Photo: foxypar4 (flickr)

The color of Great Lakes herring gull eggs indicate how contaminated they are,  according to a study in the Journal of Applied Ecology.

And that may provide clues about the level of contamination in the surrounding environment.

Researchers examined subtle differences in egg color. They found that the more contaminated eggs were less blue-green in color.

Contaminants are eaten by birds and passed to their eggs.  The mother also passes on the blue-green and brown pigments found naturally in her body to her eggs, Daniel Hanley, a postdoctoral fellow at the University of Guelph and an author on the study, told the Toronto Star.

The researchers  suggest that the egg color could be applied in future studies as indicators of the level of contamination in the environment.

Checking egg color is fast, cheap and a nondestructive way to estimate pollution, the study said.

A separate study reported in March that chemical pollutants from Great Lakes manufacturers are in herring gulls.