20 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL, I46 



One important point, not revealed by the tabulation, is the relative 

 frequency with which the different hosts are selected. Out of the 

 total 123 African records, 59 are of species of the genus Pycnonotus, 

 and 14 more are of other bulbuls, making a total of 7Z, or almost 60 

 percent of the total, that refer to this one family of hosts ; 23 are 

 of one species of Lanius, and 10 more are of other shrikes, a total 

 for this family of 33, or more than 25 percent of the total ; only 5, 

 or not quite 5 percent, are of babblers. On the other hand, out of 

 106 Asiatic records, only 1 is of a Pycnonotus, but over 85 percent 

 are of babblers, chiefly of the genera Turdoides and Garrulax. 



The figures given above for the frequency of parasitism on bulbuls 

 and shrikes in Africa are actually below the truth, as they are based 

 solely on the total of individual instances reported. They make no 

 allowance for the undocumented, general statements of experienced 

 collectors, such as Plowes (1944, p. 93), who wrote that practically 

 every bulbul nest examined was found to contain one or more eggs 

 of the jacobin cuckoo. Also, generally a lower percentage of cases of 

 parasitism on frequent hosts gets into the literature because of their 

 repetitive nature, whereas practically all cases of infrequent ones are 

 apt to find their way into print eventually. 



As may be seen from the list of fosterers, in the great majority of 

 cases the pied crested cuckoo lays its eggs in open, cup-shaped nests 

 built in trees or bushes. The one record of its using a kingfisher as 

 a host ( Schonwetter, 1928, p. 130) and the two involving the rock 

 sparrow, Petronia (de Klerk, 1942, p. 58), are the only instances of 

 its parasitizing hole-nesting species. Another unusual type of nest 

 choice is the lone case of a coucal, Centropus grillii zvahlbergi, as a 

 host. This bird builds a roofed-over, or domed, nest of fine twigs and 

 grasses, on the ground. Other frequently terrestrial-located nests 

 known to be used occasionally are those of two species of wagtails, 

 Motacilla capensis capensis and Motacilla aguimp vidua, and of the 

 grass-bird, Sphenoeacus afer transvaalensis. 



In the present state of our knowledge of Clamator jacobinus the 

 only obvious difference in its overall "fitness" to all the aspects of 

 its existence in India and northeastern Africa on the one hand, and 

 in southern Africa, on the other, is the much lesser degree of adaptive 

 similarity of its eggs to those of its common hosts in the latter area. 

 Strangely enough, in the areas where there is adaptive similarity it 

 appears to have value to the parasite, but in the areas where it is 



