4 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 124 



as hosts (two species, one with a single record, the other with two) 

 but the wagtails (Motacilla) are among the regular fosterers of the 

 parasite (with 10 records for one species and 8 for the other). Of 

 bulbuls (family Pycnonotidae) five species have been found to be 

 parasitized 10 times; but only one of these, the common Pycnonotus 

 barbatus, is known to be a frequent host (six records). 



The other groups of hosts apparently are seldom bothered by the 

 red-chested cuckoo, and it seems safe to conclude that these hosts 

 play no important role in the cuckoo's economy and that, conversely, 

 its effect on them is very slight. These groups include the flycatchers, 

 tits, sunbirds, weavers, shrikes, and finches. 



If we attempt to estimate the relative frequency of host selection 

 by the red-chested cuckoo, our present data reveals the following 

 sequence: By far the most frequently imposed upon host is Cossypha 

 cajfra with 35 records, followed by C. heuglini with 11, Motacilla 

 capensis with 10, M. alba and Saxicola torquata with 8 each, C. semiruja 

 with 7, Monticola rupestris and Pycnonotus barbatus with 6 each, 

 while all the other hosts are known as yet only from single or, at 

 most, two instances apiece. 



It seems evident that unusually small hosts, such as Remiz minutus 

 and Nectarinia famosa, are probably unusual reports in the same sense 

 as the "freak" host records for the cuckoo (C. canorus) in Europe or 

 the brown-headed cowbird (Molothrus ater) in North America. There 

 are but single records for R. minutus and N. famosa, and it may be 

 recalled that the record for the former is an old Levaillant one, un- 

 supported by more recent evidence, that is open to doubt as I pointed 

 out in an earlier publication (1949a, p. 77). The lone instance involving 

 the malachite sunbird, however, is clearly acceptable as it was re- 

 corded by a very careful and reliable observer in Natal, Godfrey 

 Symons. 



All the known hosts are passerine birds and all are birds that make 

 open nests. These cuckoos "have been said to show interest" in some 

 of the domed or globular nests of weavers, but I know of no records 

 of their depositing eggs in them. The absence of babblers from the 

 list is of interest as it leaves these birds to the attention of the crested 

 cuckoos, Clamator, with which the red-chested cuckoo does not seem 

 to conflict seriously. 



Not only do we now have a fairly good picture of the range of host 

 selection of this cuckoo, but also we now have to revise our earlier 

 conclusions about its egg morphism. When I first wrote of this matter 

 (1949a, pp. 68-69), I could only state that the eggs showed very 

 little variation when compared with those of the well-known common 

 cuckoo of Europe. The majority of all the then-known eggs of the 

 red-chested cuckoo were plain, unmarked chocolate brown to olive 



