BLUE HAWK, OR HEN-HARRIER. 
395 
inches, to the tip of the tail, which is also but slightly rounded 
in the latter, while in the ash-coloured it is cuneiform. Other 
minor differences are besides observable in the respective sexes 
and states of both ; but as those we have indicated are the only 
ones that permanently exist, and may be found at all times, we 
shall not dwell on the others, especially as Montague’s species 
appears not to inhabit America. We think proper to observe, 
however, that the adult male of Falco cineraceus has the pri- 
maries wholly black beneath, while that of the F, cyaneus has 
them black only from the middle to the point ; and that the 
tail-feathers, pure white in the latter, are in the former spotted 
beneath. The female in our species is larger than the corre- 
sponding sex of the other, though the males in both are nearly 
of equal size ; and the collar that surrounds the face is strongly 
marked in ours, whereas it is but little apparent in the other. 
The F, cineraceus has two white spots near the eyes, which 
are not in the F. cyaneus. The young of the former is beneath 
rusty without spots. Thus, slight but constant differences are 
seen to represent a species, while the most striking discrepan- 
cies in colour, size, and (not in this, but in other instances) 
even of form, prove mere variations of sex or age ! We can- 
not wonder at the two real species having always been con- 
founded amidst the chaotic indications of the present 
Even Wilson was not free from the error which had pre- 
vailed for so long a period in scientific Europe, that the ring- 
tail and hen-harrier were two species. Though he did not 
publish a figure of the present in the adult plumage of the 
male, he was well acquainted with it as an inhabitant of the 
Southern States ; for there can be no doubt that it is the much 
desired blue hawk which he was so anxious to procure ; the 
only land bird he intended to add to his Ornithology, or at 
least the only one he left registered in his posthumous list. It 
was chiefly because he was not aware of this fact, and thought 
that no blue hawk existed in America corresponding to the 
European hen-harrier, that Mr Sabine, in the Appendix to 
