AVIAN GENUS CHRYSOCOCCYX 65 



Ottow and Duve (1965) presented a summary and interpretation 

 of Duve's observations, pointing out that, although the red bishops 

 were parasitized very heavily (52 instances in the one small area), 

 other species of birds nesting nearby and known to be parasitized by 

 didrics in other localities (Prinia, two species of Ploceus, etc.) were 

 never bothered by the cuckoos. This suggests that the local didric 

 hens were rigidly fixed, or specific, on Euplectes orix. It was concluded 

 (p. 432) that each female caprius was restricted to a single host 

 species. That such host specificity is pui'ely an individual matter is 

 supported by the fact that in other areas where both the didric 

 cuckoos and the red bishops are breeding the latter are not parasitized. 

 Thus, in the eastern Cape Province, Skead (1956, p. 125) reported 

 that his colony of red bishops was never parasitized, although adult 

 didrics were seen from time to time in the vicinity. Skead noted 

 Reed's 16 records of parasitism on this bird from near Johannesbiu-g 

 and emphasized the fact that his local cuckoos were not Euplectes 

 parasites. 



Many years earlier I reported (Friedman, 1928, p. 37) that in the 

 northern Transvaal I had found in several instances didric cuckoos 

 appeared to have established "territories" around trees containing 

 colonies of masked weavers, Ploceus velaius, and that in four cases 

 their territories seemed restricted to single trees in an area where the 

 trees inhabited by the weavers were fau-ly mdely separated — about 

 a quarter of a mile apart. These colonies contained but a single 

 species of weaver, from which it would follow that the parasite by 

 restricting its attentions to the colony in effect would be host specific. 

 In two of these colonies where a didric cuckoo was seen day after 

 day and at different times of the day I cut down and examined every 

 nest. "In the first case there were 37 nests; of these 20 were in use and 

 of these 4 contained a single egg apiece of the didric cuckoo. The 

 eggs were so similar as to indicate that aU were the product of the 

 same female. In the second case there were 28 nests; of these 18 were 

 in use and of these 3 contained an egg of the didric apiece, again 

 apparently the product of one individual" (Friedmann, 1949a, p. 172). 



Near Bloemhof, Transvaal, Plowes (1946a, p. 142) found three 

 white eggs of the didric in as many nests of tJie masked weaver. That 

 he considered them aU the product of one hen is indicated in his 

 conclusion that this cuckoo lays at least three eggs, "as I found that 

 number of white eggs in one Masked Weaver colony. . . ." Onefui'ther 

 instance of host specificity is that reported by Serle (1950, p. 356) 

 from British Cameroons. In a colony of black weavers, Ploceus 

 nigerrimus, four nests were parasitized by the didric cuckoo. The 

 four didric eggs involved were very similar, suggesting that they had 



