288 ANNUAL REPORTS OF DEPARTMENT OE AGRICULTURE. 



FOOD KABITS OF OTHER BIRDS. 



With a view to ascertaining the food habits of the vireos, exami- 

 nation of stomach contents has been continued and completed for 

 all but one species; similar work has been started on the English 

 sparrow, that its relation to constantly changing agricultural con- 

 ditions may be known ; and examination of the food of other species 

 has progressed so far as a limited force permitted. 



During the year two department bulletins were published, At- 

 tracting Birds to Public and Semipublic Reservations, and Food 

 Habits of the Mallard Ducks of the United States, and several 

 Farmers' Bulletins were revised. A report has been prepared on 

 the food of winter-bird visitants, including the pine and evening 

 grosbeaks, white-winged and red crossbills, hoary and common red- 

 polls, pine siskin, snow bunting, the various longspurs, and the 

 pipits. Another has also been prepared on the food of shoal-water 

 ducks, dealing with the gadwall, baldpate, green-winged, blue- 

 winged, and cinnamon teals, pintail, and wood duck. For educa- 

 tional purposes a lecture with lantern slides has been prepared on the 

 value of birds to agriculture. 



BIOLOGICAL INVESTIGATIONS. 



The work of the Division of Biological Investigations has been 

 seriously decreased, owing to the war. Two members of the scien- 

 tific staff were commissioned in the Sanitary Corps and were in 

 charge of rat-control work in France to safeguard Army supplies, 

 and others were detailed to certain phases of urgently needed eco- 

 nomic work. 



As has been the case during past years, the field and laboratory 

 work of the division has been conducted along broad lines helpful 

 to the various other activities of the bureau. These activities include 

 the enforcement of the migratory-bird treaty act; enforcement of the 

 Lacey Act regulating importations of, and interstate commerce in, 

 birds and mammals; the administration of the mammal and bird 

 reservations; general conservation of game birds and mammals; 

 and work relating to the economic relations of mammals and birds 

 to agriculture, forestry, and stock-raising. 



The card indexes covering. the distribution, abundance, and habits 

 of all the species of North American mammals and birds have been 

 greatly augmented during the year. These files contain data from 

 many sources, including reports by field parties of the bureau, notes 

 gleaned from correspondence and other outside sources, and records 

 from publications. 



DISTRIBUTION AND MIGRATION OF BIRDS. 



Owing to war conditions fewer volunteer observers than usual 

 reported on bird migration. Plowever, 250 observers sent in re- 

 ports from points throughout the United States and from many 

 localities in Canada and Alaska. Considerable progress was made 

 in compiling information from various publications on the distribu- 

 tion and migration of birds, adding materially to the files, which now 

 contain more than 1,350,000 cards. This source of information is 

 consulted daily in connection with the administration of the migra- 

 tory-bird treaty act and the investigations of the economic habits 

 of birds. 



