. 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. 42 USEFUL BIRDS. fluids ; the chyle is drawn off by the lacteals, and tlie residue is excreted. The vigor, perfection, and rapidity of these processes in insect-eating birds are such as might be expected among animals of such high temperature, perfect respiration, and rapid circulation. The various dilations of the digestive tract serve well their purpose of ena
. 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. 42 USEFUL BIRDS. fluids ; the chyle is drawn off by the lacteals, and tlie residue is excreted. The vigor, perfection, and rapidity of these processes in insect-eating birds are such as might be expected among animals of such high temperature, perfect respiration, and rapid circulation. The various dilations of the digestive tract serve well their purpose of enabling the bird to consume the large amount of food necessary for its maintenance. Digestion is partic- ularly rapid in the growing young of most birds, for they require not only food sufficient to sustain life, but an extra supply as well to enable them to increase daily in size, and to grow, in a few days, those wonderful appendages that we call feathers. The Growth of Young Birds. The growth of many birds from the egg to the hour of flight requires less time than is needed by some insects to reach the flight stage. It is most significant that young birds can develop as rapidly as can many in- sects on which they feed, for it shows how readily, under favorable conditions, the increase of birds might keep proportion- ate pace with that of insects. "Weed and Dearborn, in their interesting manual, en- ^'S^'^onTZ^Z, titled "Bkds in their Eelations to Man," naked, blind, and help- state that they watclied four young Song less, with mouth open „ , i. e i.^ i ii. lor food. Reduced; bparrows that were out or the nest on the .ifter Herriek. eighth day. Mr. Owen records another instance where a brood of young Song Sparrows Avere fledged and left the nest within the same period.^ Probably this is exceptional; but many of the smaller birds rear their young from the egg to the first flight within two or three weeks. Mr. Owen found that on one particular day this family of
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