126 NATURE-STUDY 



Thus we can say that the goshawk, the sharp-shinned 

 hawk, and Cooper's hawk do more harm than good, but 

 that the other hawks arc on the whole beneficial in destroy- 

 ing harmful field vermin ; that the great horned owl is about 

 as useful in destroying field mice, rats, gophers, moles, frogs, 

 etc., as he is harmful in steahng chickens and in kiUing quail, 

 grouse, and song birds; and that the bluejay is not such 

 a thief and cannibal as he is generally thought to be. Most 

 bird students agree that the English sparrow has proved a 

 curse instead of blessing to this country. He does not pay 

 for the grain he eats, nor for the beneficial birds he drives 

 away, nor for the general nuisance he makes of himself 

 around our houses. 



We know that the woodpeckers and warblers keep our 

 trees free from borers, caterpillars, plant lice, etc. ; and that 

 cuckoos and flycatchers, meadow larks, orioles, swallows, 

 wrens, robins, and bluebirds are almost wholly beneficial. 

 They feed almost entirely upon injurious insects and worms. 

 We know that the wild sparrows, such as the song, chipping, 

 tree, field, and other sparrows, and the slate-colored junco 

 are very useful in eating great quantities of weed and grass 

 seeds. Professor Beal estimates^ that in Iowa alone the 

 single species of the tree sparrow destroys at least 875 tons 

 of weed seed. And Mr. Judd estimates^ that the bob whites 

 in the State of Virginia annually destroy 573 tons of weed 

 seeds. This gives a good idea of the usefulness of some of 

 our birds. 



Birds are the natural check upon the too great multiphca- 

 tion of insects. The thrush family, the wren family, swal- 



^ " Common Birds in Relation to Agriculture," Farmer's Bulletin, No. 54. 

 ^Yearbook, 1903. U. S. Department of Agriculture. 



