1925 ] Efficiency of Birds in Destroying Larvce of Corn Booer 35 
infested areas and in localities that had been infested for several 
years. In sparsely infested localities or in areas where infesta- 
tion had been severe only recently, no extensive feeding was 
noticed although in some cases there were traces of feeding by 
birds. The following table shows the condition as found in 
certain heavily infested fields that were found to be attacked by 
birds. 
TABLE II. 
Extent of Feeding by Birds on Material Undisturbed by Man in the 
Spring of 1923 . 
Locality 
Date 
examined 
Type 
of | 
corn 
Condition 
of corn- 
stalks 
Size 
of area 
Estimated 
number 
of larvae 
taken by 
birds 
Estimated 
per cent 
of larvae 
taken by 
birds 
Watertown, Mass. 
IV-2-23 
Sweet 
Standing 
1 
and broken 
over 
1 \ acres 
186,480 
92 % 
Watertown, Mass. 
IV-6-23 
U 
standing and 
broken over 
I acre 
26,957 
78 % 
Milton, Mass. 
IV-13-23 
“ 
Lying on 
soil 
1 acre 
30 % 
Marblehead, 
V-3-23 
u 
standing and 
Mass. 
broken over 
A acre 
140,946 
97 % 
Melrose, Mass. 
V- 1 1-23 
“ 
In piles 
partly burn- 
ed 
80% 
The figures mentioned in this table were obtained by 
counting the number of cornstalks in the several fields, estimat- 
ing the fall infestation of the stalks, and comparing this figure 
with the average infestation found on the date of the examina- 
tion. The spring infestation per cornstalk was obtained by 
averaging several series of counts made in different parts of each 
field. In all these instances both types of bird feeding shown in 
figure 1 were found, the feeding attributed to woodpeckers 
being extensive in standing stalks and the stalks lying on the 
ground being shredded by other birds. 
In weeds instances were found of the removal of considerable 
numbers of larvae from cocklebur ( Xanthium sp.) and barnyard 
grass ( Echinochloa crusgalli L.). In one field several score of 
