By Laura Zuckerman
SALMON, Idaho (Reuters) - Millions of birds have died and millions more are in danger from an obscure but widespread hazard in 12 Western states - uncapped plastic pipes used to mark many of the 3.4 million mining claims on public lands, wildlife advocates say.
Migratory birds from western meadowlarks and mountain bluebirds to screech owls and woodpeckers are mistaking the open ends of polyvinyl chloride, or PVC, pipes for natural hollows suitable for nesting, roosting or congregating to generate body heat.
Doomed birds enter the PVC pipes, which average 4 inches in diameter and stand about 4 feet high, but become trapped as they fail to gain traction on the smooth interior surfaces and cannot extend their wings to fly out of the narrow cavities. They eventually succumb to starvation or dehydration.
Federal land management officials acknowledge the threat, estimated by the American Bird Conservancy as responsible for at least 1 million bird deaths a year, although mining industry representatives say wildlife advocates exaggerate the problem.
PVC piping - durable, cheap and easily visible - became the material of choice for the flagging of mining claims in the West over the past several decades, wildlife managers said.
Those claims have proliferated under a century-old law that permits private citizens to stake rights to gold, silver and other "hard-rock minerals" on federal property administered by the U.S. Forest Service and the Bureau of Land Management.
Mining claim boundaries must be marked but the nation's hard-rock mining law - which dates to the 1870s and was enacted in part to promote development and settlement of the Western frontier - leaves it to states and mining districts to regulate how those delineations are made.
Government land managers insist they take bird mortality from PVC pipes very seriously and are assessing the full extent of bird die-offs across hundreds of millions of acres of BLM land and national forests.
"We're in clear acknowledgment of the issue and will be examining what guidelines or polices may be needed for structures that place birds at risk," said Chris Iverson, assistant director of wildlife for the Forest Service.
The BLM is looking at ways to coax, rather than mandate, changes in how mining claims are staked.
"We would expect to see a more immediate change with partnering rather than regulating," said Geoff Walsh, a BLM migratory bird liaison.
Possible steps include encouraging prospectors, through a letter or web-based campaign, to replace PVC pipes with solid markers such as wooden posts.
PUBLIC EDUCATION, VOLUNTEER EFFORTS
Government agencies, aware for years that uncapped PVC pipes were killing birds, have to date relied on public education to curtail the deaths, officials said.
But with populations declining among nearly two-thirds of all bird species found in the United States, the federal government is obliged by the Migratory Bird Treaty Act to prevent the incidental deaths of migratory birds and even to penalize violators, said Darin Schroeder, vice president with the American Bird Conservancy.
"This is a very significant bird mortality threat. Not only does the government have a legal responsibility, it has an ethical one," he said.
The conservancy's Robert Johns said the deaths came to his group's attention in recent weeks amid reports that volunteers in Nevada were removing the hollow markers beginning in November 2011 under a provision of a 2009 state law. Johns has since sought more information from wildlife agencies in the West.
"Every stone I turned over revealed more bad things," he said, conservatively estimating the potential number of uncapped pipes at 10 million.
Laura Skaer, executive director of the Northwest Mining Association, said bird groups are blowing the issue out of proportion.
"The estimates are just laughable to us," she said. "Unless they are really old claims that haven't been renewed, you're not going to find any PVC pipes."
Birders argue the Western landscape is littered with them. The trend is pronounced in Nevada, which is home to 1 million mining claims, many of them inactive, according to the BLM. A 1993 law in Nevada sought to reduce bird deaths by requiring capped pipes but the caps were routinely displaced or damaged by the elements, wildlife managers said.
John Hiatt, conservation chairman of the Red Rock Audubon Society in Las Vegas, said volunteer efforts to remove the PVC pipes hardly register in areas of a state where the white-colored markers appear "as far as the eye can see."
Nevada Department of Wildlife biologist Christy Klinger said the agency has freed up funds and gained donations from mining outfits to hire crews to remove pipes.
"But the problem is immense; how do you tackle that?" Klinger said. "Even if we had the manpower to do it, it will take years and years."
(Editing by Steve Gorman and Bill Trott)