Mr. R, B. Sharpe’s Catalogue of Accipitres. B23 
brown, with rufous edgings, which are broadest on the lower 
interscapulars, the upper tail-coverts, the secondaries, and the 
tertials; all the quill-feathers of the wing are crossed by 
blackish-brown bars, which are broadest on the primaries, 
The tail has two* broad blackish-brown transverse bars, with 
an intervening grey bar; below the lower dark bar is a nar- 
row rufous line, succeeded by an indistinct brown one; this 
is followed by another rufous line, and that by the tip of the 
tail, which is whitish. 
There appear to be two distinct types of color ation amongst 
the immature birds of this species—one, of which the nestling 
above described may serve as an example, in which a pure 
white preponderates on the head, neck, and underparts, and 
which is the more frequent of the two; the other, a much 
darker type, which is not so common, and to which I propose to 
refer more fully after I have noticed some additional specimens 
of young birds in the white-breasted plumage. Mr. Sharpe 
treats these two phases of coloration as consecutive, supposing 
the darker to be the younger of the two; but this is, I think, 
disproved by the existence both of the white-breasted nestling 
above described, and of specimens in course of change from 
that stage and also from the dark phase of plumage into the 
adult dress. 
The dark plumage is, I believe, a peculiarity incident to 
some young birds of this species and not to others, the 
. case being almost a parallel one to that of the dark and 
light phases of plumage amongst the immature examples of 
Pernis apivorus and P. ptilorhynchus ; and in this instance, as 
in that, though I think less frequently, young birds of an 
intermediate complexion, as regards coloration, also occa- 
sionally occur. 
It may be convenient to attach a number to the several 
specimens to which I am about to refer; and commencing by 
calling the Demerara nestling, already described, “ No. 1,” 
I would now refer to No. 2 on my list, an example from 
Ecuador, which has been kindly lent to me by Messrs. Salvin 
* The small number of these bars is probably due to the tail not being 
quite fully grown, 
Z2 
