the role migratoriness plays in gene dispersal and have stated that it tends to reduce the chances for subspeciation by mixing up tbe populations from several breeding areas while in the common nonbreeding, "wintering" gi-ounds each year. Mayr (1963, pp. 417-418) has mentioned the high incidence of monotypic species in the migratory North American warblers, Pa- rulidae, as a case in point. He has also noted that the equally migratory buntings, Emberizidae, on the other hand, show great geographic—or racial—variability, but suggested that this may be due to the fact that they are ground-living birds, perhaps more critically exposed to selective pressures by predators and by microclimates than are the largely arboreal Parulids. The glossy cuckoos are largely arboreal, but they do not present a clear correlation of monotypy with migratoriness or, on the other hand, of pol3^typy with sedentariness. Thus, three species {ruficollis, meyerii, and flavigularis) are monotypic and non- migratory; four others (basalis, osculans, maculatus, and caprius) are monotypic and migratory; the most higlily polytypic species (mal- 267-562
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