THE COWBIRD. 95 
especially the last, are the insects that might be supposed to attract 
the birds to the cattle, but the stomachs do not show that many are 
eaten, for altogether they amount to less than 8 percent of the food, 
and the wasps and ants are the most important constituents of this 
percentage. The wasps are probably picked from flowers while 
gathering honey and the ants are collected from the ground. The 
destruction of the latter is a decided benefit and the former can be 
spared. Hemiptera are represented in the stomach by stink-bugs 
(Pentatomide), leaf-hoppers (Jasside), and one cicada. While some 
of the pentatomids are useful insects, because of their habit of prey- 
ing upon others of a noxious character, many of them are serious 
is JAN.| FEB.| MAR) APR.) MAY [JUNE/JULY | AUG.|] SEPT] OCT.| NOV.| DEC. 
4 . 
100 
90) 90. 
80 80. 
f 
uN LEER REEEK OORS bee 
30 
40 
N 
s0\\\ \ 
NN 
= NIMAL=—F 00D 
20 
20 
10 10 
AN \\i 
Fic.3.—Diagram showing proportions of animal and vegetable food of cowbird in each month of the 
year. (The figures in the left margins indicate percentages.) 
pests; so on the whole it is probable that birds do little harm by eating 
them. The so-called leaf-hoppers live to a great extent upon grass 
and might very properly be called grasshoppers were it not that that 
name has been appropriated for other insects. Those eaten are so 
little that it would require a number of them to fill the stomach of 
evenasmall bird. All are harmful, and some, as for example those 
that feed on the grapevine and rose, are very injurious. Cowbirds 
eat a great many of these leaf-hoppers, which in some stomachs amount 
to 60 percent of the whole contents. The greater number are eaten 
in June and July, but the aggregate for the year is small, about 14 
percent. 
