NORTH 9 
al | \ | EGG LAYING 
e Span of dates 
I 4 
100 
BIRDS COUNTED PER DAY 
MAR APR MAY JUN JUL 
, Fig. 18.—Egg-laying and migration seasons of the barn swallow in different areas of the state (see Fig. 1). Spring and fall 
lines (1967-1970) show the highest daily count of each 2 days (left scale). Asterisk symbols represent counts made in other 
or by other observers. Shaded areas show the percent of eggs laid on a given date (right scale) or the span of dates during 
egg es. has been recorded. Dot symbols represent counts made on the western side of the state; lines without dots represel 
eastern side. 
20 
