224 



Nature-Study Agriculture 



San Diego Society Nat. Hist. 



FIG. 175. A pocket gopher; a destructive burrowing animal that is held 

 in check by owls. 



the birds that live on seeds help him to keep his farm 

 free from weeds. The crop of a pheasant was found to 

 contain eight thousand chickweed seeds and a dandelion 

 head. The sparrows (Fig. 177), of which there are so 

 many kinds, are especially useful in destroying weed 

 seeds. These little birds may often be seen clinging to 

 a tall weed, picking at the ripening seeds. It has been 



estimated that each 

 sparrow eats as much 

 as a fourth of an 

 ounce of seed a day, 

 and that in one year 

 all of the sparrows in 

 a state like Iowa must 

 eat about eight hun- 

 dred and seventy-five 



Son Diego Society Nat. Hist, tons of Seed which 



FIG. 176^ Head, tail (under side), and foot of might Otherwise make 

 gnatcatcher ; a good example of an insect-eating 



bird. a troublesome crop of 



