24 BIRDS IN THEIR RELATIONS TO MAN. 



ness for the sap and inner bark of trees. Of the forty or fifty 

 bh'ds, exclusive of hawks and owls, thus far investigated, the 

 English sparrow is the only one which has been condemned. 



"investigations regarding beneficial birds. 



" A number of species usually considered beneficial have 

 also received attention. The Baltimore oriole, the meadow- 

 lark, red-winged blackbird, rose-breasted grosbeak, cedar- 

 bird, robin, bluebird, swallows, and several flycatchers have 

 been studied by Professor Beal, and the shrikes, cat-bird, 

 mocking-bird, brown thrasher, and house wren by Dr. Syl- 

 vester D. Judd. One of the interesting facts brought out in 

 studying the cat-bird was the discovery that some birds prefer 

 wild to cultivated fruits, so that the latter may be protected 

 by planting certain berry-bearing slirubs and trees, especially 

 in regions where wild fruit is naturally scarce. The king- 

 bird, frequently condemned as a destroyer of honey-bees, was 

 shown to eat very few bees, and these mostly drones. On 

 the other hand, it kills many of the destructive robber flies, 

 and a large proportion of its food is made up of destructive 

 insects, so that it must be regarded as decidedly beneficial. 

 Recent investigations show less favorable results in the case 

 of some other flycatchers, and indicate that the prevailing 

 idea that all insectivorous birds are necessarily beneficial 

 may re([uire decided modification, and that there are birds 

 which habitually feed on beneficial insects to such an extent 

 as to lower their value to the farmer, if not to place them 

 among the enemies of his crops. 



" results of fourteen years' work. 



"As a result of fourteen years' work, the Biological Survey 

 has brought together a collection of about thirty-two thousand 

 bird stomachs, of which some fourteen thousand have been 

 examined. It has investigated about one hundred species 

 (nearly half hawks and owls) and |)re[>are(] Hie results for 



