. 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 . ^ a vigor-ous Crow at liberty that the food taken by a prisoner insolitary confinement, or that consumed by a sedentary clerk,bears to the amount required by a strong man at hard labor,or by a prize-fighter in training. The amount of food taken by young l:)irds could not bedisposed of by such limited powers of digestion as are givento other animals. What a wonderful contrast
. 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 . ^ a vigor-ous Crow at liberty that the food taken by a prisoner insolitary confinement, or that consumed by a sedentary clerk,bears to the amount required by a strong man at hard labor,or by a prize-fighter in training. The amount of food taken by young l:)irds could not bedisposed of by such limited powers of digestion as are givento other animals. What a wonderful contrast is presentedbetween the quantity of food required by the hot-blooded,quick-pulsing, active bird, and that needed by the cold-blooded vertebrates. Many reptiles can live for monthswithout food. Even some of the mammals do not eat atall during their hibernation. Birds of New England, hy Edward A. Samuels, 1870, p. 359.^ Birds in their Relations to Man, by Clarence M. Weed and Ned Dearborn,1!)03. p. 01. VALUE OF BlllDS TO MAN. 49. The Time required for Assimilation of Food. If we assume that the stomach and oesophagus of a youngCrow can contain but an ounce of food, then the bird wouldbe required to digest from eight to twelve meals a day,according to its appetite and opportunity. The question atonce arises, IIow can any digestive system complete sucli atask? Experiments were made with our young Crows todetermine the time required fordigestion. The birds were keptwithout food until the stomachand intestines were were then fed insects eggs,in the belief that some parts ofthe shells would escape the grind-ing processes of the stomach andbe voided in the excreta. Sub-sequent occurrences justified thisbelief. Ten experiments of thiskind were made with the twobirds. From the time when the birdsbegan to feed until the time when the first eggshells weredropped in the excreta there elapsed, on the average, onehour, twenty-nine minutes and forty-five seconds. Theshortest time w
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