Wyoming Birds. 



all parts of the country. The eagles are also decreasing in 

 numbers, probably because gunners are too likely to shoot 

 when the opportunity comes. These birds are also fre- 

 quently caught in traps set for coyotes and other animals. 



THE ECONOMIC VALUE OE BIRDS. 



It is well known that birds are among the most important 

 factors in checking the damage done by insects to agricul- 

 tural crops. It is an established fact that insects became 

 terrible pests in Australia shortly after the wholesale de- 

 struction of the birds from eating poisoned grain intended 

 for rabbits. Certain families of birds feed almost exclu- 

 sively upon insects. Certain other families are efficient 

 agents for destroying weed seeds. The Sparrows, Horned 

 Larks, and Finches, and in fact all birds which have a 

 short, thick, conical bill, are mainly seed eaters. 



THE AMOUNT OF EOOD CONSUMED BY BIRDS. 



One is likely to suppose that the birds can not be of any 

 great economic importance because they are small and in- 

 significant in appearance. Before deciding upon this point 

 it might be well to consider that they occur in enormous 

 numbers and eat amounts altogether out of proportion to 

 their size, when judged from our standards. Digestion 

 goes on very rapidly in these warm-blooded, active animals, 

 and so they eat almost constantly. In cases investigated, it 

 has been shown that food passes entirely through the diges- 

 tive tract in the course of an hour or an hour and a half. 

 Birds frequently eat the equivalent of eight full meals per 

 day and consume approximately their own weight of food. 

 This is true more especially of young birds, which in 

 a few cases investigated have been shown to swallow 

 more than their own weight of food and increase from 

 twenty to forty per cent in weight daily. Some one has 



