Man and Nature 391 



a bureau of the Department of Agriculture some twenty years 

 later. This bureau has contributed more to our knowledge, 

 both scientific and economic, of tiie birds and maimiials of 

 North America than any other agency. We cannot in so 

 brief a compass do justice to its work, but a bird's eye glance 

 at it may be of interest. At the outset it nuist be admitted 

 that, like a lusty youngster, the Bureau has fre(iuently out- 

 grown its clothes, and frequently also has it wandered far 

 from its parental home. In how far the hair-splitting re- 

 finements in the classification of birds and mammals in wliich 

 it has often indulged itself may be of value either to science 

 or agriculture is open to question, but there can be no ques- 

 tion of the value l)oth to science and agriculture of the great 

 bulk of its work. The vast amount of data which it has 

 gathered relative to the classification and distribution of 

 North American birds and mammals are indispensable to 

 any study of the influence of environment upon their evolu- 

 tion and spread, wliile its studies on the migration of birds 

 have furnished invaluable data not oidy for the study of the 

 causes of this as yet inexplicable phenomenon, but also for 

 the formulation of laws for their protection. 



Prior to the establishment of the Bureau our knowledge 

 of the food habits of birds was the result of a few sporadi( 

 investigations. Since its inception it has conducted a sys- 

 tematic study of this question, including the examination ot 

 some 80,000 stomachs of many species of birds, as a result of 

 which we now have very definite information regarding the 

 economic value of most of our wild birds, and can pursue a 

 rational program for their protection. I\Tany instances of 

 the value of birds to the farmer which have been sliown by 

 these investigations could be cited, in addition to those al- 

 ready given of the food habits of hawks and owls. One of 

 the worst foes of the horticulturist, especially the fruit grower 

 of California, is the scale insect. This, as its name implies, 

 is a tiny scale-like creature of no resemblance externally to 

 an insect, but containing evidence of its relationshi]i in its 

 internal structure and its development. I have no data rela- 

 tive to losses from scale insects, but an estimate of a cost of 

 10 to 25 cents a tree as a protective tax against the San Jose 

 scale, gives some idea of the burden they put upon the fruit 

 grower. We shall have more to say regarding Ihese insects 

 later on, but for the present we note that the Bureau has 

 shown, what was formerly unknown, that many species of 

 birds prey upon them, while of some species they form the 

 favorite food. 



The habitue of field and fon^tst, who seeks his favorite haunts 

 after the first snow fall of the winter, is likely to encounter 



