105 
noteworthy advance in the subject both in methods of observa- 
tion and estimation of relative food values of.items concerned, as 
well as the relative importance of factors in the problem, which 
he termed “ Beneficial,” “ harmful,’ and “ neutral.” 
From that time up to the present work has been prosecuted 
by individual or organized activity, the latter chiefly under state 
or national supervision and support. 
Without in the least discrediting the work of individual 
investigation along this line, nor that of state entomologists and 
experiment stations, many of which have been important, it is not 
too much to say that the contributions from the United States 
Department of Agriculture have been noteworthy to a degree 
unequalled by any similar organization in the world, so far as I 
am aware. 
These reports, as separate documents, or as substantial com- 
ponents of the Annual Reports of the Department, have extended 
to almost every phase of bird life, so that data are available for 
estimating with reasonable approximation, the specific economic 
relation of a large proportion of our avifauna, and from a com- 
parison of habits affords grounds for approximate estimates of 
almost all. 
Aside from the general faunal relations of birds, concern- 
ing which it is not the purpose here to inquire, the economic 
aspect of birds presents an important problem which is two fold 
in its nature: 
t. That of the food consumed, and its direct commercial 
value, as for example, the rice of the bobolink, fruits and berries 
of robins, corn and other grains by crows, etc. 
2. That of the indirect problems involved in the relations 
of insects to vegetation, crops, etc., as modified by birds. 
While somewhat distinct problems they will be seen to 
stand closely related in a very large majority of cases and hence 
will of necessity have a generally coincident consideration. 
In the usual course of nature we might leave all such adjust- 
ments to the methods of nature; that is, in the struggle for exis- 
*Report U. S. Entomological Commission, Vol. I. 
