VALUE OF BIRDS TO MAN. 47 
than usual was needed. ‘The next day about twenty ounces 
of food, containing a large proportion of animal matter, were 
given; and on August 30 the larger bird had again regained 
its weight of seventeen ounces, while the other held its own. 
So far the experiment seemed to show that when they were 
fed from twenty to twenty-five ounces of a ration containing 
both animal and vegetable food the birds held their own or 
gained slightly ; but if fed less than twenty ounces of this 
ration, one or both of the birds fell off in weight. 
After the death of one bird the other and all its food were 
weighed daily. All opportunity to secure scattered grain or 
other food than that weighed was denied. The greatest 
weight reached by this bird was eighteen and one-half ounces 
on September 13, on which date it was fed as much corn, 
cucumber, and tomato as it cared to eat, also a frog, two 
toads, twenty-seven grasshoppers, thirty-one. borers, eight 
beetles, and eighteen crickets. The record of the twelve 
days during which this bird was alone seems to show that 
less than eight ounces of food daily was hardly sufficient for 
its needs, as on a less amount it tended to lose in weight, 
while when the amount was increased to ten ounces or more 
the tendency toward a daily gain in weight was marked. 
When the quantity of food given these birds was largely 
reduced in any one day, there was a corresponding reduction 
in their weight. On September 13 the larger Crow was given 
only two ounces of tomato, fifty-six grasshoppers, twelve 
crickets, and a little grain, —in all, not much over three 
ounces of food. The next morning it had lost one and 
one-half ounces in weight. The fact that a bird, while in 
confinement and without a great amount of exercise, could 
lose nearly ten per cent. of its weight in a single day, even 
when fed a quantity of food equal to about one-sixth its 
weight, shows how dependent birds are upon their supply 
of food. . 
If this single experiment can be regarded as conclusive, 
we may assume that young Crows, when fledged, absolutely 
require a daily amount of food equal to about one-half their 
own weight; and it is evident that they will consume much 
more than this to their own advantage if they can get it. It 
