. 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 . )lant lice in that time. Itwould seem impossible for the birds to crowd that numberof insects into their stomachs; l)ut 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 Avould be well dis-posed of, leaving room for more. Mr. Mosher is a ver
. 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 . )lant lice in that time. Itwould seem impossible for the birds to crowd that numberof insects into their stomachs; l)ut 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 Avould 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-tlu-oats (presumably the same) were seento come daily and many times each day to the birch treeswhich were infested with these aphids. Prolmbly 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 iiour for three hours a day, they would consume ten thousand tive hundred aphids each day, or seventy-three thousand five hundred in a week. It re(i[uires no draft on the imagination to see how such a]>pe- tites may become useful to the farmer if they are satiated on his insect enemies. Two Scarlet Tanagerswere seen eating very ^ , • Fig. 26. —Yellow-tliroat catching biix-liapliids. 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 number of caterpillars would lie suffi-cient to defoliate two average apple trees, and so preventfruitage. The removal of these caterpillars might enab
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