Scientists: Mercury making birds gay

Too much mercury in the diets of white ibises can cause the birds to display same-sex mating practices, Florida scientists say. A study was performed on white ibis populations of the Panhandle State and Sri Lanka to determine why breeding was down.

"We knew mercury could depress their testosterone levels but we didn't expect this," Dr. Peter Frederick from the University of Florida, who led the study, told the U.K.'s Telegraph. "We're seeing very large reproductive effects at very low concentrations of mercury so we really need to be paying more attention to this."

High levels of mercury exposure caused lowered testosterone levels in the ibises, which in turn made it more likely that male birds would pair with other male birds.

The birds in the study were fed food pellets with mercury levels equivalent to those in the shrimp and crayfish in the birds' natural diets. Scientists believe the source of the mercury contamination could be run-off from mining and from burning coal and waste.