BIRDS EAT INSECTS 



547 



the tide of civilization advances, their numbers are slowly but 

 surely decreasing, so that as important factors in man's welfare 

 they may be considered almost negligible. 



Practical Exercises 26. What harm is done in your locality by any of the 

 above-mentioned animals ? How can cats be kept from killing birds ? Give 

 all the reasons you can for and against keeping cats. What agencies control 

 the harmful animals in your state ? 



Self-Testing Exercise 



Many oysters are destroyed annually by (1). Rats 



destroy thousands of dollars' worth of (2) for (3) 



every year. Many fishes are killed by (4) (5), 



(6), and (7) (8). Animals that are known 



to attack men are the (9), (10), (11), and 



(12). 



PROBLEM VI. WHAT IS 



THE ECONOMIC IMPORTANCE OF 

 BIRDS? 



Birds eat insects. The food of birds . makes them of great 

 importance to agriculture in our country. A large part of the diet 



L. W. Brownell 



If birds cannot get insects they eat grains. Some birds seem to prefer insects to seeds. 

 Here is the remains of an ear of corn after Here is a young thrasher receiving a cater- 

 a crow has eaten. pillar. 



