Vol. XIX, No. 2 



WASHINGTON 



February, 1908 



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THE POLICEMEN OF THE AIR 



An Account of the Biological Survey of the Department 



of Agriculture 



By Henry Wetherbee Henshaw 



THE pursuit of science solely for 

 its own sake, however commend- 

 able it may be, is not the spirit 

 that animates our government in its 

 support of scientific research. In its aims 

 and ambitions this is a practical age. 

 Thousands of men are experimenting, in- 

 venting, and prying into the secrets of 

 nature for the avowed purpose of utiliz- 

 ing their discoveries for the practical 

 benefit of mankind. Applied science has 

 come to occupy a very important place in 

 our government institutions, and in none 

 is it more important than in the Depart- 

 ment of Agriculture. 



From small beginnings, the department 

 in little less than half a century has ex- 

 panded in every direction, and in the last 

 decade, under the able management of 

 Secretary Wilson, has grown to huge pro- 

 portions. Its work is divided among 

 numerous bureaus, each with a distinct 

 line of research, and a small army of as- 

 sistants is employed, many of whom are 

 engaged in various fields of scientific in- 

 vestigation for the benefit of the Ameri- 

 can farmer. 



It is the work of one of its bureaus, the 

 Biological Survey, that concerns us here. 

 The Survey had its beginning in 1885, 



when its present head, Doctor C. Hart 

 Merriam, with one assistant, began to in- 

 vestigate the economic relations of birds 

 to agriculture. The scope of the field was 

 soon enlarged to include the kindred sub- 

 ject of economic mammalogy. In addi- 

 tion to these important subjects, its duties 

 now include the study of the geographic 

 distribution of animals and plants with 

 special reference to the determination of 

 life and crop zones, and the supervision 

 of matters relating to game protection 

 and the importation of foreign birds and 

 animals. 



1 



RELATION OE BIRDS TO AGRICULTURE 



When the Survey began its work very 

 few accurate observations on the food of 

 birds had been recorded. Most of the 

 published information bearing on the sub- 

 ject rested on field observation only, and, 

 besides the liability to error from faulty 

 or insufficient observations, the data 

 gathered in this way were entirely inade- 

 quate. It is not enough to be told that 

 birds feed on insects ; we must know the 

 particular kinds they eat. The fact that 

 the crow sometimes eats corn is not suffi- 

 cient evidence upon which to condemn 



