AVIAN GENUS CHRYSOCOCCYX 89 



the time between the two acts would make it uncertain that there 

 was any real connection between them. 



In the case of C. Haas in Uganda, Pitman (in lift.) considered egg 

 removal the usual, normal procedure in all nests parasitized, and he 

 wTote me that such removal was performed only by the male cuckoos. 

 Unfortunately it is not clear on what observational evidence he 

 based this statement, and one can only await the publication of his 

 work to see what actual data he may have had. In my earlier account 

 (1949a, p. 137) I attempted to summarize what was then known by 

 saying that: Klaas' cuckoo often removes an egg from the nest when 

 depositing its own, but whether it does so regularly or not remains to 

 be established. Several observers have seen one of these cuckoos with 

 an egg in its bill and have seen it break the shell and swallow the 

 contents. Captain Pitman also 'svrote me that he considered the re- 

 moval of one or more eggs from the nest by the adult male was also 

 characteristic of the dichic, C. caprius. 



In some species there is inferential evidence pointing to egg removal 

 by adult cuckoos, based on the fact that in parasitized nests the 

 number of the host's eggs is often reduced from the normal clutch 

 size by the number of cuckoo eggs laid in it. This is true for instances 

 of parasitism recorded for the species osculans, malayanus, lucidus, 

 basalis, maculatus, xanthorhynchus, Haas, cwpreus, and caprius. As an 

 example, dealing in this instance with caprius, we may cite the work 

 of Hunter (1961, pp. 55-63), who studied the masked weaver, Ploceus 

 velatus, 12 of whose nests he found to be parasitized. In none of these 

 were there more than two eggs of the host in addition to that of the 

 cuckoo (in nonparasitized nests three eggs comprised the usual clutch), 

 an indication that the cuckoo parasite regularly removed at least one 

 of the host eggs from nests into which it deposited its own. 



That host-egg removal is not invariably the case even in a species 

 as weU kno\vn (relatively) as caprius is indicated by an observation 

 sent me hj Neuby-Varty from Southern Rhodesia. He found a nest of 

 a tawny-flanked longtail, Prinia subflava affinis, with four eggs of the 

 Prinia and one of the didric cuckoo. Since in hundreds of nests of this 

 warbler Neuby-Varty had never found more than four eggs, he con- 

 cluded that the cuckoo had not removed any warbler eggs in this 

 instance. 



As a further instance of lack of egg removal by the adult parasite, 

 we may cite Reed's observations (1953, pp. 138-140). He studied the 

 didric 's parasitism on the red bishop, Euplectes orix, and reported 

 that the cuckoo does not usually remove an egg of the host, "the 

 normal Red Bishop clutch [being] three eggs, and nearly all nests 

 containing cuckoo eggs [carrying] a total of four eggs . . . ." 



However, the bulk of the observations on caprius suggest that egg 



