Ab a rule birds do not live very long, but they live fast. They breathe rapidly 

 and have a higher temperature and a more rapid circulation than other vertebrates. 

 This is a fortunate circumstance, since to generate the requisite force to sustain their 

 active bodies a large quantity of food is necessary, and as a matter of fact birds have 

 to devote most of their waking hours to obtaining insects, seeds, berries, and other 

 kinds of food. The activity of birds in the pursuit of insects is still further stimulated 

 by the fact that the young of most species, even those which are by no means strictly 

 insectivorous, require great quantities of animal food in the early weeks of existence, 

 80 that during the summer months — the flood time of insect life — birds are compelled 

 to redouble their attacks on our Insect foes to satisfy the wants of their clamorous 

 young. 



Field observations of the food habits of birds serve a useful purpose, but they are 

 rarely accurate enough to be fully reliable. The presence of certain birds in a com 

 or wheat field or in an orchard is by no means proof, as is too often assiuned, that they 

 are devastating the grain or fruit. They may have been attracted by insects which, 

 unknown to the farmer or orchardist, are fast ruining his crop. Hence it has been 

 foiind necessary to examine the stomachs and crops of birds to ascertain definitely 

 what and how much they eat. The Biological Survey has in this way examined 

 upward of 50,000 birds, most of which have been obtained during the last 25 years 

 from scientific collectors, for our birds are too useful to be sacrificed when it can 

 possibly be avoided, even for the sake of obtaining data upon which to base legis- 

 lation for their protection. 



It is interesting to observe that himgry birds — and birds are hungry most of the 

 time — are not content to fill their stomachs with insects or seeds, but after the stom- 

 ach is stuffed until it will hold no more continue to eat till the crop or gullet also is 

 crammed. It is often the case that when the stomach is opened and the contents piled 

 up the pile is two or three times as large as the stomach was when filled. Birds may 

 truly be said to have healthy appetites. To show tlie astonishing capacity of birds' 

 stomachs and to reveal the extent to which man is indebted to birds for the de- 

 struction of noxious insects, the following facts are given as learned by stomach 

 examinations made by assistants of the Biological Survey: 



A tree swallow's stomach was found to contain 40 entire chinch bugs and fragments 

 of many others, besides 10 other species of insects. A bank swallow in Texas devoured 

 68 cotton-boll weevils, one of the worst insect pests that ever invaded the United 

 States; and 35 cliff swallows had taken an average of 18 boll weevils each. Two 

 stomachs of pine siskins from Haywards, Cal., contained 1,900 black olive scales and 

 300 plant lice. A killdeer's stomach taken in November in Texas contained over 

 300 mosquito larvae. A flicker's stomach held 28 white grubs. A nighthawk's 

 stomach collected in Kentucky contained 34 May beetles, the adult form of white 

 grubs. Another nighthawk from New York had eaten 24 clover-leaf weevils and 375 

 ants. Still another nighthawk had eaten 340 grasshoppers, 52 bugs, 3 beetles, 2 

 wasps, and a spider. A boat-tailed grackle from Texas had eaten at one meal about 

 100 cotton boUworms, besides a few other insects. A ring-necked pheasant's crop 

 from Washington contained 8,000 seeds of chickweed and a dandelion head. More 

 than 72,000 seeds have been found in a single duck stomach taken in Louisiana in 

 February. 



A knowledge of his bird friends and enemies, therefore, is doubly important to the 

 farmer and orchardist in order that he may protect the kinds that earn protection by 

 their services and may drive away or destroy the others. At the present time many 

 kinds of useful birds need direct intervention in their behalf as never before. The 

 encroachments of civilization on timbered tracts and the methods of modem intensive 

 cultivation by destroying or restricting breeding grounds of birds tend to diminish 

 their ranks. The number of insect pests, on the other hand, is all the time increasing 

 by leaps and bounds through importations from abroad and by migration from adjoin- 



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