PLEA FOR THE BIRDS. 109 



with the harmonious operations of Nature, the insects are* 

 kept down to a point at which their numbers are not 

 sufficient to commit any perceptible ravages. The birds, 

 their natural destroyers, are allowed to live, and their 

 numbers keep pace with the insects they devour. In cul- 

 tivated tracts, on the contrary, a different state of things 

 exists. Man has destroyed the forests, and raised up 

 gardens and orchards in their place. The wild pasture 

 has become arable meadow, and the whortleberry grounds 

 have been changed into cornfields. New races of beetles 

 and other insects, which are attached to the cultivated 

 vegetables, increase and multiply in the same proportion. 

 If man would permit, the birds that feed upon these in- 

 sects would keep pace with their increase, and prevent 

 the damage they cause to vegetation. But, too avaricious 

 to allow the birds to live, lest they should plunder fruit 

 enough to pay them the wages for their useful labors, he 

 destroys the exterminator of vermin, and thus, to save a 

 little of his fruit from the birds, he sacrifices his orchards 

 to the insects. 



If any species of birds were exterminated, those tribes 

 of insects which are their natural food would become 

 exceedingly abundant. Inasmuch as the atmosphere, if 

 the swallows were to become extinct, would be rendered 

 unfit for respiration, by an increased multitude of gnats 

 and smaller insects; so, were the sparrow tribes to be- 

 come extinct, vegetation would immediately suffer from 

 an increase of caterpillars, curculios, and other pests of 

 our orchards. We may say the same of other insects 

 with relation to other birds. It is therefore plainly for 

 the interest of the farmer and the horticulturist to use all 

 means for the preservation of birds of every species. 

 There is no danger likely to arise from their excessive 

 multiplication. The number of each species cannot ex- 

 ceed that limit beyond which they could not be supplied 



