THE ECONOMIC STATUS OF WILD BIRDS 53 



not deal" with this important matter, "for during the 

 nesting period the food of the parent birds consists largely 

 of insects, slugs, spiders, and worms, and that of the young 

 almost entirely so, and the amount of the food consumed is 

 greater than at any other season of the year." 



Secondly, the nature of the faeces, and also of the faecal 

 matter extruded from the nest, must receive attention. 



Thirdly, the rate of digestion of different kinds of food 

 and in different species of birds is another important 

 factor. 



Finally, it is all-important that we should have careful 

 observations made in the field. 



If the collection of this information extend over the 

 whole of the months of the year and for successive years, 

 and the birds examined be received from many localities 

 in a given district or series of districts, and provided that 

 sufficient care be exercised in the identification of the food 

 materials and their percentages, then I believe that it is 

 possible to arrive at a fairly correct answer to the question, 

 " Is this or that particular species of bird beneficial, neutral, 

 or injurious ? " 



With regard to these methods, I should like to add a 

 few comments. The examination of the food contents of 

 the intestinal tract is frequently misleading if it cover only 

 a portion of the year or any particular season, for there are 

 species that would appear to be distinctly injurious if the 

 verdict has to be pronounced upon the food consumed by 

 them during the months of July, August, and September, 

 but when the nature of the food for the remaining nine 

 months of the year is also considered a very different 

 result is obtained. 



Hitherto it has been the custom to examine the contents 

 of the crop (where present) and stomach, but this is not 

 enough, for in many species of birds, weed seeds and other 

 matter of an indigestible nature pass into the intestine and 

 are not accounted for unless the whole of the intestinal 

 tract is opened and the contents washed out and examined. 



In a like manner very valuable results are obtainable 

 from a proper examination of the faeces. 



