and beds of such plants are extensively shot over during the hunting season. Scaup ducks, in feeding 
largely on animal life in deeper waters, are perhaps less likely to come in contact with deposited shot. 
In general, the death rate in wild, unpenned ducks is higher among birds ingesting several pellets 
than among birds ingesting one pellet. Therefore, it is important to determine the frequency of the va- 
rious numbers of shot pellets taken. Among 18,115 gizzards examined, 5.28 per cent Eoneied ingested 
shot. Of those containing shot, 69.3 per cent contained only one pellet; 13.0 per cent contained two pellets 
and 17.7 per cent contained more than two pellets, fig. 12. This rate of ingestion applies to general 
conditions. The rate is, of course, higher among duck gizzards collected in severe outbreak areas. 
EFFECT OF INGESTED LEAD SHOT ON WILD DUCKS 
The effect of ingested lead shot on wild mallards is under evaluation through a field experiment. 
Banded mallards are being used as undosed control birds for purposes of comparison with other banded 
mallards dosed with lead shot. Bands returned have revealed differences between the dosed and un- 
dosed birds in mortality rate, hunter kill, and rate of migration. 
During the fall of 1949, two groups of trapped wild mallards were banded and released: (1) 560 
undosed and (2) 559 with one no. 6 shot pellet each. In 1950, three groups were released in the experi- 
ment: (1) an undosed control group of 389 ducks, (2) 391 ducks with one no. 6 pellet each, and (3) 392 
with two no. 6 pellets each. 
Band returns show that in the year of banding a significantly greater number of ducks were killed 
from groups dosed with lead than from undosed groups, fig. 18, indicating that ducks suffering from lead 
poisoning during the hunting season are more readily bagged than are the more healthy ones. Some of 
the lead-poisoned ducks shot by hunters are on the credit side of the mortality ledger; since the upper 
limit of the total take is governed by regulations, these birds become part of the planned harvest. This 
reduces the waste resulting directly from lead poisoning and is one reason so few ducks are found dead 
from lead poisoning during the hunting season. 
Band returns in the year of banding were sufficiently numerous from the 1950 release to deter- 
mine the difference in the rate of movement between healthy and lead-poisoned mallards, fig. 14. Ducks 
in the undosed group averaged about 7 miles per day between the place of banding and that of shooting. 
Ducks dosed with one pellet each averaged only about 5 miles per day, and those dosed with two pellets 
each averaged slightly more than 4 miles per day. Thus, it seems evident that migration of lead— 
poisoned ducks is retarded. 
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