DIVISION OF BIOLOGICAL SURVEY. 37 



ECONOMIC RELATIONS OF BIRDS. 



During the year 2,980 birds' stomachs were received and 1,989 exam- 

 ined in Uie laboratory. Tliis is a large increase over the number 

 received the previous year (1,;)81 ), and a slight increase in the number 

 examined (1,961). The stomachs examined this year may l>e grouped 

 as follows: 



Sparrows 713 



Swallows . .... ... 323 



Woodpeckers 318 



Blackbirds IHO 



Flycatchers 142 



Gxills .- . 76 Total _ 1,989 



Nearly 50 per cent of these stomachs were those of sparrows and 

 blackbirds, used in the completion of reports on these two groups, 

 and nearly 25 per cent those of swallows and flycatchers, for investi- 

 gations now well under way. Thus far 672 swallows' and 1,0;^0 fly- 

 catchers' stomachs have been examined, and it is hoped that enough 

 material may be collected in the near future to permit publication 

 of at least a preliminary report on the food of these important birds. 

 Some progress has also been made in other groups ; 600 or 700 stomachs 

 of thrushes and about 150 of titmice have been examined preparatory 

 to issuing reports on these l)irds. The bulletin on native sparrows 

 has beendelayed in order to include interesting and vahiable matter 

 concerning the food of nestlings, methods of feediug, and results of 

 experiments with captive birds. This report will probaljly appear in 

 the near future. More than 300 woodpeckers' stomachs were examined, 

 with a view to preparing a revised edition of Bulletin No. 7, on the 

 "Food of woodpeckers," which has been out of print for some time, 

 but which is still in demand. 



The unusual attention which certain plume birds, notably grebes 

 and gulls, attracted during the year suggested an investigation as to 

 whether these species eat food fish to any extent. The stomachs of only 

 40 grebes and 76 gulls were available for examination, material too 

 meager to furnish conclusive results, bnt interesting as showing the 

 general character of the food. The grebes' stomachs neai-ly all con- 

 tained feathers in greater or less quantities and very few if any fish. In 

 fact, the fish element was largely exceeded by that of aquatic insects. 

 The gulls selected were all Franklin's gull {Larus franMini), a species 

 which breeds in the Upper Mississippi Valley, and hence is likely to be 

 of some economic importance. These birds fed to a very slight extent 

 on fish during the breeding season, but destroyed a remarkable num- 

 ber of insects, as shown by two stomachs collected at Harrison, S. Dak. 

 One of these stomachs contained 83 beetles, chiefly predaceous, 87 

 bngs, 984 ants, a tree cricket, a grasshopper, and 2 spiders; the other, 

 16 weevils, 66 crickets, 34 grasshoppers, and several other insects. 

 Many gulls are important as scavengers, and the economic i^osition of 

 these and other birds which are killed for millinery purposes, as well 

 as of game birds of various kinds, should be more definitely known, 

 in order that intelligent control of their destruction may be exercised. 

 The material illustrating the food of these species is deficient; bnt if 

 sportsmen and ornithologists would take the trouble to send us the 

 stomachs of a few of the birds which they kill each year, this deficiency 

 would soon be remedied, and the Division would be able to i)resent 

 results which would be of general interest. Birds' stomaclis may be 

 collected with little trouble, and blanks and directions for preserving 

 them may be had upon api)lication. 



