388 Mr. H. W. Henshaw on the various 
It is not, however, of the bird's general habits that I 
wonld here speak, but of its plumages, which, it would seem, 
have not been at all well understood. Of these there are two 
which are entirely distinct, viz. a light and a dark phase, each 
having two stages, a juvenile and an adult. So diiTerent are 
these phases that extreme examples might well be mistaken 
for different species. In life the adult of the light phase 
has the appearance of a white or albino Ha\Yk ; while the 
adult of the dark phase looks quite black or melanistic. 
This dichromatism may aptly be compared with that which 
distinguishes the American Screech-Owl (Megascops asiu), 
with its red and grey phases, since it characterizes the bird 
in all stages of growth, is dependent upon neither sex nor 
season, and mating birds may or may not be alike in 
colour. 
The two phases of this Hawk may be described as 
follows : — • 
Light Phase. 
Adult stage. — Head and hind-neck white, or buffy white, 
the feathers of the former with narrow blackish shaft- 
streaks, those of the latter tipped with large roundish spots 
of the same. Sides of head and neck buffy, with more or 
less brown ; back blackish brown ; rump lighter brown tinged 
with ochraceous ; primaries blackish brown, the inner webs 
above the notch white ; inner webs of secondaries black 
barred, and tipped, as are the wing-coverts, with whitish and 
ochraceous ; tail lighter brown, with faint marblings and 
a wash of ochraceous ; rectrices with eight or nine narrow, 
zigzag, more or less well-defined, blackish bars, w^hich rarely 
entirely cross the whitish inner webs ; under parts buff or 
rusty buff, with a few feathers (sometimes but one or two) 
on the flanks with brown shaft-streaks and small terminal 
spots of same. Legs and feet greenish yellow; soles liglit 
yellow ; bill blackish, but plumbeous at the base of the 
lower mandible; iris light hazel. 
Juvenile stage. — Above and on the sides of the head 
chocolate-brown, deepest on the hind-neck; the feathers 
lightly bordered with greyish and rusty ; rectrices ashy 
brown, with irregular bars of blackish across each feather ; 
