The Food of Birds. 
Ill 
other according to their bulk and not their quality. A 
quart of caterpillars counts as the equivalent of a quart 
of blackberries, and, on the other hand, as the equivalent, 
also, of a quart of predaceous beetles. It is evident, 
therefore, that we cannot get at any close estimate of 
the economic values of this species in this indiscriminate 
way. 
A nearer approximation to the truth may be 'made by 
critically comparing the general averages for the year 
found in the vertical column at the right of the table. 
Here we have the following totals of injurious and bene- 
ficial species : Of the first, caterpillars, seventeen parts 
(including eight parts cutworms) ; Bibio larvae, fifteen 
parts; leaf-chafers, three parts; wireworms, two parts; 
snout-beetles, two parts ; crickets and grasshoppers, four 
parts. Of the second predaceous beetles, six parts ; pre- 
daceous bugs, three parts; garden fruits, twenty-four 
parts. Now, the opinions of entomologists would 
probably- be found to differ somewhat widely on 
the question of the relative values of these various 
elements, and each must form his own opinion from the 
data given.* My own judgment is that, taking into con- 
sideration only the immediate present effect of the robin 
upon the fruits and insects of the State, ignoring for the 
moment the important secondary disturbances likely to 
arise if the number of the species were greatly lessened, 
and balancing these elements carefully against each 
other (applying to them, in fact, the operation of cancel- 
lation in arithmetic), we. can reduce the question finally 
to about this form: Will the destruction of seventeen 
quarts of average caterpillars, including at least eight 
quarts of cutworms, pay for twenty-four quarts of cher- 
ries, blackberries, currants and grapes? 
To this question I, for my own part, can only reply that 
J do not believe that the horticulturalist can sell his small 
fruits anywhere in the ordinary markets of the world at 
so high a price as to the robin, provided that he uses 
* Concerning the value of predaceous beetles, the reader is especially- 
requested to examine the papers on that subject in the present bulletin. 
It is probable that their services have been greatly overestimated. 
