NO. 4 AVIAN GENUS CLAMATOR — FRIEDMANN 3I 



cannot easily accept its apparent unimportance here. At least part 

 of the answer to this puzzle lies in the fact that because these two 

 cuckoos were studied earlier in India and in the Mediterranean lands 

 than in sub-Saharan Africa we have come to accept the adaptive 

 excellence reported for them from those areas as an essential and 

 necessary aspect of their natural economy. But now we know that, 

 advantageous as this may be, it is not essential, and that the two 

 species can and do survive without it. Actually, this is implied even 

 in the course of the evolution of the climax adaptation in the areas 

 where it has transpired, as countless less completely adapted gen- 

 erations had to survive to provide the material out of which was 

 achieved the greater perfection, which in time supplanted the less 

 adapted birds. 



We have, then, a superficially similar situation in southern Africa 

 in both the great-spotted and the jacobin cuckoos, but one which 

 appears, on more careful study, to be due to opposite evolutionary 

 trends. In the jacobin it seems probable that the southern popula- 

 tion, serratus, is the original, primitive segment of the species that 

 has remained as it was while giving rise to the more advanced pica 

 and jacohinus, an evolution involving primarily the change from un- 

 pigmented to pigmented eggshell. On the other hand, the fact that 

 in sub-Saharan Africa glandarhis is not only bereft of the adaptive 

 advantage its egg evolution had given it in Mediterranean lands, but 

 further that in its southern range there is a striking difference in 

 the numerical relationship of parasite-host eggs in parasitized nests 

 in the two areas causes the southern population of this species to 

 seem relatively so inept that it may only be explained on the basis 

 of the recency of its invasion into that area. 



What has happened with C. glandarius is paralleled by a similar, 

 though less extensive, move in the jacobin cuckoo. Although 

 the geographic spread of C. jacohinus from Africa to India is 

 something that happened relatively early in its evolutionary his- 

 tory, the species has expanded its range in India more recently by 

 advancing higher into the hills. Thus, Baker (1942, p. 83) con- 

 sidered it possible that its present breeding in the hills up to 6,000 

 feet and even higher in Assam and in the central Himalayas was a 

 "modern extension of its breeding habitat. In the Plains ... its normal 

 fosterer, or group of fosterers is so completely estabHshed that excep- 

 tions are very, very few. In the lower hills the Cuckoo adheres 

 closely to the Necklaced and the Striated Laughing-Thrushes, but 

 above the normal elevation of the breeding areas of these birds or 



