However, this is an experiment with controlled in mallard ducks.
From the accumulation phase experiment found,
In nature if a female bird moved into, and began feeding in, a mercury-contaminated area during the reproductive season.
The level of mercury accumulated in eggs, and the possible harm from the mercury, would depend on how much mercury was in the diet of the female.
If, instead of moving into a mercury contaminated area as it began to lay eggs.
A female left a mercury-contaminated area and began feeding in an uncontaminated area, the concentration of mercury would be expected to rapidly decrease in successive eggs.
But , birds in the wild would lay fewer eggs than mallards laid.
Consequently, if a species laying a few eggs carried high body burdens of mercury, it probably could not eliminate enough mercury to decrease mercury levels in eggs to those believed to be safe.
The possible harm from mercury in eggs would depend on how much mercury was stored in her body and how long she was away from the contaminated area
Thus, less emissions of methylmercury into the environment as an alternative to allow concentration of mercury that accumulates in the bird decreased.