The bark of trees also forms a favorite shelter for numerous insects, and 

 behold the wrens, nuthatches, warblers, and creepers, with sharj^est of eyes and 

 slenderest of bills, to detect our foes and to dislodge them from crack and cranny. 



The air is full of flying insects, and to take care of these there are the 

 swallows, swifts, and night-hawks, whose wings and bodies are so shaped as 

 to endow them with the speed and agility necessary to follow all the turns and 

 windings of their nimble insect prey. 



The whippoorwills. swift of wing and with capacious mouths beset with 

 bristles, attend to the night-flying insects when most birds are asleep, while the 

 hawks by day and the owls by night supplement the work of other birds and 

 have a special function of their own, the destruction of noxious rodents. 



Thus every family of birds plays its own part in the warfare against insects 

 and other foes to man's industry, and contributes its share to man's welfare. 



Birds would fall far short of what they accomplish for man were they not 

 the most active of living things. It is curious that the group of vertebrates which 

 live the fastest — that is, have a higher temperature and a more rapid circulation 

 than any other — should be related by descent to a family of such cold-blooded 

 creatures as the reptiles and lizards, which often go without food and hibernate 

 for considerable periods. Very different is it with birds. Few realize the en- 

 ormous quantity of food required to sustain the energy of these creatures, most 

 of whose waking hours are spent in a never-ending search for food. 



In satisfying their own hunger birds perform an important service to man, 

 for notwithstanding the fact that the acreage under cultivation in the United 

 States is larger than ever before, and that the crops are greater, the cost of 

 foodstuffs continually mounts upward. Meanwhile the destruction of farm and 

 orchard crops by insects and by rodents amounts to many millions each year, 

 and if any part of this loss can be prevented it will be so much clear gain. 



The protection of insectivorous and rodent-destroying birds is one of the 

 most effective means of preventing much of this unnecessary loss, and the public 

 is rapidly awakening to the importance of this form of conservation. From the 

 farmers' standpoint, such birds as the bobwhite, prairie-chicken, the upland 

 plover, and the other shore birds are worth very much more as insect eaters 

 than as food or as objects of pursuit by the sportsman. This statement applies 

 with especial force to such species as the prairie-chicken, which everywhere in 

 its old haunts is threatened with extinction. 



The value of birds to the farmer is plain enough, but we do not usually 

 think of birds as having any direct relation to the public health. To prove that 

 they do, however, it is only necessary to state that 500 mosquitoes have been 

 found in the stomach of a single night-hawk ; th;it in a killdeer's stomach 

 hundreds of the larvse of the salt-marsh mosquito have been found, and that 

 many shore birds greedily devour mosquito larvae. As mosquitoes are known to 

 carry the germs of such serious diseases as dengiie fever and malaria, it is 

 evident that by destroying them birds are conferring an important benefit on 

 man. It may be added that not infrequently ticks are eaten by birds, and that 

 the tick responsible for the spread of Texas fever among cattle has been found 

 in the stomach of the bobwhite. 



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