|= x4 J; 
Na =z) ‘ 
oy Sy Le 
OAR ue 
1970 —( \he-f TGs) 
) non 30 40 SOMiles A] AK —1967 
Se 
) 
ENS 
Fig. 1.—Routes travelled in summer (1957-1970) to study breed- 
ing distribution of the birds of Illinois. The encircled areas were spe- 
cial study areas where daily censuses of migrants and nesting popula- 
tions of birds were carried out, 1967-1970. 
