The electrocution of raptors and large perching birds is a global hazard resulting from overhead distribution construction. This is especially true in treeless areas with abundant prey because poles make attractive perches. Disturbed by the continuing numbers of raptors — particularly eagles — electrocuted along power lines, the U.S. Fish and Wildlife Service is stepping up enforcement of the Migratory Bird Treaty Act and the Bald and Golden Eagle Protection Act. The utility industry has responded by working with vendors to produce several new products to address these issues.

In the past, products too often were produced without animal testing, which led to improper recommendations on how to protect animals from harm while maintaining reliable power. Recently, EDM International Inc. (EDM, Fort Collins, Colorado, U.S.) tested several animal-protection products in partnership with the Rocky Mountain Raptor Program (RMRP, Fort Collins).

The RMRP began in 1979 as an informal effort of veterinary students to care for injured birds of prey. It has since blossomed into an organization that combines university and community efforts dedicated to providing medical care, rehabilitation and release for injured birds of prey as well as environmental education for the public. The RMRP is part of Colorado State University, and 150 trained volunteers provide medical care for nearly 170 injured birds of prey annually. A partnership formed several years ago with EDM demonstrates how to safely frame distribution steel poles in a bird-friendly manner. Since then, a variety of products have been tested using captive birds and remote monitoring cameras.

Perch Guards

Perch guards are the most common mitigating devices, although little testing has been done on their effectiveness. Perch guards discourage birds from landing in hazardous pole areas and keep birds from defecating on suspension insulators and equipment. Perch guards come in a variety of shapes and materials; some allow installation under energized conditions while others require an outage to install. Triangular perch guards often are used to retrofit problematic lines in rural areas because they are economical and allow many installations in a day.

The goal of a perch guard is to discourage a bird from roosting in a certain area. This is most successful if safer portions of the pole are still available to the bird. It is important to note perch guards do not always keep birds off structures (Fig. 1) and are simply a tool to manage where birds can land on a structure. Perch guards can also simply shift problems onto other dangerous line segments and must be sized properly to discourage birds from perching under or next to the guards.

Like all utility components, guards should be installed according to manufacturer's specifications using National Electrical Safety Code (NESC) clearances to avoid potential electrical problems. Guards placed too close to conductors can lead to flash-over problems under certain environmental conditions. However, providing too much separation may allow birds to land next to guards.

The RMRP tested Coyote Enterprise's Raptor Guard Perching Deterrent RG36 to determine the space needed to keep birds off structures. This guard incorporates a patented X shape to provide maximum horizontal clearance between the insulator skirt and closest point of the deterrent.

For testing, the RMRP chose two raptor species: a golden eagle and a Swainson's hawk. It selected the eagle because it is the most commonly electrocuted bird in North America. The most commonly electrocuted hawk is the red-tailed hawk, which is similar in size to the Swainson's hawk used in the trials. The RMRP keeps these birds in captivity as educational birds.

Captive bird tests revealed that a Swainson's hawk requires 6 inches (15 cm) of separation before it will attempt to land between an insulator and the Raptor Guard Perching Deterrent (Fig. 3). Larger eagles require a minimum of 10 inches (25 cm) before attempting to perch between a guard and insulator. Accordingly, utilities should not increase their separation beyond these dimensions if the goal is to keep eagles and hawks off their structures.

In South Africa, specialized HDPE bird guards (Fig. 4) have been developed to eliminate bird streamer faults (see “Guarding Against Bird Outages,” Transmission & Distribution World, April 2001). The Mission Bird Guards are placed on transmission lines to mitigate vulture streamer and fecal-contamination problems. The RMRP tested the Mission Bird Guards to see if they also would be useful in reducing sage grouse predation. Distribution power lines located in sage grouse habitat provide additional places for raptors to prey upon these imperiled species. Federal and state agencies concerned about the decline of the sage grouse asked power companies to look into ways to deter power line perching in sage grouse habitat. Flight cage testing was conducted for seven days with five Swainson's hawks. The South Africa specialized Mission Bird Guards were successful at all perching attempts and did not harm the birds.

Elevated Perches

Perch management designs either encourage perching in safer areas or deter birds from perching in dangerous areas. Perch encouragement is done with elevated perches designed to attract birds to the highest point on the structure. When elevated perches are used, they should be designed so birds cannot get under the perch during the heat of the day or during inclement weather.

Elevated perches (Fig. 6) should be about 8 to 12 inches (20 to 30 cm) above a crossarm to prevent birds from sitting under the perch. They should be installed on structures located at topographical high points near a prey base. Perching deterrents can be used in tandem with elevated perches. As with all devices, install it properly so it does not create future operational problems.

A new product tested at the RMRP is the Aluma-Form Eagle Perch (Fig. 7). This new design was tested on poles donated and installed at the facility by Poudre Valley Rural Electric Association (Fort Collins). Testing was done to see if birds would use the new design, which includes both a horizontal and angle perching strut. Although the birds used the angled strut, they preferred the horizontal perch. Wind direction also can determine where raptors perch. Future designs rotate the upper Eagle Perch arm perpendicular to the lower arm so birds have the option of choosing a perch facing into the wind.

Moving Forward

Although utility-construction practices continue to improve, animal-caused outages persist. These outages often result in damaged equipment, safety problems and loss of service to consumers.

Nationwide, animals are the third-leading identifiable cause of all power outages, and birds cause more outages than any other animal. A recent EPRI study on animal-caused outages reports the development of outage-mitigating products is an emerging market with many products having increasing demand.

While many products comply with ANSI, IEEE and ASTM standards, there are few developed standards specific to animal protection devices. There also is a lack of testing with animals to determine product effectiveness. Manufactures should be encouraged to test products with animals to determine their effectiveness before marketing. This type of testing can be done inexpensively and often can lead to a better “mouse trap.”

Acknowledgments

The testing would not have been possible without the support and assistance of the Rocky Mountain Raptor Program (RMRP) and its dedicated volunteers. RMRP Director Judy Scherpelz has consistently supported efforts to develop bird-friendly utility products. Gail Kratz and Lisa Steffes also were invaluable handling the raptors throughout the captive trials.

Rick Harness is a wildlife biologist working for the engineering firm EDM International Inc. (Fort Collins, Colorado, U.S.). He has the MS degree in fishery and wildlife biology from Colorado State University, where he conducted his thesis work on raptor electrocutions. He has 21 years experience managing and supervising environmental studies and research for the electric-utility industry. Harness is presently working with utility manufacturers to develop new products to reduce avian electrocutions and collisions and recently helped produce a video on raptor electrocutions, Raptors at Risk.