170 



ANIMAL BIOLOGY 



garden are the only ones that lose a noticeable amount of 

 food. We cut down the forests from which the birds ob- 

 tain part of their food. We destroy insect pests at great 

 cost of spraying, etc. The commission the birds charge 

 for such work is very small indeed. (See pages 177-183.) 



FIG. 314. WOOD DUCK, male (Aix sponsa). Nests in hollow trees throughout 

 North America. Also called summer duck in South. Why ? 



The English sparrow is one bird of which no good word 

 may be said. Among birds, it holds the place held by rats 

 among beasts. It is crafty, quarrelsome, thieving, and a 

 nuisance. It was imported in 1852 to eat moths. The 

 results show how ignorant we are of animal life, and how 

 slow we should be to tamper with the arrangements of 

 nature. In Southern cities it produces five or six broods 

 each year with four to six young in each brood. (Notice 

 what it feeds its young.) It fights, competes with and 

 drives away our native useful birds. It also eats grain and 

 preys upon gardens. They have multiplied more in Aus- 



