530 EXPERIMENT STATION RECORD. 



detailed description is given of the methods of examination of l)irds' stomachs in the 

 laboratory and the method of making observations on feeding habits in the field. 



The stomach contents of 4,27o sparrows killed in various parts of the country dur- 

 ing different months of the year were examined. It was found that mineral matter 

 constituted from jij to 5 of the total stomach contents. From 25 to 35 per cent of 

 the diet for the whole year consisted of animal matter, chiefly insects, the latter con- 

 stituting from 10 to 20 per cent of the year's food. Theinsects eaten included grass- 

 hoppers, beetles, and caterpillars, as well as the representatives of various other 

 groups. The main food of sparrows consists of seeds of grasses and weeds. The 

 noneconomic portion of food eaten by sparrows was found to be chiefly insects, 

 spiders, snails, and wild fruit. Sparrows cause some damage to agriculture by destroy- 

 ing useful insects and cultivated crops, such as grain and fruits. Grain and cultivated 

 fruits, however, form no significant part of the food of sparrows, except in case of the 

 English sparrow. Of 19 species of native sparrows only 2 were found to have eaten 

 grain. The sparrows, including the English sparrow, are useful destroyers of weed 

 seeds. As a rule, the weed seeds are cracked or otherwise injured, so that they can 

 not germinate when vented from the body. The principal weed seeds which are fed 

 upon by sparrows are those of ragweed, pigeon grass, smartweed, purslane, crab grass, 

 lamb's quarters, chickweed, and amaranth. This work is done chiefly in the fall and 

 winter and early spring. During this time the seeds of various weeds constitute about 

 three-fourths of the food of 20 species of native sparrows. It is estimated that the 

 native sparrows may destroy 90 per cent of the seeds of pigeon grass and ragweed 

 within 2 months. The benefits derived from the feeding habits of sparrows are 

 believed to be from 5 to 10 times as great as the injuries produced. 



Notes are given on the individual habits of different species of sparrows. These 

 observations were carried on especially at a farm near the base of one of the White 

 Mountains; at Marshall Hall, Md. ; and in the District of Columbia. In order to 

 determine the possible agency of sparrows in distributing weed seeds, examinations 

 were made which disclosed the fact that comparativel}' few seeds pass through the 

 alimentary tract without being destroyed. 



In the spring of 1898 feeding experiments were made with a song sparrow, a junco, 

 and a white-throated sparrow^ in captivity. It was found that these birds were 

 readily induced to eat various beetles and bugs which were provided with volatile 

 irritating fluids for protection. In the winter of 1900, 7 English sparrows in cap- 

 tivity were fed upon the seeds of different weeds, for the purpose of determining how 

 thoroughly these seeds were destroyed. The seeds of climbing false buckwheat, rag- 

 weed, lamb's quarters, and amaranth were entirely destroyed. Two sparrows were 

 fed with 100 seeds of crab grass and gravel was furnished to aid grinding power of 

 the birds' gizzards. All of the seeds were destroyed. In another expenment 500 

 crab grass seeds were fed to the same sparrows without the addition of gravel. The 

 result of this exijeriment was the same as that of the preceding one. Of 1,600 seeds 

 of crab grass which had passed through the alimentary tract of the sparrows, not a 

 single one was found to germinate. 



A large portion of the bulletin is occupied wnth a special discussion of the feeding 

 habits of the different sparrows which were studied. In the stomachs of 82 English 

 sparrows, insects constituted 2 ])er cent and seeds 98 per cent of the food. The grain 

 which had l)een consumed by the birds formed 74 per cent of the eiitire food for the 

 year. An examination of the contents of the stomachs of 50 nestlings showed that 

 one-third of their food was also grain. The Ejiglish sparrow was found to feed 

 less on useful insects than any other bird which appears to have been studied, but 

 the injury to grain from attacks of the English sparrow is (considered as more than 

 counterbalancing all the benefits which accrue from its presence in the country. 



The birds of North and. Middle America, R. Ridgway {Smithsn. Inst., U. S. 

 Nal. Mia. Bnl. 50, 1901, pt. 1, pp. XVII + 715, plf<. W).—k description is given of all 

 species, subspecies, and forms of birds found on tlic continent of North America 



