1925 ] Efficiency of Birds in Destroying Larvce of Corn Borer 39 
found the stations, feeding would result, whereas if the experi- 
ments remained undiscovered by birds able to take larvae from 
the cornstalks no evidence of feeding would be found. Whatever 
the reason, however, the fact of evidence of bird feeding on over- 
wintering larvae of this insect in cornstalks over a much more 
extended area during the spring of 1924 than was observed 
previously remains, and it is the writer’s belief that birds were 
a more important factor in reducing the numbers of the European 
corn borer in the spring of 1923 than in a corresponding period in 
1922, and that in the spring of 1924 they were of greater im- 
portance than in the same period in 1923; in other words, that 
the importance of birds as a means of natural control has been 
increasing each spring for the last three years. 
The figures showing the percentage of larvae taken by birds 
as shown in Table 3 represent the feeding up to the time that 
the experimental material was collected in the spring and so do 
not show the total amount of feeding that birds might have 
done had the material remained in the field a few weeks longer. 
As already mentioned, this same condition prevailed in the con- 
sideration of the experiments examined in the spring of 1923. 
It was necessary, however, to collect these experiments early in 
April because of a desire to examine the cornstalks before the 
larvae had moved from the exact locations in the stalks in which 
they rested at the time the material was set out the previous 
fall. 
It is probable also that birds were unable to remove some 
of the larvae from the staked experiments because in tying corn- 
stalks to the stakes that part of the stalks lying next to the 
stakes was rendered inaccessible to the birds. 
In the series of experiments examined in the spring of 1924, 
several of the experiments that showed no feeding by birds were 
located in areas that had been heavily infested by the insect for 
several years. Noticeable among those was the experiment 
located in Saugus, Mass, (table 3). This experiment was placed 
on a farm where corn had been severely infested each year since 
1919. In this instance, however, little corn was grown in 1923 
because of the heavy infestation previously experienced. A 
second instance of this condition was found in Marblehead, 
