During spring migration, more than half a million Sandhill Cranes visit the shores of Nebraska’s Platte River, a critical stopover where the species has roosted for thousands of years. But for some unlucky birds, this ancient place of respite is a modern deathtrap. Every year, dozens to many hundreds of cranes suffer deadly collisions with two electrical transmission lines that cross the river at Audubon’s Rowe Sanctuary.
Now a biologist has landed on a new method that seems to slash crane fatalities at the property. If his results, published in a recent study in The Condor: Ornithological Applications, can be expanded to other sites, the technology would offer a new way for the industry to address a hazard that kills many millions of birds annually in the United States alone.
James Dwyer, a scientist who helps electric utilities build more avian-friendly infrastructure, embarked on the research because he saw that a key practice for trying to prevent accidents—the use of reflective, glow-in-the-dark, or other kinds of markers on the wires—wasn’t worth much when the sun went down. “It was clear to me that the industry standard was not having a sufficient effect,” he says.
With engineering colleagues at EDM International, the utility-technology company where he works, Dwyer developed what he dubbed an “avian-collision-avoidance system.” But while its name may sound better suited to a high-end jet, the system is actually rather simple; it's a solar-powered device fitted with ultraviolet lights that, when mounted on transmission poles, shine on the wires. The goal: Make the lines more visible to birds, while trying to avoid light pollution complaints from neighbors. “We went with UV light because birds can see it and people can’t,” Dwyer says.
Though he wasn’t certain that Sandhill Cranes could see the shorter light waves, more studies are showing a wide range of birds—from storks and puffins to loons and owls—have eye structures that detect violet or ultraviolet frequencies. Based on this, Dwyer launched forward with the experiment in spring of 2018. The results exceeded his expectations.
After the utility, Dawson Public Power, gave the go-ahead to test the system at Rowe Sanctuary, a technician monitored a single 850-foot span of power line on the property for 19 nights with the UV lights turned on and 19 with them switched off.
In the study, the team reported that the Sandhill Crane collision tally dropped from 48 in the nights without UV lights to only one with them. What’s more, the number of “dangerous flights”—instances when a flock approached near the line and didn't stop or swerve—also decreased by 82 percent, from 217 to 39. The researchers also noticed that more birds changed their flight path from at least 80 feet away from the line, giving them clearance room to avoid a brush with death.
At Rowe, the power lines are already fitted with colorful coils and hanging tags that have reduced some crane fatalities—so many collisions today occur either in foggy weather or at night. Sanctuary conservation director Andrew Pierson was impressed by the new results. “It seems quite positive," he says. "It seems like it worked."
Sanctuary staff are already in ongoing conversations with Dawson Public Power about options for reducing crane deaths, including bigger steps like burying the lines underground or redirecting them to a less sensitive location. If the new collision-avoidance technology becomes available, Pierson is optimistic the utility will consider it. He notes that it could also help Whooping Cranes, which face similar risks while passing through the Platte habitat.
“[The utility] is worried about collisions, too, especially collisions regarding an endangered, listed species. This represents a fairly cheap opportunity,” he says.
While the results are promising and offer a new preventative approach, more testing is required to demonstrate that UV lights work broadly for other birds and sites, says Richard Loughery, director of environmental activities at the Edison Electric Institute. He helps coordinate the Avian Power Line Interaction Committee, an industry collaboration with wildlife and conservation managers that funds research, works on siting issues, and publishes protocols for avoiding bird collisions and electrocution. The Aldo Leopold Foundation, for example, turned to these guidelines to win strong preventative measures—including lower towers and use of line markers—on a new transmission project near its Leopold-Pine Island Important Bird Area in Wisconsin, says the organization’s conservation director Steve Swenson.
Another open question is whether UV lights can be a substitute for line markers, or whether the two methods need to be paired up, like in Dwyer's study. Installation of line markers can require a helicopter, so it isn’t always cheap or easy, Dwyer says. Less expensive options, such as the UV lights, could lower the bar for utilities to monitor and protect more birds at a wider range of sites than they do today. That’s the upshot that Dwyer is striving for: "It can solve both the biology problem and the industry problem."