70 
Mr. J. H. Gurney's Notes on 
coverts, especially tlie latter, exhibit a considerably larger 
proportion of fuliginous markings, and a proportionately 
smaller admixture of fulvous spots, than are to be found in 
the young of B. erythronotus, in contrast with which there is, 
however, in the young of B. poliosomus , a conspicuous nuchal 
patch of pale luteous, varied by dark brown shaft-marks in 
the centre of each feather. 
On the under surface the young B. poliosomus is by far the 
darker bird of the two, except as regards the throat, which is 
of an equally deep brown in both species. In the first plu¬ 
mage of B. poliosomus the entire colouring of the underparts 
of the body is dark fuliginous brown, with the exception of 
narrow fulvous edgings to the feathers on the throat, of some 
small fulvous spots on the sides of the breast and abdomen, 
and of similar but larger spots on the thighs and under tail- 
coverts. The tail is alike in both species. 
The specimen described by Mr. Sharpe as a “ female (? in 
changing plumage) ” appears from its dimensions to be more 
probably a male not fully adult *; and this circumstance, com¬ 
bined with the fact that a very nearly adult male from Chili 
(in the Norwich Museum) still retains slight rufous tips to 
some of the feathers on the sides of the neck, leads me to be¬ 
lieve that in this species, as in B. erythronotus , the male as¬ 
sumes a plumage resembling that of the adult female, inter¬ 
mediately between its first dress and the final stage of its 
adult coloration. 
I believe that the plumage described by Mr. Sharpe as 
“ adult" is that of the adult male only, and that the adult 
female is always rufous on the back, and more or less so on 
the under surface also. 
Assuming this view to be correct, the following are the 
measurements of two males and four females preserved in the 
Norwich Museum, all of which are either nearly or fully 
adult:— 
* The “ blackish ” tint of the slate-coloured parts of the plumage in 
this specimen is indicative of its not being a fully mature bird, the slate- 
coloured portions of the plumage being a clear grey in fully adult birds of 
both sexes. 
