Table 38. Regional Differences in Age Ratios of Black Duck 



Area Age Ratio Sample Size 
Imm/ adult 
Minn., Wisc., & Mich. 2.70 285 
Ill. & Ia. 3 Ind. 3 & Ohio. 1. 92 105 
Rest of Flyway 1.60 65 

Table 39. Seasonal Changes in Age Ratios of Black Ducks 
SS 
Age Ratio 
State Period Imm/ adult Sample Size 
pa a SS 
Minnesota Octe 7-13 5.4 77 
Oct. 14=-Nov. 25 he 0 22 
Wisconsin Oct. 7-11 3.1 33 | 
Octe 12-Nov. 15 Ss 0 46 
Michigan Oct. 7-11 3.6 41 
Oct. 12-25 3.1 37 
Oct. 26 -Nov. 15 0. 8 31 
