116 
ON THE CLASSIFICATION OP BIRDS. 
fact, which is to turn these seeds into nourishment. 
If there was little variation in the size or strength of 
the bills of the tanagers, the inevitable consequence 
would follow, that they would only be able to feed 
upon seeds or nuts varying hut very slightly in their 
size and hardness: and hence it would follow, that 
innumerable other sorts, which either did not come up 
to this standard, or much exceedetl it, would be left 
untouched, and, as food to the animal world, jierfectly 
useless ; at least, so far as we can conjecture. To pre- 
vent, therefore, such a waste of her vegetable aliments, 
nature has created in the finches a vast family of birds, 
expressly for the purpose of subsisting upon them ; and 
that these birds should be qualified to partake of all the 
different sorts, from the softest to the hardest, she has 
given to these creatures a corresponding variety in the 
shape and strengtli of their bills. We are much 
strengthened in this hypothesis, by observing something 
of the same principle in operation, although, upon a 
more limited scale, among the finches of Europe. How 
great, for instance, is the disparity of size between the 
bill of our hawfinch, greenfinch, and linnet ; and yet 
these birds, so far from belonging, as is generally sup- 
posed, to very distinct and even remote genera, actually 
follow each other (according 
to our analysis of their affi- 
nities), without the least inter- 
ruption, as subgenera. Every 
one, in fact, must perceive the 
dose relation of the common 
^ hnnet {Linaria,Jig. 1 64. o), to 
the green linnet (Chloris, b), 
and this again to the hawfinch 
{Coccothraustes, c), with which 
It might, perhaps, be equally as- 
sociated, as only a slightly aber- 
rant species. Such a disparity 
in regard to the hills can scarcely be fomid in any other 
groups in ornithology. 
