SLATE COLOURED HAWK. 
71 
is now for tlie first time introduced to the notice of 
the public. It frequents the more settled parts of the 
country, chiefly in winter; is at all times a scarce 
species; flies wide, in a very irregular manner, and 
swiftly ; preys on lizards,' mice, and small birds, and 
is an active and daring little hunter. 
The great difficulty of accurately discriminating 
between different species of the hawk tribe, on account 
of the various appearances they assume at different 
periods of their long lives, at first excited a suspicion 
that this might be one of those with which I was 
already acquainted, in a different dress, namely the 
sharp-shinned hawk just described; for such are the 
changes of colour to which many individuals of this 
genus are subject, that, unless the naturalist has recourse 
to those parts that are subject to little or no alteration 
in the full grown bird, viz. the particular conformation 
of the legs, nostril, tail, and the relative length of the 
latter to that of the wings, also the peculiar character 
of the countenance, he will frequently be deceived. By 
comparing these, the same species may often be detected 
under a very different garb. Were all these changes 
accurately known, there is no doubt but the number of 
species of this tribe, at present enumerated, would be 
greatly diminished, the same bird having been described 
by certain writers three, four, and even five different 
times as so many distinct species. Testing, however, 
the present hawk by the rules above-mentioned, I have 
no hesitation in considering it as a species different 
from any hitherto described; and I have classed it 
accordingly. 
The slate-coloured hawk is eleven inches long, and 
twenty-one inches in extent ; bill, blue black ; cere and 
sides of the mouth, dull green ; eyelid, yellow ; eye, deep 
sunk under the projecting eyebrow, and of a fiery 
orange colour; upper parts of a fine slate; primaries, 
brown black, and, as well as the secondaries, barred 
with dusky ; scapulars, spotted with white and brown, 
which is not seen unless the plumage be separated by 
the hand ; all the feathers above are shafted with 
