BIRDS OF ETHIOPIA AND KENYA COLONY 329 



of age, as previously thought, but a seasonal one. Van Someren,'^^ 

 however, found that "the state of the wattles m no way indicates the 

 condition of the reproductive organs." Some of his birds in breeding 

 condition had the heads still covered with feathers, although wattles 

 were present. According to de Schauensee, his bird (a captive indi- 

 vidual) had the head completely bare, with the w^attles well developed, 

 in May. It remained this way until the end of October when feathers 

 began to sprout about the throat wattles. "At this point", he says, 

 "the wattles began to shrink and the feathers spread slowly back- 

 wards to the crown and occiput, and by the beginning of December 

 the head was completely feathered. The bird continued in this 

 plumage until May. The feathers of the head then began to fall out 

 and the wattles to swell and by the middle of June the head was 

 exactly as it had been the summer before." 



Van Someren kept birds in captivity for two years at Nairobi and 

 failed to jSnd any seasonal change in them, but it has been suggested 

 that molt is often irregular in equatorial regions. 



Finally, to bring the evidence to a close, it may be mentioned that 

 the United States National Museum has a completely gymnocephalic 

 male, shot on February 14, at Ledgus, on the Sudan-Uganda border, 

 which has no sign of wattles either on the throat or the crown. 



The phenomenon of gymnocephaly in Creatophora makes one want 

 to compare it with some of the honey-eaters of the Australian region, 

 such as Philemon argenticeps and Tropidorhynchus novae-guinea ; 

 with Allocotops calvus of Borneo; with its nearer relative Mino 

 dwmonti; with some of the birds of paradise, such as Paradigalla 

 carunculata and Schlegelia wilsoni; and with Plcathartes of West 

 Africa. In some notably gymnocephalic birds, such as vultures, 

 guinea-fowls, and some storks, cephalic nudity appears to be a matter 

 of age (in some storks even the nestlings have bare areas on the head, 

 however). In the Meliphagidae the condition appears in the first 

 plumage and seems not to alter with age; in the babbler Allocotops 

 gymnocephaly is said to be wholly an age character; in the Para- 

 diseidae the data are too meager to help us much ; in the glossy star- 

 lings, il/mo, Sarcops^ and Eulabes^ the bare spaces are present in the 

 young but may be slightly larger in the adults. Again, the available 

 information is not sufficient to allow a comparison with some of the 

 tropical American cotingas, such as GymnocephaJus^ Gymnoderas, 

 and ChasniorhyncJius. In the European rook, bareness comes with 

 age. 



Though the data on gymnocephaly are not even nearly satisfactory 

 as yet, it appears that, if de Schauensee's bird was acting in ,a 

 natural way, Creatophora is the only bird known to possess seasonal 

 gymnocephaly other than the ruff. Machetes pugnax. In the light of 



"Nov. Zool., vol. 29, p. 128, 1922. 



