By: Brayden Yin

It’s a fact of life that birds are often electrocuted while resting on power lines. Many birds found dead, especially ravens and raptors, are assumed to have died from electrocution, especially if their corpses show burns or singeing. But people shooting the birds off the lines is an even bigger problem, as shown from a study of 4 Western states published on Tuesday.

Eve Thomason of Boise State University in Idaho noted that while many birds succumb to electrocution, the animal could have been injured or killed even before they were shocked.

“We really need X-rays to understand fully what may have happened,” she said. Thomason used to work for a utility that surveyed power lines to determine how safe they were to birds.

Thomason and her colleagues surveyed 122 miles of power lines, spanning Idaho, Oregon, Utah, and Wyoming, and collected 410 bird carcasses. In the lab, the researchers X-rayed the bodies, and most of the carcasses contained bullet fragments or shotgun pellets. For the 175 birds in which a cause of death was successfully determined, 66 percent were shot.

There have been reports of such shootings, but nobody has done a large-scale report at these multiple sites to find out if shooting birds is a significant problem. Moreover, the proportion of birds shot varies widely at the different sites. At two sites, all of the deaths were confirmed to be attributed to gunshots. At another, shootings only accounted for 39 percent of deaths, with a similar amount for electrocution.

The birds shot or electrocuted were mostly ravens or raptors, which includes eagles, hawks, and falcons. Under multiple U.S. laws, shooting these birds is illegal. Research is still being carried out to determine why people shoot so many birds off power lines in the U.S.