THE TREES OF AMERICA. 23 



fact is not sufficiently regarded by the agriculturist. What farmer expects to 

 raise doves or domestic fowls, if he provide no dovecots or places for them to 

 breed in. 



As well might he expect the birds which guard his crops against the insect 

 armies, and cheer his labors with their music, to build their nests without the 

 shelter of bush or tree, or hatch their young, as is the fable in regard to Mother 

 Carey's chickens, in the air through which they soar and sing. But are the 

 birds so important to the farmer — (and if to him, to all, for we all depend upon 

 him for food) — as we regard them 1 We are too often so obstinate in our opin- 

 ions, or so careless in our habits of observation, as to learn wisdom only by sad 

 experience. Even the experience of others fails to arouse our attention, until 

 too late we find ourselves the victims of the inexorable law. The " open secret 

 of nature " lies spread out before us, and yet we fail to profit by it. 



We should remember one thing in regard to insects injurious to vegetation ; 

 that is, that they all undergo several transformations, and that the bird which 

 may shun them in one state may destroy myriads of them in another. Thus 

 the barn swallow does not, to my knowledge, destroy a single insect in its larva 

 or caterpillar state ; but he all day long, from early morn to gray evening, with 

 untiring wing and insatiable appetite, devours them by thousands, when, as 

 moths or butterflies, each one is capable of laying eggs enough to produce a 

 whole army of caterpillars. 



But do birds really do much to prevent the destruction of vegetation by in- 

 sects ? " In England," says Carpenter, " the caterpillars of the beetle kind — 

 especially those of the cockchafer — would speedily destroy the roots of all our 

 corn and grasses, were it not for the rook and other birds. In some parts of 

 the country, where rookeries have been destroyed, it has been found necessary 

 to restore them. In some of the eastern counties of England, a few years since, 

 the turnip crop, which is here considered so important, was nearly destroyed by 

 the turnip fly. This result was only prevented by the increase of domestic fowls 

 and the birds." Buffbn informs us that there was once danger that the Island 

 of Bourbon would be entirely devastated by locusts, their eggs having been 

 introduced with some plants from Madagascar. This result was, however. 



