1883.] UTILITY OF BIRDS IN AGRICULTURE. 89 



I will pass over quickly the wrens, as strongly beneficial to gar- 

 dens, and plants about the house, and hedge shrubs, from the 

 numbers of caterpillars they eat; the flycatchers, which are of 

 course beneficial; the cedar-bird, who, between taking the habits 

 of a flycatcher at one time and of a most miserable and despicable 

 wretch of a fruit eater at another, renders difficult the question as 

 to which counterbalances the other in the long run ; the Maryland 

 yellow-throat ground warbler, so strict a guardian of the birches 

 and alders of the hedges, who eats caterpillars that affect these 

 shrubs materially; the thrushes; the warblers; and the vireos — all 

 of which are of the greatest benefit to mankind — and pass at 

 once to 



PART III. 



THE UTILITY OF BIRDS IN MIGRATION. 



I am now aware that I have come to the most difficult, as it is 

 the most important part of my subject, — the utility of birds in 

 migration. To treat of the utility of birds were a matter of com- 

 parative ease, as werp it also to speak of them in their migration, 

 but it is the combibation, — the utility in migration that is the main 

 point which I wish to emphasize. In order to do this we must 

 first find out what birds migrate — in any numbers, at least — then: 

 from whence, and to where, do they migrate? In the next place 

 we must find: what species are beneficial and why, and what inju- 

 rious and why, to the farmer and agriculturist? We therefore 

 omit mention of those species occupying a medium position or 

 whose economy is not yet thoroughly understood. We will omit 

 entirely the raptores or birds of prey, with the majority of all the 

 other orders except the insessores or perching birds proper, and 

 confine ourselves to them alone. Let us proceed then to pick out 

 those species of birds which are beneficial or injurious to the 

 farmer in their migration, and see from whence they come and 

 whither they go, and note their economy. 



We find that the great body of birds migrate twice a year, — in 

 the spring, during the months of April and May, generally ending 

 before the end of the latter month ; and in the fall during the 

 middle to the last of September, and so on until late into the 

 winter months. Birds migrating in the spring generally eat all 

 they can get hold of to pay for the winter's privations, in case they 

 have not had a full and usual allowance; in fall the birds are weak 



