48 The Horticultural Value of the Crow. 



says that a pair of sparrows will destroy 3,360 caterpillars for a week's 

 family supplies. For four weeks, at the lowest estimate, the young of our 

 sparrows are fed on this diet ; and the family that the crow destroys would, 

 in that time, eat at least 13,440 noxious insects ; and as they feed more 

 or less upon this same diet during their stay with us, killing certainly as 

 many as fifty insects each, daily, the family would devour 200 per diem, 

 or, before they leave us in September, as many as 20,000. The war- 

 blers are entirely insectivorous, and we can certainly allow them as great 

 destructive capacity as the sparrows. The four that the crow destroys 

 would have devoured, before they leave us in autumn, at least 30,000 

 caterpillars and other insects. A pair of thrushes has been actually seen 

 to carry over a hundred insects, principally caterpillars, to their young in 

 an hour's time : if we suppose that the family mentioned above be fed for 

 only six hours in the day, they would eat six hundred per diem, at least, 

 while they remain in the nest ; which being three weeks, the amount would 

 be 12,600 ; and before they leave us in the fall, allowing only fifty each per 

 day, — a very small number, — they would, in the aggregate, kill 20,000 

 more. 



Now, we find that the crow in one day destroys birds that would, 

 together, eat 96,040 insects before they would leave us for their winter 

 homes, or about ninety-six times as many as it would eat in a day if its food 

 consisted entirely of them. It is therefore injurious, during the last half 

 of May, — keeping our original calculation in view, — 598 units. 



During the whole month of June and the first half of July, while its 

 family are in the nest, it is at least doubly destructive ; for its young are 

 possessed of voracious appetites, requiring an abundance of food to supply 

 them. Allowing, then, that, of its and their diet, half consists, of insects 

 during this period, it is beneficial about 46 units ; but, as at least one-half 

 of the other half consists of young birds and eggs, it is injurious during the 

 same period at least 96 units daily, or 4,320 units for June and the 

 first half of July. The remaining quarter of its and their food during 

 this time consists of berries and various small seeds, and reptiles ; and 

 this diet may be considered as of neutral importance, economically speaking. 



During the last half of July, and through August and the first half of 

 September, its diet consists of about half insects and mice ; and the balance^, 

 of berries and small fruits. It is therefore, during this time, beneficial 



