NO. 4 AVIAN GENUS CLAMATOR — FRIEDMANN 3 



haviour of the cuckoo, the instincts of the cuckoo, are determined by 

 its heredity. Its migration and all its malpractices follow the pattern 

 of a parent it has never seen. 



"Further, of all animals, the female cuckoo most resembles man in 

 exercising a choice which fixes her offsprings' environment . . . the 

 cuckoo species is divided into mating groups which specialize in 

 laying eggs in the nests of birds whose eggs theirs most closely 

 resemble. The cuckoo species, like any large human community, thus 

 has a spurious plasticity which derives from its variability. This 

 variability, again like that of a human community, is preserved by 

 natural selection, that is, by the adaptive value of a whole range of 

 genetic types. The cuckoo is thus the most significant of all birds for 

 the theory of heredity and environment . . ." 



Without detracting from Darlington's estimate of the inherent 

 philosophical importance of the biology of Cnculiis canoriis, it may be 

 suggested that the present account of a group of that bird's less 

 completely specialized relatives may even enhance it by presenting 

 informative perspectives and tangential views into our total concept 

 of brood parasitism in this family. There is a real need for this, 

 since, in spite of the known differences in the mode of parasitism in 

 the various genera of parasitic cuckoos, the literature of the subject 

 is devoted largely to that one species, which, it so happens, is the 

 most highly evolved and specialized of all the members of its family 

 and possesses many features not present in other parasitic cuckoos. 

 This has resulted in an overly accented, rather one-sided emphasis in 

 the usual presentations and discussions of the subject. It is hoped 

 that the present study may help to correct this and to offset some 

 of the literature on cuckoo parasitism. 



At the same time, the situation present in the four species of 

 Clamator is, in itself, well worthy of study as a survey of the evolu- 

 tionary history of a compact and relatively isolated genus of the 

 family, only distantly related to Cuculus. The genus Clamator gen- 

 erally is considered fairly primitive; however, its included species 

 reveal much adaptive evolution and the effects of diverse and not 

 altogether harmonious trends. Not only is it a primitive group of 

 highly specialized species but also one that reveals to a greater de- 

 gree than most that evolution may proceed at different rates in 

 different characters and in different species even within a small genus, 

 and that some of these trends may even be abandoned after a state 

 of high perfection had been achieved. In these respects this study 

 differs from most. 



