NO. 4 AVIAN GENUS CLAMATOR — FRIEDMANN 27 



The importance of settling the question as to whether glandarius 

 was originally sub-Saharan in range and later spread to the Mediter- 

 ranean areas, or vice-versa, warrants a little further discussion. Voous 

 (1960, p. 154), the only proponent of an African origin for the 

 species, considered the hypothesis for such an origin ". . . supported 

 by the occurrence of at least three other species of the genus Clamator 

 in Africa . . ." This is incorrect as there are only two, jacobinus and 

 levaillantii, while in Asia there are also two, jacobinus and coroman- 

 dus. The last named is the species to which glandarius is most clearly 

 related and appears to be the stock from which it arose. During a 

 visit to Los Angeles in 1962, Stresemann, who has been studying very 

 carefully the distributional history of the birds of Europe, agreed 

 with me in considering the sub-Saharan range of glandarius as a 

 recent expansion from an older circum-Mediterranean one. 



In this connection we may recall, in Dobzhansky's (1940, pp. 312- 

 321) words, that ". . . each species, genus and probably each geo- 

 graphical race is an adaptive complex which fits into an ecological 

 niche somewhat distinct from those occupied by other species, genera, 

 and races. The adaptive value of such a complex is determined not 

 by a single or a few genes, but is a property of the genotype as a 

 whole. Furthermore, the adaptive complex is attuned to its environ- 

 ment only so long as its historically evolved pattern remains, within 

 limits, intact . . ." Clamator glandarius is highly adapted to the 

 magpie, but yet part of its population has been able to abandon this 

 evolved situation and to become attached to as different a host relation- 

 ship as that with Spreo bicolor in South Africa. 



One cannot help but wonder if this exodus of part of the Mediter- 

 ranean glandarius may have been influenced, if not caused, by intra- 

 specific competition in a too populous stock of the species, after its 

 adaptive evolution had seemingly expedited its existence. Haldane 

 (1932, p. 119) pointed out that there is a fallacy in the concept that 

 "... natural selection will always make an organism fitter in its 

 struggle with the environment. This is clearly true when we consider 

 the members of a rare and scattered species. It is only engaged in 

 competing with other species, and in defending itself against in- 

 organic nature. But as soon as a species becomes fairly dense matters 

 are entirely different. Its members inevitably begin to compete with 

 one another . . ." 



Inasmuch as the other three species of Clamator parasitize almost 

 exclusively birds that build open, "saucer-shaped" nests, it may be 

 assumed that a similar host choice is, or originally was, basic in 

 glandarius as well, and that the use of hole-nesting starlings is a 



