SUMMARY 
1, This study of mallard, black duck, and blué-winged teal population losses in the 
Mississippi flyway is based on 10,718 of these ducks shot and recovered from 51,297 ducks 
banded at the Chautauqua National Wildlife Refuge or at McGinnis Slough in Illinois. 
2. Because the banding of mallards and black ducks was done during the hunting 
season and about half way down the flyway, a correction of year-of-banding return.data was 
made for these species so that the data would be comparable to the return figures in subse- 
quent years. As most of the blue-winged teals were banded before the hunting season opened, 
no correction of year-of-banding returns was made for these ducks, 
3. The mortality rate in a known age group, mallard drakes banded in the fall as 
juveniles, amounted to 55 out of 100 birds the first year, or year of banding, 20 the second 
year, 11 the third year, and 6 the fourth year. By the end of the sixth year, less than 3 of the 
original 100 were still alive. 
4, The only marked differences in mortality rates among year-classes of mallards 
was between juveniles and adults. Mallard mortality was about 1-1/2 times as great for juve- 
nile birds as for older ones; much of the difference resulted because juveniles are more vul- 
nerable to shooting, 
5. There was a higher mortality rate among mallard hens than among drakes. This 
higher rate apparently was not caused by hunting; it may have occurred because of natural 
disasters on the breeding grounds. 
6. Of three species of ducks, mallard, black duck, and blue-winged teal, banded at 
McGinnis Slough, the mallard had the lowest mortality rate; it was followed in order by the 
black duck and the blue-winged teal. 
7. The yearly hunter-bag rates followed a similar pattern for the three species. 
There was no consistent yearly trend in the hunter-bags, but the annual bag in the period 
1944-1947 averaged about 1.5 per cent more per year than it did in the period 1940-1943. 
8. Compared to other birds that have been studied for population mortality, mal- 
lards have a low rate of mortality. Although the blue-winged teal does not suffer the shoot- 
ing losses that mallards do, its mortality rate is higher. 
9. Band recovery data, corrected for proportion of bands unreported by hunters, 
and with estimated crippling losses included, indicate that hunters accounted for about 41 per 
cent of the 48 per cent annual mortality among Chautauqua-banded mallards, 1939-1947. 
10, The high shooting-loss component in the mallard's annual mortality loss is in- 
dicative that, during the 1939-1947 period as a whole, the shooting losses probably absorbed a 
large part of the losses that would have been ''natural'' in an unshot population. However, be- 
cause of the small part of the mortality loss left to be absorbed by natural losses, any marked 
increase in the shooting pressure over that occurring during the 1939-1947 period would un- 
doubtedly have raised the mortality rate. 
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