VALUE OF BIRDS TO FARMERS 29 



THE VALUE OF BIRDS TO FARMERS 



29. Mr. Beal, of the United States Biological Survey, once 

 estimated that the tree sparrow in a single season in the 

 state of Iowa ate 1,750,000 Ib. of weed seed. 



Mr. Chester A. Reed, of Massachusetts, estimates that on 

 an average each bird will eat daily for about five months in 

 the year, from May to September inclusive, 100 harmful 

 insects. He also estimates 120,000 insects to the bushel. 



EXERCISE 



1. If 15 Ib. of weed seed will sow 1 A., how many acres 

 of weeds would the seed eaten by the tree sparrow in Iowa 

 alone have sown ? At 650 an acre for cutting, raking, and 

 burning the weeds, what would it have cost the farmers of 

 Iowa to destroy the weeds ? 



2. Counting 5 insect-eating birds to the acre, how many 

 bushels of harmful insects will the birds on an average-sized 

 farm in your community destroy during 5 mo. ? 



3. How many cutworms, grubs, and harmful insects will 

 be destroyed by a flock of 50 birds that follow the plow 

 daily for 2wk.? 



4. If 2 out of every 100 insects and worms destroyed are 

 either cutworms or grubs (these are the destroyers of young 

 corn), and if both the grubworm and the cutworm destroy 

 on an average 3 corn plants daily, what is the value of the 

 50 birds following the plow for 2 wk., when corn is 500 per 

 bushel ? (Allow one good ear to each plant destroyed.) 



5. If a quail, in the course of a year, eats 250 worth of 

 grain, and destroys $2 worth of harmful insects and weed 

 seed, how much has a farmer injured himself by killing 

 3 pairs of quails if a pair raise a brood of 12 each year ? 



