. Useful birds and their protection. Containing brief descriptions of the more common and useful species of Massachusetts, with accounts of their food habits, and a chapter on the means of attracting and protecting birds. Birds; Birds. Fig. 26.— Yellow-throat catching birch aphidB. VALUE OF BIRDS TO MAN. 63 the two birds ate oiil}'^ thirty-five hundred an liour for tliree hours a day, they would consume ten thousand five hundred aphids each day, or seventy-three thousand five hundred in a weeli. It requires no draft on the imagination to see how such appe- tites may become useful to the farmer
. Useful birds and their protection. Containing brief descriptions of the more common and useful species of Massachusetts, with accounts of their food habits, and a chapter on the means of attracting and protecting birds. Birds; Birds. Fig. 26.— Yellow-throat catching birch aphidB. VALUE OF BIRDS TO MAN. 63 the two birds ate oiil}'^ thirty-five hundred an liour for tliree hours a day, they would consume ten thousand five hundred aphids each day, or seventy-three thousand five hundred in a weeli. It requires no draft on the imagination to see how such appe- tites may become useful to the farmer if they are satiated on his insect enemies. Two Scarlet Tanagers were seen eating very small caterpillars of the gipsy moth for eighteen minutes, at the rate of thirty-five a minute. These birds spent much time in that way. If we assume that they ate caterpillars at this rate for only an hour each day, they must have consumed daily twenty-one hundred caterpillars, or fourteen thousand seven hundred in a week. Such a number of caterpillars would be suffi- cient to defoliate two average apple trees, and so prevent fruitage. The removal of these caterpillars might enable the trees to bear a full crop. It is easily possible, therefore, for a single pair of these birds in a week's time to save the fruit of two average apple trees, — a crop worth from two to five dollars or more, according to the productiveness of the trees and the price paid for apples. BIRDS SAVE TREES AND CROPS FROM DESTRUCTION. Since birds evidently operate to check insect outbreaks, it follows that in their capacity of insect destroyers they must in many instances have saved trees and crops from destruc- tion by insect pests. If, however, we turn to the literature of agriculture, entomology, and ornithology, we shall not find it replete with such instances. Still, there are enough on record to show that conspicuous services of birds have been noted occasionally ; and I am convinced by my own experi- ence th
Size: 1956px × 1278px
Photo credit: © Central Historic Books / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, bookpublisherb, booksubjectbirds
