
x Le) 
@ 50- ” 
E 30 MORTALITY INDEX IS 
< 20 lio> 
x 10 3 . 5, © 
a “RECOVERY RATE |? w 
1940 1941 1942 1943 1944 1945 
—~4| —42 ~43 -44 -45 —46 
Figure 15.--Adult Mortality Index for Missigsippi Valley 
Mallards Compared to Adult Recovery Rates 
for Birds Banded in Canada and Northeastern 
Illinois 
131 
