26 U.S. NATIONAL MUSEUM BULLETIN 2 65 



ayanus) is nonmigratory; one (lucidus) is polytypic -with two of its 

 four races migratory and two sedentary; two others (Haas &nd cupreus) 

 are partly migratory and slightly polytypic; the remaining one 

 (xanthorhynchus) is polytypic, but its migratoriness, although not yet 

 known, seems slight and partial. 



In the tropics migration of more than very local movement is 

 indulged in by relatively fewer kinds of small land birds than is the 

 case in the temperate areas. Cuckoos, as a family, are among the most 

 migratory of land birds, and in the glossy cuckoos, which are primarily 

 tropical in their distribution (although extending into southern, sub- 

 tropical areas or even south-temperate regions in New Zealand, 

 southern Australia, Tasmania, and southern Africa), we find every 

 conceivable degree of migratory behavior, from none at all to some 

 of the most outstanding geographic movements known, involving 

 twice-yearly flights of more than 2000 mUes nonstop over open seas. 



Something of the degree to which migratory behavior occurs in the 

 cuckoos may be realized by a few statements culled from the literature. 

 In New Zealand Hutton (1900, p. 215) noted that the only regular 

 summer visitors (i.e., breeding visitors) to New Zealand are the two 

 parasitic cuckoos that occur there {Chrysococcyx lucidus lucidus and 

 Urodynamis iaitensis). All the other small land birds that breed in 

 those islands are completely sedentary inhabitants of their indi- 

 vidual habitats. A few years later W. L. Sclater (1906, pp. 14-21) 

 estimated that, of the 814 species of birds then known to occur in 

 southern Africa south of the Zambezi, 731 were resident and only 21 

 were considered to be African migrants, as distinguished from Eurasian 

 winter visitors. Of these 21, no fewer than 9 were cuckoos (aU 

 parasitic) . 



Aside from emphasizing that as a family cuckoos are prone to 

 migratoriness, these observations also strongly suggest that the 

 cuckoos came to these southern-subtropical and temperate areas 

 from the tropics and that they did not originate in those breeding 

 areas that they still annually desert during the nonbreeding season. 

 In other words, their present "wintering" ranges give us some sug- 

 gestive clues as to the areas from which the birds long ago extended 

 their distribution. However, it must be stated by way of caution that 

 this idea, if followed too literally, could present some difficulties that 

 cannot be explained in terms of the contemporary picture. Thus, 

 C. lucidus lucidus of New Zealand migrates to the Solomon Islands 

 for its "winter" season. If we were to assume from this that lucidus 

 was originally a Solomon Islands bird, we would have to explain why 

 neither it nor any other glossy cuckoo breeds in those islands today. 

 The climate, the vegetation, the presence of potentially suitable hosts 

 (although there are no Gerygone warblers, there are fantaOs, Rhipi- 

 dura — used as a host by C. malayanus russatus — and a number of 



