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 otf 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 Aveight, 

 while w^hen 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 weiglit. 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 



