

different age ratios (Figure 5). A sample of 216 wings from the 
northeastern zone averaged 2.93 immatures per adult. The age ratio 
was 1.44 immatures per adult in a sample of 414 wings from the middle 
zone (from the northwest corner through the middle portion of the 
State at the eastern boundary). In the remainder of the State (most 
of the southern half), the age ratio in a sample of 468 wings was 
only 0.73 immature per adult. Thus, age ratios increased from west 
to east and south to north within the State of Minnesota just as 
they did from State to State. The birds harvested in extreme north- 
eastern Minnesota probably came from an area of relatively success- 
ful production, whereas those taken in the southern portion of the 
State probably came from an area where production had been much poorer. 
Age-ratio data from Missouri and Illinois did not show any 
significant regional differences within the States. Age ratios along 
the Mississippi River in Missouri, however, were somewhat higher than 
those in the interior. The age ratio in samples from the counties 
adjacent to the Mississippi River in Missouri was 0.59 immature per 
adult, whereas the age ratio in the remaining counties was 0.47 
immature per adult. 
A sample of 830 wings from the extreme northeastern corner of 
Arkansas had an age ratio of 0.53 immature per adult. The age ratio 
in a sample of 52 ducks taken in east-central Arkansas in the vicinity 
of Stuttgart was considerally lower, only 0.27 immature per adult. 
This difference suggests that the sample for the State as a whole was 
not properly representative, and that the age ratio for the State 
should have been lower. 
4. Mallard age ratios from bag checks and supplemental 
wing collections 
In addition to age-ratio data from the wing collections, infor- 
mation on age ratios was obtained by examining ducks stored at locker 
plants, inspecting hunters' bags, and making supplemental collections. 
The purpose of the additional effort was to obtain age-ratio infor- 
mation from a wider geographic area than was covered by the mail- 
wing collection, and to see how well data from bag checks and supple- 
mental wing collections agreed with the data from the mail-wing 
collectione 
Arthur Hawkins summarized the results of bag-check information 
in the Mississippi Flyway, and distributed the information to Mississippi 
Flyway Council members in the form of memos during the 1959-60 hunting 
season. Table 36 summarizes his age-ratio observations as presented 
in these memos. In Minnesota, age ratios were determined by examining 
ducks in locker plants in the Twin Cities and in hunters’ bags at the 
Roseau River Refuge. Birds in the locker plants were shot over a 
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