AVIAN GENUS CHRYSOCOCCYX 75 



generally are fairly similar, but also from nests of Euplectes orix and of 

 Ploceus capensis olivaceus, both of whose eggs are uniformly bluish, 

 and from nests of Ploceus velatits and Ploceus xanthops jamesoni, both 

 of which species lay speckled eggs. According to Schonwetter this is 

 the most frequent type of caprius egg (10 out of 24 that he examined). 

 Near Johannesburg, R. A. Reed (m litt.) found that all caprius eggs 

 found in nests of Passer melanurus were hghter in color than those of 

 the host, Avath some tinge of blue in the whitish ground color and with 

 freckling, in every egg examined, finer and more evenly spread, al- 

 though the freckling was hea\nest around the obtuse pole of the eggs. 



Roberts (1926, pp. 232-234) described a number of didric eggs of 

 this morph, comparing them with those of the hosts in whose nests 

 they were found, reported a fair approximation between them in four 

 clutches of Passer melanurus. In other cases, however, there was little 

 or no egg similarity, as was further shown by Plowes (1945, p. 113), 

 who noted no less than four different didric egg morphs in nests of 

 Ploce us velatus alone, none of them agreeing with the eggs of the host. 

 5. Pinkish background color, with speckles and larger markings of 

 pinkish brown, and brownish gray (not Usted by Schonwetter, but 

 recorded from a nest of Ploceus velatus by R. A. Reed [in litt.]; appar- 

 ently a relatively uncommon egg morph). The egg described by 

 Markus (1961, p. 33) was merely described as light pink speckled with 

 pinkish brown; the one reported by Reed had a pinkish ground color, 

 with dark frecklings of browns and grays sparsely scattered, except 

 on the obtuse end where these markings coalesced to form a ring. 



Other, somewhat variant, egg morphs have been described, as 

 follows: cream color, finely blotched with light reddish brown and 

 underlying pale mauve; very pale gi'een with reddish-brown blotches, 

 especially near the larger pole; blue with greenish spots (Markus, 

 Priest, and others). 



Judging from the data presented above, together with further 

 notes by Hunter (1961, p. 55), Markus (1963, p. 47; 1964, p. 123), 

 Moreau (1949, pp. 535-536), Reed (1953, p. 138), and others, and 

 from the conclusions of Schonwetter (1964) it may be said that the 

 didric cuckoo shows adaptive egg resemblance in coloration to two of 

 its common hosts, Euplectes orix, and Passer melanurus, but that this 

 is by no means constant. The degree of adaptation or, perhaps more 

 accurately, the incidence of approximate resemblance is greater in 

 those individual didrics parasitic on red bishops than in those laying 

 eggs in the nests of Cape sparrows. In the case of those didrics para- 

 sitizing masked weavers there is less evidence for constant egg adapta- 

 tion. Markus (1961, p. 33) found three types of didric eggs in nests 

 of this host. Hunter (1961) studied about 120 nests of the masked 

 weaver and distinguished 10 egg morphs of this species. He found 



