Claim markers are taking a gruesome toll on wild birds in Western US, says the American Bird Conservancy.
There are about 3.4 mining claims in the region that are mostly marked using PVC tubing, which the birds mistakenly believe are habitat.
"Small birds apparently see the opening of PVC pipes used to mark mining claims as a hollow suitable for roosting or nesting or possibly gathering to pool body heat during migration," writes the American Bird Conservancy in a news release.
"The birds may enter the holes, only to become trapped because the walls are too smooth to allow them to grapple their way up the sides and the pipes are too narrow for the birds to extend their wings and fly out. Death from dehydration or starvation follows."
An estimated one million birds are killed each year from the pipes. While a pipe pulling effort was underway in the Nevada Desert, ABC found an average of one bird death per pipe. The group found a single pipe with 32 bird deaths.
Most of the birds recovered at the bottom of PVC pipes are cavity nesters, like the ash-throated flycatcher and the mountain bluebird. Other victims include woodpeckers, sparrows, shrikes, kestrels and owls.
The American Bird Conservancy recommends PVC markers be capped or replaced with another material. The problem is difficult to control, since the impact is largely invisible and PVC tube is a low cost and convenient solution for marking claims.
The Bureau of Land Management is drafting policy to address the issue, although the department is looking for ways to coax miners into making changes rather than through mandates.
Image from Arizona Geology