Mr. R. B. Sharpe’s Catalogue of Accipitres. 353 
The geographical range of H. leuconotus is stated by Mr. 
Sharpe to be ^^North-Eastern and Southern Africabut 
it also extends to Senegal, an adult specimen from Bissao 
being preserved in the Norwich Museum. There seems, in 
fact, to be but little, if any, diflPerence between the geo¬ 
graphical ranges of H. leuconotus and H. ecaudatus) and 
Mr. Sharpe remarks that the former ^^is perhaps the fully 
adult bird of the latter; but in this view I am not dis¬ 
posed to agree, as many specimens have been kept in con¬ 
finement in this country, amongst which I have never heard 
of one having changed from a rufous back to a cream-coloured, 
or vice versd^. I ought, however, to add that in an adult 
specimen of H. leuconotus, which I recently examined in the 
Strickland Collection at Cambridge, there is a decided ap¬ 
pearance of faded rufous on the tail, though not on the back. 
Von Heuglin has some noteworthy remarks on this subject 
in his Ornithologie Nord-Ost Afrika^s,^ vol. i. p. 80, of w^hich 
the following is a translation ;—Specimens with white back 
and tail are found in the whole of Africa. Vierthaler ob¬ 
served the transition through moulting from the red brown- 
to the white-backed bird, whilst I have shot a newly-moulted 
one of the last-named plumage the dorsal feathers of which 
were only partly grown, but these also showed the white 
plumage. We also saw plainly, several times, pairs of the 
white-backed variety. Most of the specimens we found on 
the White Nile and in Kordofan were white-backed; the 
Abyssinian birds were all brown-backed,^^ 
I venture to think that Vierthaler^’s note, referred to in the 
above extract, only implies that he had observed a specimen 
in confinement to change from the immature brown plumage 
to the white-backed adult dress, and not from the rufous- 
backed adult plumage to the white-backed. The following is 
a translation of Vierthaler^s memorandum on the subject, 
which was made during his journey on the Blue Nile, and 
which, it must be admitted, is not so precise as could be 
In the Zoological Society’s Gardens are two whatever red-hacked 
specimens, received in 1873, which show no signs of change into the 
white hacked form.—E dd,] 
SISR. IV.-VOL. II. 2 B 
