the honey-guides 135 



Eggs and Egg Laying 



The eggs of the greater honey-guide are pure white, quite glossy, 

 oval in shape (i. e., there is relatively little difference between the 

 "small" and the "large" poles), and vary in size from 22.7-26 by 

 16.8-19.6 mm., the largest one 26 by 19.6 mm., the smallest one 22.8 by 

 16.8 mm. The eggs of this species are not always certainly distin- 

 guishable from those of Indicator variegatus and /. minor, and differ 

 from them only in being usually larger. It would be difficult if not 

 impossible to separate with any certainty a small egg of /. indicator 

 from a large one of /. minor or I. variegatus, as the maximal measure- 

 ments of /. minor eggs are almost as large (22.5 by 17.9 mm.) as the 

 minimal ones for /. indicator. 



As far as I know no one has ever taken a fully shelled egg from the 

 oviduct of a shot female, so, in a sense, there are no absolutely authen- 

 tic eggs of the greater honey-guide in any collection. The eggs are 

 definitely known, however, from descriptions of examples that were 

 allowed to hatch and were subsequently identified by the chicks when 

 they acquired their juvenile plumage. The impossibility of identifying 

 the egg, as such, in museum collections enters all too often into our 

 discussion of the various host records given below. In many cases, 

 however, the eggs were collected by experienced field workers who 

 knew the local fauna well and were satisfied that Indicator variegatus 

 did not occur in the localities mvolved. To reject their identifications 

 of the eggs as /. indicator in all cases would call for needlessly rigid 

 standards. It remains true, nevertheless, that in many of these cases 

 the identification is arrived at by elimination rather than b}^ more 

 positive and direct methods. It would be well, to settle all doubts 

 and to satisfy aU scruples, if someone were to collect an oviduct egg 

 as a positive reference specunen. 



Inasmuch as the eggs of honey-guides and those of then nearest 

 relatives — the barbets, woodpeckers, etc. — are always pure white, and 

 inasmuch as the bulk of their victims belong to the white-egg-laying 

 piciform and coraciiform families, it is not possible to look upon this 

 as a case of adaptive egg similarity between parasite and victim. 

 While most of the victims are birds that lay white eggs, there are 

 others that do not. Among the latter group may be mentioned 

 Phoeniculus purpureus, Rhinopomastus cyanomelas, Hirundo albigu- 

 laris, Monticola rupestris, Cinnyricinclus leucogaster, and Spreo hicolor. 

 The last named is certainly a frequently victimized species. It may 

 be argued that as most of these birds nest in the darkness of long 

 tunnels, or at least in the dense shade of ledges, color adaptation in 

 eggs may not have been of selective value in the history of the honey- 



