LAS VEGAS (AP) — A Nevada wildlife researcher has found that not even the fastest bird on Earth can escape mercury contamination.

The toxic element is turning up in feathers of peregrine falcons from coast to coast, including those at the Lake Mead National Recreation Area, state Department of Wildlife biologist Joe Barnes told the Las Vegas Review-Journal.

Over the past decade, Barnes has tested for mercury in 700 individual peregrines in southern Nevada, Washington, Maryland and the Gulf Coast of Texas.

"Every single one of them was impacted, regardless of whether they live in wide-open desert or Lake Mead or Greenland or coastal British Columbia," he said.

Barnes' latest findings were published in February in the Journal of Raptor Research.

More research is needed to determine how much mercury peregrine falcons can tolerate, Barnes said. But studies of other raptors suggest concentrations of between 5 and 15 parts per million can significantly reduce breeding.

Barnes documented average mercury levels of 17 ppm in adult peregrines at Lake Mead near Las Vegas, and 23 ppm in adult peregrines along the Washington coast. Even falcons migrating south from remote Greenland, Alaska and northern Canada, far from industrial pollution sources, carried about 10 ppm of mercury in their feathers on average, he said.

Peregrines are "one of the most impacted species when it comes to contamination," Barnes said, because they feed on other birds that have been exposed to mercury.

At Lake Mead, favorite peregrine prey is the eared grebe, a small water bird that migrates through the area by the hundreds of thousands.

Barnes said most grebes at Lake Mead also spend time in mercury-laden waters of Utah's Great Salt Lake.

The peregrine falcon hunts almost anything that flies, including birds and bats. It dives on prey from above with wings closed, enabling it to reach speeds of more than 200 mph.

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