RECOVERY FROM LEAD POISONING 
Recovery of sick mallards seemed to be influenced by one or both of two conditions: (1) natural 
passage of shot from the gizzard and (2) sufficient food intake to replace high weight losses. Most ducks 
that eliminated shot recovered, but their rate of recovery was slow if they were on an inferior diet. 
Most ducks that ate with renewed appetites, when a better diet was substituted, made rapid recovery 
whether they had eliminated or retained the shot. For example, 50 wild mallard drakes that were moder- 
ately or severely affected suffered an average weight loss of nearly three-quarters of a pound within an 
average of 22 days after being dosed. Twenty-eight days after being dosed they were placed on a better 
diet. In an average time of 26 days after the better diet was substituted, these same birds had regained 
all but an average of about one-tenth of one pound. 
A few severely affected individuals regained in the first week of their recovery period nearly all 
of the weight lost during 4 weeks of the experimental period. Examination by Dr. Paul D. Beamer, 
College of Veterinary Medicine, University of Illinois, of samples of the livers and kidneys from re- 
covered ducks failed to show the presence of any abnormalities caused by lead. 
Not all sick mallards recovered even when offered an optimum diet of duck pellets. Many were 
in such wretched condition that they either failed to eat or were “too far gone” to survive for more 
than a few days. 
RELATION OF STARVATION TO LEAD POISONING 
The behavior of lead-poisoned mallards, post-mortem examinations of those that died, and the 
phenomenal recoveries made by others led to the hypothesis that lead-induced starvation was the im- 
mediate cause of death. In order to test this hypothesis, mallards were paired, the age and sex of both 
birds of each pair being the same. One of each pair was fed a single no. 6 shot and the other was un- 
dosed. Food intake of the dosed bird was measured daily and exactly this amount was fed to its com- 
panion the following day. In nearly all pairs the weight loss curves, symptoms, and mortalities 
were remarkably similar. 
With minor exceptions, the gross appearance of the viscera, muscles, and blood of ducks from — 
which adequate food was withheld was indistinguishable from that in lead-poisoned ducks. The glandular © 
stomach, however, was never impacted, nor was food recovered from the digestive tract. The horny | 
lining of the gizzard, moreover, exhibited none of the effects commonly caused by direct action of lead. — 
The lining invariably was stained dark brown. 
19012! 
