104 
The Food of Birds . 
one per cent, each of Arachnida and Myriapoda are the 
remaining trivial details. 
August. 
This month is represented by twenty birds, all shot at 
Normal,* at repeated intervals from the fourth to the 
thirtieth. With the disappearance of blackberries, the 
food of this bird returns substantially to the status of 
June. Insects increase again to forty-three per cent, and 
fruits fall to fifty-six. Ants remain at the usual point of 
insignificance, caterpillars rise again to seventeen per 
cent., about two-thirds of them Noctuidae. Coleoptera 
figure at seven per cent., only two per cent, being Carab- 
idae, Bhynchopliora rise to four per cent., eaten by nine 
of the birds; and, except a stray Nepa picked up by one 
robin, Hemiptera appear in trifling quantity. Crickets 
and grasshoppers are more abundant, amounting to ten 
per cent, of the food. 
The cherries made forty-four parts of the food of the 
month, eaten by fourteen of the birds, but two-thirds of 
these cherries ivere tvild. Tame grapes make three per 
cent, of the food, berries of the mountain-ash about four 
per cent., and blackberries from the woods not far from 
five per cent. 
September. 
Twelve birds, all but one shot at Normal September 
25th, and that one at Aurora on the 13th, show no more 
remarkable peculiarity than the substitution of ants for 
most of the caterpillars, the former composing now fif- 
teen per cent, of the food, and the latter but five. The 
ants were largely winged, but of different species from 
those taken most freely in June.f The Carabidae of this 
month were chiefly larvae. Among the Hemiptera (throe 
per cent.) were found Mormidea lugens and Camus 
* The general cessation of taxidermist’s field work in midsummer has 
prevented the supply of any material for this month and the preceding, 
except that obtained by ourselves in McLean county. 
t Examining the tables of food of the bluebird, brown thrush and robin, 
I 1 find throughout a curious inverse relation between the ratio* of ants 
and caterpillars, the latter falling away in June to about the sa mo degree 
that ants increase during the time of their most conspicuous activity. 
I cannot even guess why ants should thus replace caterpillars in the 
food. 
