BIRDS OF ETHIOPIA AND KENYA COLONY 105 



Juvenal plumage is alike in the two sexes. A series of 15 adult 

 females examined show great variation, chiefly with regard to the 

 number, size, and intensity of the spots on the breast and upper 

 part of the abdomen. Van Someren ^^ writes that this variation 

 appears not to be due to season, but possibly to age. 



Two breeding females are very heavily spotted on the breast and upper 

 abdomen, while another is apparently assuming male plumage [italics mine]. 

 Others, again, have the breast heavily washed with olive-grey, others are 

 almost uniform brownish. 



From the spotted condition of the young, it would seem that the 

 least spotted, most uniformly colored birds would be the oldest, and 

 vice-versa, provided that age is in any waj^ correlated with the 

 variation. 



The plumage of the male presents some points of interest. One 

 bird (from Tertale, U.S.N.M. No. 243340) still in the process of ac- 

 quiring adult plumage has the entire chin and throat white, with no 

 black patch at all. It still has a line of light, immature feathers 

 in the middle of the lower breast and upper abdomen, surrounded on 

 either side by the black and reddish feathers of the incoming plum- 

 age. Another specimen (also from Tertale, U.S.N.M. 243339) is in 

 similar plumage but the entire throat and chin are practically bare, 

 the sheaths of the new feathers just protruding from the skin. How- 

 ever, those in the area destined to become the black patch are black, 

 while those to either side of it are white. Doctor Van Someren ^^ 

 writes that buff stripes on the feathers of the underside of males are 

 a sign of immaturity. The white-throated bird has white, not buff, 

 stripes on a few of the flank feathers. 



In full adult plumage the black anchor mark on the throat varies 

 in its median, posterior extent. In some the broad middle part ex- 

 tends considerably beyond its junction with the two lateral " arms " 

 of the anchor; in others these arms seem to be one continuous band 

 posteriorly delimiting the throat patch. In some individuals the 

 white sub-ocular stripe is posteriorly continuous with the white of 

 the throat; in others it is cut off entirely by the black jugular stripes. 



This species does not vary geographically to any appreciable ex- 

 tent in the African Continent and consequently no mainland races 

 have been differentiated. Sclater and Mackworth-Praed *° were un- 

 able to separate Sudanese from South African examples. The series 

 collected in Ethiopia and extreme northern Kenya Colony by Mearns 

 average slightly larger than a series from the rest of Kenya Colony 

 and Tanganyika Territory, but the differences are small. The wing 

 lengths in Abyssinian birds vary from 96-101 (males) ; 94-102 



28 Nov. Zool., vol. 29, 3922, p. 32. 



38 Idem, p. 32. 



« Ibis, 1920, p. 841. 



