BIRDS OF ETHIOPIA AND KENYA COLONY 467 



Female adult, between Thika and Athi Rivers, Kenya Colony, 

 August 29, 1912. 



Soft parts : Male adult ; bare skin around eye neutral tint ; iris 

 bro^yn ; bill all purplish flesh color ; feet plumbeous ; claws black. 



As is now well known, the yellow-throated birds (described as /. 

 majo?') are the immature of the present species. I have examined 

 a series of 50 specimens of this honey guide from South Africa, 

 Tanganyika Territory, Kenya Colony, Belgian Congo, the Sudan, 

 and Ethiopia and conclude (as others have done before) that no 

 geographic races are recognizable. The birds vary considerably in 

 size, but the variations are purely individual. Males are larger than 

 females; wings 110-117 in the males, 96-108 millimeters in the 

 females; tail 70-76.5 as against 62-68 millimeters; culmen 13-15.5 

 as against 11-13 millimeters. 



The four immature birds are in the middle of the postjuvenal 

 molt. The two males present a rather bizarre appearance with their 

 black and yellowish-white checkerboard throats. The postjuvenal 

 molt is incomplete, as it does not affect the remiges and rectrices. 

 The margins of the old upper wing coverts, scapulars, and inter- 

 scapulars become extremely faded by the time the postjuvenal molt 

 begins, being much tawnier, more sandy, less olivaceous than when 

 fresh. The molt appears to begin rather irregularly in the scapular 

 and interscapular tracts, then starts on the chin and throat and the 

 upper wing and tail coverts. The juvenal median upper tail coverts 

 have not dusky shaft stripes and may thereby be distinguished from 

 the adult feathers. These feathers are all replaced and full grown 

 long before the upper wing coverts are through with the molting 

 process. The last parts to molt are the forehead and crown. 



The first adult plumage is worn but a short time when the old 

 (juvenal) remiges and rectrices are replaced. The wing molt slightly 

 antecedes the caudal ecdysis and appears to have but one center of 

 origin, the carpal joint. 



It is decidedly unusual to find a bird in which the juvenal plum- 

 age is so totally different from that of the parents of either sex, and 

 this a plumage which is in no way indicative of any phylogenetic 

 significance. It is little wonder that the yellow-breasted birds were 

 long considered a distinct species. 



Mearns recorded the note of this honey guide as toeak-tea, weak- 

 tea. Besides the specimens procured, he observed the species as fol- 

 lows: South of Lake Abaya, March 26-29, 1 bird; Gato Eiver near 

 Gardula, March 29 to May 17, 20 seen ; Anole Village, Sagon River, 

 and Bodessa, May 19 to June 3, 4 noted ; Tana River, August 15, 1 ; 

 Tana River at mouth of Thika River, August 23-26, 4 seen; Thika 

 River, August 27, 10 birds; west of the Ithanga Hills, August 28, 



94312—30 31 



