. 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 . ne of these tiny insectsin one minute. The pair continued eating at this rate forforty minutes. Mr. Mosher states that they must have eatenconsiderably over seven thousand plant lice in that time. Itwould seem impossible for the birds to crowd that numberof insects into their stomachs; but we must remember thatthe insects were infinitesimal in size, soft-bodied, easily com-p
. 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 . ne of these tiny insectsin one minute. The pair continued eating at this rate forforty minutes. Mr. Mosher states that they must have eatenconsiderably over seven thousand plant lice in that time. Itwould seem impossible for the birds to crowd that numberof insects into their stomachs; but we must remember thatthe insects were infinitesimal in size, soft-bodied, easily com-pressed in the stomach, and quickly digested, so that by thetime a part were eaten those first taken would be well dis-posed of, leaving room for more. Mr. Mosher is a verycareful, painstaking, and trustworthy observer ; undoubtedlyhis statement is accurate; but, to eliminate any possibilityof error, we will assume for purposes of calculation thatthey ate only thirty-five hundred in an hour. A pair of Yellow-throats (presumably the same) were seento come daily and many times each day to the birch treeswhich were infested with these aphids. Probably they spentat least three hours each day feeding on these insects. If. VALUE OF BIRDS TO MAN. 63 the two birds ate only thirty-five hundred an liour for threehours a day, they would consume ten thousand five hundredaphids each day, or seventy-three thousand five hundred ina week. It requires nodraft on the imaginationto see how such appe-tites may become usefulto the farmer if they aresatiated on his insectenemies. Two Scarlet Tanagerswere seen eating very ^ •> Pig. 26. —Yellow-throat catching birch aphids. small caterpillars of the gipsy moth for eighteen minutes, at the rate of thirty-fivea minute. These birds spent much time in that way. Ifwe assume that they ate caterpillars at this rate for only anhour each day, they must have consumed daily twenty-onehundred caterpillars, or fourteen thousand seven hundredin a week. Such a
Size: 1955px × 1278px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjectbirds, bookyear1913
