ECONOMIC RELATIONS OF OUR BIRDS. 
il2 
mediately, I preferred to retain the manuscript until the latest possible date in 
order to retouch it as might seem desirable. This has been done so far as prac¬ 
ticable. The valuable results obtained by Prof. S. A. Forbes in regard to the 
food of birds of Illinois has been included, and the whole nomenclature has been 
made to conform with Dr. Coues’ new “ Check List of North American Birds.” 
Following my own notes on the food of each species examined, there have 
been given such other api>arently authentic records of food as could be obtained. 
This suppl-ernentary inforxnation is far from being as complete as I had hoped to 
make it, and I fear not so accurately transferred as it should have been, for it 
has been impracticable to compare the transcript with the originals. I regret 
this the more, since the items were jotted down during the odd moments which 
feu between other absorbing duties. 
The amount of specific information which it has been possible to present in 
regard to the food of our birds may seem unduly small compared with the 
amount of material which has been examined. Larger results might have 
been obtained had the materials, after having been classified in a general 
way, been subjected to a careful examination by entomologists expert in the 
various departments. Birds rarely swallow an insect of any size without tak¬ 
ing especial care to severely mutilate it first, and I have no doubt that the bird 
has, in his own mind, the best of reasons for doing so. One may easily imagine 
the commotion which might come of introducing an able-bodied ground-beetle 
or a centipede grown expert in elbowing his way through aU sorts of tortuous 
and impassable galleries. It is this fragmentary character of the food which 
has made it so difficult to classify the insects which had been eaten by the birds 
obtained. But had it been possible to identify specifically the 7,663 insects, etc., 
taken from the stomachs of the 1,608 birds, this would have been by far the 
smallest part of the task set, for then it would be required to command a full 
and broad knowledge of the economic relations of the insects eaten. But with 
this difficulty solved we must recognize still another of greater magnitude and 
higher degree. 
Because of these great difficulties inherent in the task itself, and the ample 
grounds they present for difference of opinion in regal’d to final conclusions, it 
has seemed very desirable that there should be presented some of those general 
considerations which have served as guides to the classification adopted. These 
considerations are presented as an introduction to the body of the report. 
There remains now the pleasant duty of thanking you for the privilege of 
having struggled with a difficult task, and, while the hopes you have enter¬ 
tained may find in this report but a faint realization, it is trusted that en(^ugh 
of real value may be found in it to repay the labor devoted to its preparation. 
Very respectfully yours, 
F. H. King. 
INTRODUCTION. 
The discordant views held by prominent ornithologists and entomologists, in 
regard to the value of birds as insect destroyers, and particularly in regard to 
the actual and comparative value of certain species, prove conclusively that 
some of them have reached their conclusions on insufficient or false data. For 
this reason, and because it appears that many more facts must be gleaned and 
collated before final conclusions in regard to the economic value of birds can be 
reached, it is deemed advisable to consider briefly, as introductory to what fol¬ 
lows, some of the more important factors which should enter into the solution 
of the problems of economic ornithology. 
