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

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Identifier: usefulbirdstheir00forbu (find matches)
Title: 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
Year: 1907 (1900s)
Authors: Forbush, Edward Howe, 1858-1929 Massachusetts. State Board of Agriculture
Subjects: Birds Birds
Publisher: (Boston, Mass.
Contributing Library: Smithsonian Libraries
Digitizing Sponsor: Smithsonian Libraries

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Medford, Mass. He made a special study ofthe American silkworm (TeleapoJi/phemus). Regarding itsfood and growth he says : — It is astonishing how rapidly the larva grows, and one who has hadno experience in the matter could hardly believe what an amount offood is devoured by these little creatures. One experiment whic-h Imade can give some idea of it. When the young worm hatches out, it ^ A probable cause for this voracity in the case of herbivorous larvje is tliat thestomachs do not have tlie power of dissolving the vegetable matter received intotliem, but merely of extracting from it a juice. This is proved both by theirexcrement, which consists of coiled-up and hardened particles of leaf, which,wlien put into water, expand like tea, and by the great proi)ortion which theexcrement bears to the quantity of food consumed (Kirby and Spences Ento-mology, p. 259). ^ Our Insect Enemies, by J. A. Lintner. Sixteenth Annual Report, New.Tersey State Board of Agriculture, 1«8,S-.S0, p. 295.
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VALUE OF BIRDS TO MAN. 31 weighs one-twentieth of a grain ; when ten days old, it weighs one-halfa grain, or ten times the original weight; when twenty days old, itweighs three grains, or sixty times the original weight; wlien thirty daysold, it weighs thirty-one grains, or six hundred and twenty times theoriginal weight; when forty days old, it weighs ninety grains, or eight-een hundred times the original weight; and when fifty-six days old, itweighs two hundred and seven grains, or forty-one hundred and fortytimes the original weight. When a worm is thirty days old, it will have consumed about ninetygrains of food; Init wlien fifty-six days old it is fully grown, and hasconsumed not less than one hundred and twenty oak leaves, weighingthree-fourths of a pound; besides this, it has drunk not less than one^half an ounce of water. So the food taken by a single silkworm infifty-six days ecjuals in weight eighty-six thousand times the primitiveweight of the worm. Of this, about one-fourt

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