Promote Avian-Friendly Power Lines
Millions of birds fatally collide with and are electrocuted by power lines annually. There are ways to prevent this!
The information on this page derives directly from the Avian Power Line Interaction Committee. Please visit their website at www.aplic.org for more detailed information. Check out the APLIC guidelines here.
Raptors are opportunistic and may use power poles for a number of purposes. In open habitats where few natural perches exist—such as deserts, grasslands, agricultural fields, and pastures—raptors are attracted to power poles, which provide roosting and nesting sites as well as hunting perches. However, utility structures can also pose a threat to raptors and other birds through electrocutions or collisions. Records of electrocutions and collisions date back to the late 19th century; however, avian deaths associated with power lines were not a widespread concern until the 1970s, when surveys in the western United States found hundreds of eagles shot, poisoned, and electrocuted in rural areas.
It is estimated that perhaps millions of birds including Bald and Golden eagles owls, and hawks die each year as a result of power line interactions Photo used with permission © Debi Shearwater.
Electrocutions occur when a bird completes a circuit by simultaneously touching two energized parts or an energized part and a grounded part of electrical equipment on a power pole, specifically with the span of its wings. The majority of electrocutions occur on medium-voltage distribution lines (4 to 34.5 kilovolts), the reason being that the spacing between conductors are oftentimes narrow enough to be bridged by a bird’s wingspan. Also, poles that contain closely-spaced energized parts (such as transformers) can be especially hazardous to birds off all sizes.
Power line collisions occur when birds fly into wires. Bird size, agility, experience, flocking, territorial or courtship activities, weather, time of day, human activities, configuration and location of the line, line placement, and line size can all contribute to these collisions.
When dead/injured protected birds are found as a result of power line/pole interaction, modification of these existing “problem poles/lines” is necessary. A “problem pole/line” is one where there has been a documented avian collision, electrocution, problem nest material or where there is a high risk of an avian mortality. When one is identified, engineers, operations personnel, company biologists, and consultants should meet to come up with a solution.
Two primary solutions can dramatically decrease the number of avian deaths that result from power line/pole interaction. The following information is provided and sanctioned by APLIC, the Avian Power Line Interaction Committee.
CONSTRUCT AVIAN-FRIENDLY POWER POLES TO BEGIN WITH:
When constructing new power poles, utility companies should ensure a safe distance between energized wires or between energized and grounded parts. The recommendations from APLIC is to provide a 60-inch minimum horizontal separation between energized conductors and/or energized conductors and grounded hardware, AND a vertical separation of at least 40 inches. These separations accommodate the typical height and wrist-to-wrist width of an eagle. In particular areas, such as areas with concentrations of wading birds, vertical separation may need to be increased to 60 inches. Because dry feathers act as insulation, contact must be made between fleshy parts, such as the wrists, feet, or other skin, for electrocution to occur.
RECONSTRUCT OR INSULATE PRE-EXISTING POWER POLES:
In the case of pre-existing power poles, reframing using a 10–foot crossarm may allow 60–inch separation between conductors. In other cases, pole replacement may be necessary. Additionally, hardware or conductors may be insulated against simultaneous contact if adequate spacing is not possible — covering material should be used to cover both the conductor and the insulator and if transformers, cutouts or other energized or grounded equipment are present on the structure, jumpers, cutouts and bushings should be covered to decrease the chance of a bird electrocution. Pole replacement utilizing a safe design may be required on poles where bird mortalities have been documented and other safe modifications are not feasible due to pole height or condition.
IMPLEMENT POWER LINE ADJUSTMENTS TO DECREASE COLLISIONS:
On existing lines, the risk of collision may be reduced or eliminated by burying or relocating the line, reconfiguring the line, removing the overhead ground wire, or marking the line to increase visibility. Because in most instances remediation of only a few spans will eliminate the problem, burying, relocating or reconfiguring the line are not cost-effective solutions. Removal of the overhead ground wire may not be feasible due to operational or safety concerns. However, research indicates that marking the shield wire (transmission lines) or conductors (distribution lines) to increase visibility significantly reduces the incidence of avian collisions. Marker balls, swinging markers, bird flight diverters, or other similar devices are commercially available products designed to increase the visibility of overhead wires.
Alliant Energy worker attaches triangular pieces of plastic designed to stop large birds from perching along a stretch of power lines where an eagle was electrocuted earlier. Published with permission © 2015 Iowa SourceMedia Group, Cedar Rapids, Iowa.
PERCHES ABOVE PERCH GUARDS: Over time, the solution described in this section has been found to be less effective than the above methods and is not primary recommendation.
Utility companies using perch guards are encouraged to implement insulation or reconstruction methods. We are including an explanation here to educate our readers on their existence and purpose.
If conductor separation couldn’t be achieved and covering or reframing is impractical, perch guards (triangles—like the one pictured to left) have been used to deter birds from landing or nesting on a certain pole to begin with. Perch guards are generally 18 to 22 inches wide and have been used when conductor spacing is less than 32 inches.
Discouraging birds from perching or nesting in unsafe locations solves only half of the issue, however. Ideally, when perch guards were installed, an alternative, safe perch site was also provided. Since raptors will often perch on the highest vantage point, the installation of perch guards between closely-spaced conductors and the placement of perches above existing arms and conductors have helped keep a bird from contacting energized parts or wires.
Contact utility companies!
Encourage utility companies across the country to implement similar avian-friendly alternatives to their power poles and lines. Urge them to create a voluntary Avian Protection Plan per the guidance of APLIC and the US Fish and Wildlife Service.
In addition to taking steps to reduce mortality risk to avian species, an APP also may include opportunities for a utility to enhance avian populations or habitat, including developing nest platforms, managing habitats to benefit migratory birds, or working cooperatively with agencies or organizations in such efforts. Where feasible, such proactive development of new ideas and methods to protect migratory birds should be encouraged and explored.