EFFECT UPON HEALTH OF MAN 53 



the robin. Although originally a forest thrush, 

 it came into the open fields after the early set- 

 tlers had cleared the land, and it found there a 

 more suitable home than the deep forest. Once 

 established in the clearings, the robin increased 

 in such numbers that it now holds the record 

 for all land birds. Civilization for it has proved 

 a boon. 



Following not far behind the robin is the 

 alien English sparrow, which at its present rate 

 of propagation will some day not far off head the 

 list. Then in the order named come the catbird, 

 brown thrasher, house wren, kingbird, and blue- 

 bird. The crow stands well up on the list, but 

 raptorial birds, long victims of human miscon- 

 ception, are down near the end, a lowly posi- 

 tion into which gun and trap have forced 

 them. 



2 

 Their Destruction of Insects Obnoxious to Man 



In agriculture the economic value of birds is 

 based entirely upon the requirements of their 

 stomachs. The same condition holds true for 

 the birds who make our barns and roofs their 

 home. One seldom pauses to deliberate upon 

 the causes which led the nighthawks and the 

 swallows to swoop and streak an erratic course 

 through the air above the barn-yard or pasture. 



