306 FARM AND SCHOOL PROBLEMS. 



"As many as 1,000 grasshoppers have been found in the 

 stomach of a Swainson's hawk, representing a single meal; and 

 in the retreat of a pair of barn owls have been found more than 

 3,000 skulls, 97 per cent of which were of mammals, the bulk 

 consisting of field mice, house mice, and common rats. Nearly 

 half a bushel of the remains of pocket gophers animals which 

 are very destructive in certain parts of the U. S. was found near 

 a nest of this species." 



It has been estimated that a family of Bob-whites consisting 

 of two adult .birds and ten young, would consume 780,915 insects 

 and 59,707,888 weed seeds in a year in addition to their other food. 



A Bob-white in captivity has been known to consume at one 

 meal 100 chinch bugs, 12 squash bugs, 2,326 plant-lice, 39 grass- 

 hoppers, 12 cut worms, 12 army worms, 568 mosquitos, 101 

 potato beetles, and 8 white grubs. 



The following record is taken from another list given in the 

 National Audubon Societies' leaflets : 5,000 chrysanthemum black 

 flies, 1,350 flies, 1,286 rose-slugs, 1,300 grasshoppers, 932 mis- 

 cellaneous insects, eaten by a Bob-white in one day. 



PROBLEMS. 



1. It has been estimated that there are approximately 2000 birds per 

 sq. mi. in the U. S. ; at that rate what would be the total number in the 

 U. S.? 



2. At the rate of 2000 birds per sq. mi., how many would this be per 

 80-acre farm? 



3. If the average number of large insects killed per bird is estimated 

 at 50 per day, how many insects does the average bird kill per year 

 (365 days) ? 



4. Estimating that on an average the quantity of insects killed an- 

 nually by each bird will fill a peck measure, how many bushels of insects 

 are destroyed annually by birds in the U. S. ? 



5. How does the number of bushels of insects destroyed compare 

 with the total number of bushels of corn, wheat, oats and clover seed pro- 

 duced in 1914? 



6. If each bushel of insects destroyed would have damaged crops to 

 the extern; of 50c, what did the birds save to agriculture in one year In 

 theU. S.? 



