Water pollution is posing a threat to bird population by causing males to go gay, scientists say. Researchers believe poisonous metal compounds entering the food chain can affect bird sexuality, causing a reduction in offsprings. This is the first scientific study to show how pollutants alter sexual preferences.
Scientists found that even relatively low levels of methylmercury in the diet of male white ibises caused the birds to pair up with each other, snubbing females, reports the Daily Mail. Methylmercury is a form of mercury – the metal which is liquid at room temperature and is better known as quicksilver. It has been seeping into groundwater from industry for years.
Peter Frederick from the Florida University in the US captured 160 young white ibises, a coastal wading bird, and gave them food laced with methylmercury. The birds were split into four groups. One group ate food with 0.3 parts per million (ppm) methylmercury, which most US states would regard as too high for human consumption.
A second group was fed 0.1 ppm, and the third 0.05 ppm, a low dose that wild birds would be exposed to frequently. The fourth group was not given the substance. All three groups which were given methylmercury had significantly more homosexual males than the control group. Male-male pairs courted, built nests together and paired off for several weeks.
Higher doses increased the effect, with 55 percent of males in the 0.3 ppm group being affected. “We knew mercury could depress their testosterone levels,” explained Frederick. “But we didn’t expect this. In the worst-case scenario, the production of young would fall by 50 percent. Other birds would probably be similarly affected,” he said.