NATURAL ENEMIES: BIRDS. 
27 
control of these insects. No amount of "encouragement for the 
birds" or efforts to utilize their service in this direction can be 
expected to have any appreciable effect in reducing the number of 
leafhoppers, and we may dismiss this idea and turn our attention 
to other more hopeful agencies. 
It should be kept in mind distinctly that these conclusions refer 
only to the relation of birds to this particular class of insects and 
must not be used as an argument for or against the status of birds 
in relation to the control of insects in general or of any other group 
of pests. The writer is fully aware of the important service that is 
rendered by many of our common birds in the control of a number 
of serious insect pests and would by no means wish to contribute to 
any undervaluation of their service. 
The following list, with the leafhopper species arranged in alpha- 
betic order, shows the species of birds which have fed upon leaf- 
hoppers, the number of stomachs containing such material, with the 
total number of stomachs examined for each species and the per- 
centage for each record, as very kindly revised and corrected up to 
January 1, 1912, by the Biological Survey. 
Birds that have been found by stomach examination to have fed on leafhoppers; the latter 
. grouped by families. 
FULGOBXD2E. 
Name of bird. 
Name of insect. 
Total 
number 
of stom- 
achs ex- 
amined. 
Number 
of stom- 
achs con- 
taining 
insects 
of the 
family 
named. 
Percentages. 
137 
266 
1,159 
74 
0) 
971 
619 
2 
4 
1 
1 
1 
1 
1 
1, 1. 
do... 
2, trace, 1, 1. 
do 
9. 
....do... 
5. 
12 (12 spin.). 
2. 
Scolops maculosus 
10. 
CERCOPID^E. 
Accipiter cooperi 
Chamsea fasciata 
Geothlypis trichas 
Iridoprocne bicolor 
Melospiza melodia 
Otocoris alpestris 
Quiscalus quiscula 
Sturnella magna 
Penthestes atricapillus. 
Polioptila ca?rulea 
Setophaga ruticilla 
Sitta pygmaea 
Cercopidre 
do 
do 
do 
Cercopida? (1 with 5 spm.). 
Cercopidae 
do 
Thryomanes bewicki. . . 
Chordeiles virginianus . 
Chordeiles virginianus. 
Junco aikeni 
.do. 
.do. 
.do. 
.do. 
.do. 
do 
Aphrophora sp 
Clastoptera xanthoccphala 
(12 specimens.) 
Ptyelus sp 
100 
1 
170 
1 
130 
1 
164 
1 
718 
3 
0) 
2 
2,384 
1 
1,157 
2 
644 
3 
39 
2 
17 
2 
32 
18 
153 
1 
(') 
1 
(') 
2 
1 
1 
Trace. 
12. 
30. fc 
10. 
15, 5, 100. 
12, 20. 
2. 
5,2. 
50, 79, 90. 
30, 20. 
81, 50. 
100, 88, 100, 20, 79, 
83, 90, 100, 77, 25, 
50,72,45,100,100, 
100, 85, 65. 
6. 
Trace. 
Trace, 1. 
40. 
1 Number of stomachs recorded elsewhere in this list. 
