SPECIES 9. FALCO PENNSYLVANICUS. 
SLATE-COLOURED HAWK.* 
[Plate XLVL— Fig. 1.] 
This elegant and spirited little Hawk is a native of Pennsyl- 
vania, and of the Atlantic states generally; and is now for the 
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, very irregular, and swiftly; 
preys on lizards, mice and small birds, and is an active and da- 
ring little hunter. It is drawn of full size, from a very beauti- 
ful specimen shot in the neighbourhood of Philadelphia. The 
bird within his grasp is the Tanagra rubra, or Black-winged 
Red-bird, in its green or first year’s dress. In the spring of the 
succeeding year the green and yellow plumage of this bird be- 
comes of a most splendid scarlet, and the wings and tail deepen 
into a glossy black. 
The great difficulty of accurately discriminating between dif- 
ferent species of the Hawk tribe, on account of the various ap- 
pearances 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, figured in plate XLV of this work; 
for such are the changes of colour to which many individuals 
* By comparing' this bird with the Sharp-shinned Hawk, it will be obvious 
that Wilson had good reason for his first opinion, that they are identical; al- 
though he subsequently came to a contrary conclusion. It is probable that 
they will be found to be the same, and that this is the adult, and the Sharp- 
shinned Hawk the young bird. If this be the case, the name velox, which was 
first given to this species by Wilson, must be retained; unless indeed it should 
prove to be identical with the F. fiiscus of authors, as asserted by Prince Musig- 
nano; in which event this latter name must of course, having the priority, be 
adopted. 
