Newswise — Birds can get electrocuted on power lines when they touch two energized parts together while taking off or landing. Energy companies spend time and money to make power lines safer for birds by adding safe perches and insulation. However, a recent study in iScience shows that illegal shooting is now a major cause of bird deaths on power lines, surpassing electrocution as the leading threat.

The first author, Eve Thomason, a research associate at Boise State University's Raptor Research Center, emphasizes that solving conservation problems requires accurately identifying their causes. In the case of bird deaths along power lines, understanding the specific reasons is crucial to developing effective strategies for reducing such fatalities.

Thomason, who previously performed avian risk assessment for a power company, noticed dead birds on power lines that should have been safe from electrocution. Realizing many were shot, she led a four-year investigation covering 196 kilometers of power lines in four states. They collected 410 carcasses, mostly of protected species like eagles, hawks, and ravens, and analyzed them in the laboratory to determine the cause of death.

Thomason highlights the uniqueness of their study, stating that they meticulously documented, collected, and X-rayed all bird remains. Unlike previous studies that focused on birds in better condition and occasionally performed X-rays, they made an effort to identify the cause of death for every bird they discovered.

Through X-raying all bird remains, the researchers gained the ability to accurately detect bird shootings, even when the cause of death was not evident externally from the carcass. For instance, they examined a bald eagle that was initially believed to have died from electrocution by the power line owner. However, upon X-raying the bird, they discovered multiple shotgun pellets and entrance wounds scattered throughout the eagle's body, indicating that the bird was shot and then came into contact with the power lines as it fell to the ground.

The team intends to continue their surveys along power lines and explore new regions to assess the extent of illegal shooting. They aim to understand the reasons behind the bird shootings. This valuable information will assist law enforcement in planning patrols and investigations to prevent further illegal shooting incidents.

Thomason acknowledges that they are still in the early stages of understanding this problem, and it can be challenging to determine the motives behind the illegal shooting. However, based on their research, they have discovered that some people shoot protected birds for enjoyment, while others do it to safeguard their livestock from predators. Due to the complexity of the issue, the team values their strong connections with government agencies and utility companies. In the future, involving all these stakeholders will be crucial to developing effective solutions.

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Journal Link: iScience