0 20 30 
APR 
10 20 30 9 
MAY JUN 
JUL AUG 
JUL AUG 
SEP 
a CENTRAL 
OCT 
20 30 9 19 29 10 20 30 10 20 
SEP OCT 
SOUTH 
20 30 9 19 29 10 20 30 10 20 
JUL AUG 
SEP OCT 
ig. 14.—Ege-laying and migration seasons of the wood thrush in different regions of the state (see Fig. 1). Spring and fall graph lines (1967-1970) 
ighest daily count of each 2 days. The lines are interrupted where data have not been collected. Star symbols represent counts made in other years or 
er observers. Shaded areas show the span of dates of egg laying. Dot symbols represent counts made on the western side of the state; lines without 
present the eastern side. 
Migration 
/e have seen wood thrushes still in molt as late as Sep- 
r 20 in central Illinois, and specimens killed at televi- 
lowers often show a few pin feathers in the body 
ge in late September. 
hen silent, wood thrushes are difficult to find, and 
ilence probably has much to do with the relative lack 
records (Fig. 14). We have recorded only 1 in the fall 
ery 15-20 in the spring. After the singing ends, in 
August, one occasionally hears the thrush’s distinctive 
totes, but generally the species goes undetected. 
latively few wood thrushes are killed at Illinois tele- 
towers. In a sample of several thousand specimens 
up in central Illinois, this species comprised only 
0.5 percent. They have been killed in migration at 
early as September 12 and as late as October 14. 
i’ censuses indicate that the migration is largely 
h by the end of September (Fig. 14). There are rec- 
r the wood thrush in northern Illinois in mid-No- 
"and late November (Fawks 1970, and Holcombe 
but these must be considered accidental. A winter 
or southern Illinois (Harlow 1921) is of doubtful 
r 
= 
Food Habits 
Forbes (1903) examined the stomach contents of 22 
wood thrushes taken from April to September, probably in 
central Illinois or central and northern Illinois. He found 
that among the thrushes and mimids, the wood thrush was 
near the top in the amount of insects taken (71 percent of 
the diet), and low in fruit consumption (19-21 percent). In 
the spring, the wood thrush was exceptional in the amount 
of millipeds it consumed (13 percent), and it also fed heavi- 
ly on ants (15 percent). Coleoptera (18 percent of the diet) 
were important, consisting mainly of ground beetles, scar- 
abs, click beetles, wireworms, and weevils. Forbes believed 
the wood thrush consumed fewer predaceous beetles than 
other thrushes. Flies, notably larvae of crane flies and Bi- 
bio, made up 12 percent of the food. Spiders and harvest- 
men made up about 1 percent of the diet, and molluscs 
about 1 percent. Rice’s data (1946) on food habits of the 
wood thrush are roughly comparable to Forbes’ data, 
though Rice indicated larger numbers of Hemiptera (10-20 
percent) in the diet than did Forbes (only 1 percent). 
In September we have seen wood thrushes feeding on 
the fruit of spicebush (Lindera benzoin), and pokeweed. 
lye 
