162 BIOLOGICAL PROBLEMS 



worms, and slugs that are known to be injurious to 

 the food crops in one group, and those that, by them- 

 selves destroying animal pests, are known to be bene- 

 ficial. In like manner the vegetable food was divided 

 into the seeds, leaves, and other fragments of food 

 plants which were placed in one group, and those 

 of pernicious weeds in another. I may remark that 

 this part of the work required the co-operation of 

 skilled entomologists and botanists, for it needs special 

 knowledge to determine whether a fragment of an 

 insect a leg or a wing belong to a beneficial or to 

 an injurious insect, and to be quite certain that the 

 small seeds found, particularly in the crops of chaf- 

 finches, belong to pernicious weeds or to useful grasses 

 and food plants. 



As a general result of these investigations it was 

 agreed that, on balance, the starlings are beneficial 

 to the farmer. It is true that they take some toll of 

 grain ; but it must be borne in mind that a great deal 

 of this grain, being scattered in fields or around barns, 

 would never be recovered for the farmer. On the 

 other hand, they destroy so many insect pests, and 

 possibly keep in check so many weeds, that they pay 

 and more than pay for the grain food that they 

 consume. 



As a result of these investigations it may also 

 be said that the chaffinch is a beneficial bird, as is 

 shown in the following statement, the result of many 

 years' accurate and laborious work, for which I am 

 indebted to Mr. H. S. Leigh of the Manchester Uni- 

 versity :- 



"By far the greater part of the vegetable food of 

 the chaffinch consists of the seeds of weeds, the seeds 

 of chickweed, knot-grass, and dock being in greatest 

 abundance. Seeds of chickweed were found in almost 

 every specimen from September to March. Seeds 



