64 
COHORT 
1926-1930 
26 
92 ANNUAL MORTALITY 
COHORT 43 
I931-1935 
<~TU.S. BAG LIMIT 
LEGAL U.S.HUNTING & ~~ 42 
SEASON ee ‘ ps : 

12733 | 129433 ‘3135 13337 135139 
Figure 17,--Relation of Annual Mortality Rates to Hunting Pressure. 
Five-year moving averages of adult male mallard mortality 
rates for birds banded on the Pacific coast (table 57) 
are here compared with similar averages for the U.S. 
bag limit on waterfowl and the length (in days) of the 
legal U. S. hunting season in any given zone. 
