While Bird on a Wire, a 1990 film, was a romantic comedy, there is little amusement about the very real problem of birds on wires—or, more accurately, birds flying into wires.

Birds, particularly such august denizens of the sky as eagles, hawks, and ospreys, have been flying into power lines for far too long. Once the problem was fully realized, the Electric Power Research Institute and the Edison Electric Institute started trying to halt the needless self-destruction of birds of prey.

As demand for power has increased—and nowhere more so than in EPRI's home state of California—so have the miles of power lines.

With the burgeoning of power lines has come an inevitable concern for bird collisions and electrocutions. It goes beyond sympathy for the birds, since their encounters with power lines cause power outages that can cost utilities hundreds of thousands of dollars.

In an attempt to counteract the problem, EPRI began an avian interaction program more than a decade ago. Pacific Gas & Electric had developed an automated system to gather scientific data on bird collisions.

"PG&E transferred the technology to us," recalled Rick Carlton, a biologist who directs EPRI's program. "The biggest problem with birds flying into power poles is the lack of quantification of the problem."

EPRI biologist Rick Carlton said that "we need to learn more about bird behavior" to deal with the problem of collisions and electrocutions on power lines.

EPRI, a Palo Alto-based manager of science and technology programs for the energy industry, has three major goals for the bird-on-a-wire problem: to benefit birdlife, to reduce the impact of birds on the power industry, and to aid utilities in complying with the legal requirements enforced by the U.S. Fish and Wildlife Service.

EPRI has co-sponsored several workshops in recent years, bringing together utility engineers, biologists, and wildlife personnel to discuss ways of solving common problems. "There's no shortage of great ideas," said Carlton. "But many of the methods have not been thoroughly tested."

To that end, Carlton, working with the California Energy Commission, the U.S. Fish and Wildlife Service, utilities, and others, has been setting up a bird activity monitoring system to study some promising methods for reducing collisions and electrocutions.

The system consists of day and night video cameras together with radar and acoustic monitors. A video camera can be aimed at a problem area or, alternatively, at a pole fitted with protective devices. As birds approach, the video camera begins recording. The resulting information can help utilities identify the exact nature of the problem or test mitigation methods before retrofitting many miles of power lines with insulators and perch guards.

Besides the bird activity monitor, EPRI is testing a bird strike indicator, with no need for people to tend it. The system uses an accelerometer (about the size of a lunchbox) that clamps on a power line with a hot stick. The hot stick enables a lineman to work on a line while it is in service. Utility technicians clamp a sensor device on a line and if a bird collides, it sends a signal to a ground base unit that stores the data. The sensor has to distinguish among birds, hail, and other substances hitting the line. EPRI hopes to complete testing by the fall, according to Carlton.

The institute plans to mount a site in North Dakota near an Audubon wildlife preserve that is losing about 100 birds a year. Only birds that hit and land on a nearby road are retrieved. Those falling into water on either side of the road are lost and uncounted.

Carlton admitted that a snapshot will hardly show the full extent of the problem. "Wind and weather can affect flight patterns. Wet weather can make a bird's feathers more conductive, increasing the potential for electrocutions," he said.

"What makes certain areas hot spots is the location of power lines in relation to migratory routes," said Carlton. Birds of prey seek the highest perch available from which to hunt, and if there are no tall trees around, they go for power poles. "They go to whatever is highest. To get them off power poles, simply put up something that is higher," he said.

Birds migrating at night, such as warblers, thrushes, and vireos, are susceptible to collisions with lit towers over 200 feet. This is especially true in fog, mist, or low cloud cover, when the flashing lights on towers attract birds.

A utility can solve about 80 percent of its problem by fixing 10 percent of its poles—the ones most attractive to raptors. "Ninety percent of the problem usually occurs in about 10 percent of the poles," said Carlton. Experts estimate that it costs about $150 to retrofit a pole and make it safe for birds.

Peter Easton

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