52 THE SCOTTISH NATURALIST 



from ethical and aesthetical reasons, as birds give beauty 

 and animation to Nature. We also wish to preserve their 

 species, and hence the protection of birds signifies the 

 preservation of the monuments of Nature." 



As I have elsewhere stated, " the wholesale destruction 

 of birds for the purpose of protecting crops and orchards is, 

 economically, an unsound policy," but the bird-lover is 

 equally wrong in his or her sentimental enthusiasm, and 

 the argument quoted above might quite logically be 

 advanced for the rat, the mosquito, and numerous other 

 obnoxious animals. 



In any investigation of such a subject as this, if the 

 results are to be of any value, we must place on one side 

 all sentimental considerations and be guided solely by the 

 conclusions obtained by careful and detailed work extending 

 over a considerable period of time. 



Much of the earlier work carried out in this country is 

 very crude ; further, many opinions are annually expressed 

 in the Press founded upon insufficient knowledge. The 

 economic status of any particular species of bird can only 

 be ascertained after prolonged and careful investigation 

 by trained and experienced investigators. The setting of 

 senior students in our agricultural colleges and universities 

 to undertake such investigations is hardly likely to further 

 our knowledge ; on the other hand, with the semblance of 

 authority, it is very likely to prove misleading. 



Bearing in mind the many difficulties that confront the 

 investigator, experience has shown that a very accurate 

 knowledge may be gained of a bird's feeding habits and 

 the nature of its food by the employment of the following 

 methods. 



Firstly, it is necessary to examine the food contents 

 found in the whole of the intestinal tract frequently, during 

 the different seasons of the year. The nature of these and 

 their bulk must be accurately identified. The nature o f the 

 food brought to the nest by the parents during the breeding 

 season must also be taken into account. " Any investigation 

 on the economic status of most species of wild birds is 

 incomplete, and to a large extent misleading, that does 



