October 1 opening in Minnesota and Wisconsin, as much as 75% of 
the opening-day kill is made up of blue-wings. When the season 
opened as late as October 7, the opening-day kill dropped to about 
25% blue-wings. These early season birds move out with the first 
cold snap, usually the first week in October; and in late October 
when the Illinois season opens, they are mostly gone, from the 
upper river and have thinned out even on Mark Twain Refuge to the 
south. 
4, A late opening day will also result in reduced wood duck 
kills since these birds, too, are killed in significant numbers 
only early in the season and are seldom checked in the bag after 
October 10. 
5. Since the presunrise success rate is higher than any 
other period of the day, the elimination of this period of hunt- 
ing will tend to reduce total kill. 
6. Since only 17.72% of the hunters in this area have taken 
three or more ducks on the day they were checked, it appears that 
liberalization of bag limits will affect only ahout a fifth of 
the hunters. This group, however, takes 56.48% of the total har- 
vest. Only 10.44% of the hunters take four or more ducks, 
accounting for 37.20% of the total kill. It was found that 36.97% 
of the hunters checked fell into the l- and 2-bird category, 
accounting for 43.52% of the total kill. Thus, it appears that 
an effective method of reducing total kill is by reducing bag 
limits which would not affect more than a fifth of the hunters 
in this area. It is postulated that dropping the limit from 4 
to 3 ducks would have saved 9.54% of the total kill recorded 
along the river in the past 15 years, while affecting only 10.444 
of the hunters. 
SUMMARY 
1. Bag-check data have been obtained on the Upper Missis- 
sippi River Wildlife and Fish Refuge since 1946 when they were 
initiated in conjunction with activities of the Technical Game 
Committee of the Upper Mississippi River Conservation Committee, 
on Calhoun Unit of Mark Twain Refuge since the same year, and 
from other units of Mark Twain Refuge as they came under manage- 
ment. 
2. Waterfowl utilization and bag-check information have 
been obtained over 284 miles of the Upper Mississippi Refuge 
involving 194,000 acres, and an additional 250 miles of Mark 
Twain Refuge between Rock Island, Ill., and Alton, Il1., involv- 
ing 67,695 acres. 
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