88 
BIRDS AS DESTROYERS OF INSECTS. 
they could be carried by tbe wind. A swift-winged bird may 
drop cberry stones a thousand miles from the tree they grow 
on ; a hawk, in tearing a pigeon, may scatter from its crop the 
still fresh rice it had swallowed at a distance of ten degrees of 
latitude,* and thus the occurrence of isolated plants in situations 
where their presence cannot otherwise well be explained, is 
easily accounted for. There is a large class of seeds apparently 
specially fitted by nature for dissemination by animals. 1 
refer to those which attach themselves, by means of hooks, or 
by viscous juices, to the coats of quadrupeds and the feathers 
of birds, and are thus transported w r herever their living vehi¬ 
cles may chance to wander. Some birds, too, deliberately 
bury seeds, not indeed with a foresight aiming directly at the 
propagation of the plant, but from apparently purposeless 
secretiveness, or as a mode of preserving food for future use. 
An unfortunate popular error greatly magnifies the injury 
done to the crops of grain and leguminous vegetables by wild 
birds. Very many of those generally supposed to consume 
large quantities of the seeds of cultivated plants really feed 
almost exclusively upon insects, and frequent the wheatfields, 
not for the sake of the grain, but for the eggs, larvae, and fly 
of the multiplied tribes of insect life which are so destructive 
to the harvests. This fact has been so well established by the 
examination of the stomachs of great numbers of birds in 
Europe and bTew England, at different seasons of the year, 
that it is no longer open to doubt, and it appears highly prob¬ 
able that even the species which consume more or less grain 
generally make amends, by destroying insects whose ravages 
would have been still more injurious.f On this subject, we 
* Pigeons were shot near Albany, in New York, a few years ago, with 
green rice in their crops, which it was thought must have been growing, a 
very few hours before, at the distance of seven or eight hundred miles. 
t Professor Treadwell, of Massachusetts, found that a half-grown 
American robin in confinement ate in one day sixty-eight earthworms, 
weighing together nearly once and a half as much as the bird himself, and 
another had previously starved upon a daily allowance of eight or ten 
worms, or about twenty per cent, of his own weight. The largest of these 
