GENUS I. 
FALCO , LiNNiEus. 
I. FALCO COO PERU, BONAPARTE. — COOPER’S HAWK. 
BONAPARTE, PLATE X. FIG. I. 
Buffon complained of the difficulty of writing a 
history of birds, because he already knew eight hundred 
species, and supposed that there might actually exist 
fifteen hundred, or even, said he, venturing as he thought 
to the limit of probability, two thousand ! What then 
would be his embarrassment at present, when nearly 
six thousand species are known, and fresh discoveries 
are daily augmenting the number ? 
The difficulties attending a general work on this 
subject are not, perhaps, experienced in an equal degree 
by one who confines himself to the history of a parti- 
cular group, or of the species inhabiting a single district. 
Nevertheless, in a work like the present, which is not 
a monograpliy limited to one genus or family, but 
embraces within its scope species belonging to all the 
different tribes, it is requisite, in order to explain their 
various relations and analogies, that the author should 
be more or less acquainted with the whole system of 
nature. To attempt, without the aid of methodical 
arrangement, a subject so vast, and apparently unlimited, 
would be hopeless. Hence the importance of a correct 
system of classification ; and the construction of one 
which shall exhibit, as far as practicable, the true 
affinities of objects, has exercised the attention of the 
most powerful minds that have been employed in the 
study of nature. 
