COOPER'S HAWK. 261 
The difficulties attending a general work on this subject are 
not, perhaps, experienced in an equal degree by one who con- 
fines himself to the history of a particular group, or of the 
species inhabiting a single district. Nevertheless, in a work 
like the present, which is not a monography limited to one 
genus or family, but embraces within its scope species belong- 
ing to all the different tribes, it is requisite, in order to ex- 
plain 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 arrange- 
ment, a subject so vast, and apparently unlimited, would be 
hopeless. Hence the importance of a correct system of clas- 
sification ; 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. 
That division of the feathered class popularly called birds 
of prey has always been recognised as a separate and well- 
defined group. In the Linnean System they form the order 
ACCIPITRES, and were, by that father of the science, distributed 
into three great natural divisions, which comprise nearly, if 
not quite, one-fifteenth part of all the known species of birds. 
The ulterior arrangement of one of these groups, the genus 
Falco of Linné, at present composed of between two and three 
hundred species, has much divided the opinions of naturalists. 
From the majestic eagle, the terror of the husbandman, to the 
feeblest hawk, preying on grasshoppers, it is undeniable that 
there exists in all these birds a great resemblance in some of 
the most prominent characteristics, which, being found to pre- 
dominate in the fish-hawk, as well as the kite, and all other 
species of the falcon tribe, however dissimilar, indicate their 
separation as a peculiar family from all other birds. But that 
they are susceptible of division into smaller groups of inferior 
rank, no practical ornithologist will for a moment deny. 
Whether these minor groups shall be considered as trivial 
and secondary, or whether some of them ought not to be 
