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tence it usually comes to pass that a healthy balance is maintained 
on the principle of the survival of the fittest. 
We do not have to be reminded however that in the problems 
before us there is no longer a natural or free “ struggle for exis- 
tence,’’ since man and his methods have so obtruded themselves 
upon the scene as to greatly disturb the balance so easily recog- 
nized in wild nature. No single factor within the entire history 
of life has so disturbed the natural course of balance and adjust- 
ment as man,—this forest destroying, soil ravishing, bloodthirsty, 
or sport-craving maniac, so-called “ civilized ” man. 
It is therefore under conditions associated with this changed 
condition of things that our problems become such. And here 
they receive their significance and importance in the bearing they 
come to have on man’s conceptions of economy. It is moreover 
under the altruistic and humanistic spirit which has come to 
fruition in these later times and which looks both forward and 
backward as well as downward, recognizes an obligation and 
righteousness and equity in the constitution of nature, that these 
with kindred problems have come to their rightful recognition. 
The present method of investigation is so far as I now recall 
due to the scientific spirit and aim of Prof. S. A. Forbes, of the 
Illinois State Laboratory of Natural History, from which in other 
lines as well, have come many of the best products of such inves- 
tigations. 
It consists essentially in a critical investigation and deter- 
mination of the food contents of the stomachs of birds in suffi- 
cient numbers and seasons to warrant an inference as to their 
actual and average food proclivities. 
A second method and one not without its advantages, 
though lacking to some extent in the elements of exactness char- 
acteristic of the former is that of direct observation of the actual 
feeding habits of birds in open nature. It has the added advan- 
tage, which is great, that it does not involve the destruction of the 
life of the bird, which generally should be saved. It is constantly 
open to the objection that it can seldom be relied upon except 
when made by those trained by critical observational habits, for 
ordinarily the personal bias or equation of the observer is so dom- 
