INTRODUCTION. 17 



It will be seen from the above that of the rapacious birds with which 

 our country is so well furnished, there are but few which deserve 

 to be put on the black list and pursued without mercy. The greater 

 number either pass their whole lives in the constant performance of 

 acts of direct benefit to man or else more than make good the harm 

 they do in the destruction of insectivorous birds and poultry by 

 destroying a much greater number of animals well known to be hostile 

 to the farmer. 



The birds of prey are all peculiarly fitted by nature to play their 

 parts in the maintenance of the balance in the animal world. Possessed 

 of amazingly acute eyesight, strong bills for tearing their prey, sharp 

 talons that lock with a never-failing clutch and insure the speedy death 

 of a victim by piercing its very entrails, added to ample and enduring 

 powers of wing, they must be admitted to be well equipped for their 

 occupation. They are all great eaters, and when the supply of food 

 is unlimited are gorged during most of the time. Their digestion is 

 very rapid and their assimilation perfect; consequently the amount 

 of food a bird consumes each day in relation to its own weight is very 

 great. It is well that it is so, for the habit of taking more food than is 

 necessary for their immediate needs enables them to store up force for 

 future emergencies and preeminently fits them for the work of keeping 

 nature's balance true. They*are required at times, from inclement 

 weather or other causes, to withstand great exposure and long pro- 

 tracted fasts, which they do with little inconvenience. 



In the case of the birds of prey, as in some of the other orders, the indi- 

 gestible portions of food, such as feathers, hair, bones, and the hard 

 coverings of insects, are formed into balls by the movements of the 

 stomach, after the nutritious portions have been absorbed. These 

 masses, which are known as i pellets,' are regurgitated from the stom- 

 ach before a new supply of food is taken. The movements of the stom- 

 ach so shape these 'pellets' that every sharp piece of bone or hard 

 material which might otherwise injure the mucous membrane is care- 

 fully enveloped by a felty covering of hair or feathers. In the case of 

 some of the owls which have regular roosting places vast numbers of 

 these pellets collect, and an examination of them will give a perfect in- 

 dex to the character of the food devoured. 



No less than 2,690 stomachs have been examined in the preparation 

 of this bulletin, and the contents are enumerated in the tables accom- 

 panying the species. Of these, 169 contained the remains of poultry and 

 game birds; 463, of other birds; 966, of mice; 397, of other mammals; 

 and 623, of insects. If the stomachs of the six species which feed very 

 largely upon game and poultry are eliminated we have a total of 2,212 

 stomachs. Of these 78, or 3 J per cent, contained the remains of poultry 

 or game; 257, or 11 per cent, of other birds; 945, or 42 J per cent, of 

 mice; 309, or 14 per cent, of other mammals; and 599, or 27 per cent, 

 of insects. 



7626— No. 3 2 



