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. . Raptor Res. 33(1) 39-42 J. : © 1999 The Raptor Research Foundation, Inc. CREATING RAPTOR BENEFITS FROM POWERLINE PROBLEMS Michael N. Kochert^ and Richard R. Olendorff^ U.S. Bureau ofLand Management, Raptor Research and Technical Center, 3948 Development Avenue, Boise, ID 83705 U.S.A. Powerlines benefit raptors by providing en- At least 17 species of raptors have been electro- hanced nesting and roosting sites. However, they cuted in the U.S. (Williams and Colson 1989). also can kill raptors by electrocution and raptors Large raptors are more susceptible to electrocu- can interfere with power transmission. The electro- tion because they more easily span the distance be- cution problem has been reduced by correcting ex- tween energized wires (Olendorff et al. 1981). isting lethal lines and implementing electrocution- Golden Eagles {Aquila chrysaetos) bave been the safe designs for new lines. Remedial actions most commonly electrocuted raptor, and most are include pole modifications, perch management subadults (Boeker and Nickerson 1975, Olendorff and insulation ofwires and hardware. New line de- et al. 1981, Benson 1982, APLIC 1996, BLM, un- signs provide for proper insulation and adequate publ. data). The susceptibility of young eagles to spacing of conductors and grounded hardware. electrocution may be due to their inexperience in Nesting platforms can reduce power transmission flight (Nelson and Nelson 1977, Olendorff et al. problems and enhance the benefits of nesting on 1981). Most Golden Eagle electrocutions appar- A powerlines. combination ofperch deterrents and ently occur in winter (Benson 1982, PacifiCorp, insulator shields is a positive, cost-effective ap- unpubl. data). Inclement weather (rain, snow and proach to managing bird contamination that al- wind) during winter increases the susceptibility of lows birds to continue roosting on the towers. raptors to electrocution because of reduced flight maneuverability and increased conductivity of wet Problems Affecting Raptors feathers (Olendorff et al. 1981). Powerlines benefit raptors by providing en- The electrocution problem is more acute in hanced perch sites for hunting (Olendorff et al. grass and shrublands of the western U.S. and in 1981). However, they can also adversely affect rap- areas where natural perches are scarce (Boeker tors (Olendorff et al. 1981, Williams and Colson and Nickerson 1975, Benson 1982, APLIC 1996). 1989). In the U.S., raptor collisions with or entan- In the U.S., electrocutions are more prevalent on glements in powerlines or tower lattices are not distribution lines (^69 kV) than on high voltage m^or problems (Olendorff et al. 1981, Olendorff transmission lines (Boeker and Nickerson 1975, and Lehman 1986) and shooting ofraptors on util- APLIC 1996). Raptors are rarely electrocuted on ity poles appears to be less of a problem than elec- transmission lines or low voltage lines (<1 kV, AP- trocution (Peacock 1980, Benson 1982, APLIC LIC 1996) 1996). Powerpole configuration influences the proba- A raptor electrocution problem became appar- bility of raptor electrocution more than voltage ent in the U.S. in 1971 (Olendorff et al. 1981). alone (Williams and Colson 1989). Lethal config- Concern stimulated testing of powerline designs urations usually do not have adequate spacing be- that were safe for raptors (Nelson and Nelson tween the phase conductors and ground wires or 1977). This work culminated in the three editions grounded hardware to prevent large raptors from of “Suggested Practices for Raptor Protection on touching them (Olendorff et al. 1981). Poles with Power Lines” (Miller et al. 1975, Olendorff et al. additional hardware (i.e., transformers, switches, 1981, APLIC 1996) which provide guidelines for jumpers, other extra wires) are also lethal (Olen- managing the electrocution problems. dorff et al. 1981) Certain powerpoles are preferred by eagles and 1 Present address: USGS Forest and Rangeland Ecosystem have a greater probability of electrocuting birds Science Center, Snake River Field Station, 970 Lusk St., (Nelson and Nelson 1977, Olendorff et al. 1981, Boise, ID 83706 U.S.A. Benson 1981, 1982). “Preferred” poles are either ^ Deceased. more elevated above the surrounding terrain or in 39 . 40 Expanded Abstracts VoL. 33, No. 1 areas with higher prey densities (Benson 1981). Insulation is often used in conjunction with elevat- Pole arms that are diagonal or parallel to the pre- ed perches and is an economical option when only vailing winds tend to have a higher incidence of a few poles need modification (APLIC 1996). electrocutions (Nelson and Nelson 1977, Benson The armless design is effective in minimizing 1981, 1982). raptor electrocutions provided there is adequate Alleviation ofthe electrocution problem involves spacing (152 cm) between wires and hardware correcting existing lethal lines (pole modifications, (APLIC 1996). This design is more expensive than perch management and insulation) and imple- the conventional crossarm designs, and it creates menting new line designs that are safe for raptors. extra hazards to line crews (Olendorff et al. 1981) Objectives of these improvements are to provide Certain 69-kV armless configurations once be- adequate separation between energized wires and lieved to be raptor-safe were recently found to be hardware and adequate insulation of wires and lethal to eagles due to grounding problems (AP- hardware where sufficient separation cannot be ob- LIC 1996). The problem was resolved by placing tained. Modifying every pole along a line is cost- perch guards on the top of the insulators or re- prohibitive and perhaps unwarranted from a bio- placing insulator posts with longer ones (Pacifi- logical prospective (Williams and Colson 1989, Corp, pers. comm.). Single-phase configurations APLIC 1996). Action should focus on identifying should leave the top 50-75 cm of the pole free of and correcting chronically lethal poles (i.e., “pre- wires or other hardware (APLIC 1996). Three- ferred poles”) and monitoring the success of the phase designs should provide adequate conductor remedial action. Nelson and Nelson (1977) felt spacing (152 cm) by using a taller pole and lower that most electrocutions could be prevented by placement of the crossarm (APLIC 1996). correcting only about 2% of the poles. Underground construction is an obvious solu- The three-phase single-pole construction with a tion to the raptor electrocution problem. Although crossarm has been associated with most electrocu- this practice is used in Europe and in urban areas tions (Olendorff et al. 1981, APLIC 1996). Meth- of the U.S., it is considered too expensive for wide- ods to modify problem poles involve increasing spread application in rural areas of the U.S. (AP- conductor spacing and include (1) raising the cen- LIC 1996). Underground lines also occasionally ter phase, (2) lowering the crossarm, (3) suspend- present design problems, particularly for high volt- ing the outer phases below the crossarm and (4) age transmission lines (APLIC 1996). placing longer crossarms on the pole. The objec- Nelson (1982) felt that the raptor electrocution tive of these methods is to provide at least 152 cm problem in the U.S. had been reduced in the 1970s separation between conductors (Olendorff et al. through cooperative efforts of government agen- 1981, APLIC 1996). cies, conservation organizations and the electric in- The next most lethal configuration is a single- dustry. It is debatable, however, whether electro- phase line with the conductor on top of the pole cutions have decreased in recent years (APLIC and a ground wire near the top insulator (Olen- 1996). However, awareness of the issue and efforts dorff et al. 1981). The problem was solved by low- to resolve it have increased, and raptor electrocu- ering the pole ground wire at least 30 cm below tions have decreased in areas where powerlines the top of the pole or cutting 10 cm gaps in the have been modified. Electrocution still occurs in ground wires (Olendorff et al. 1981, APLIC 1996). the U.S., and it is a major problem in certain areas Elevated perches place birds above any danger (APLIC 1996). Resolving electrocution problems is and perch guards discourage raptors from perch- a continuing cooperative effort between the utili- ing on dangerous parts of powerpoles (Olendorff ties and the regulatory agencies involving an “in- et al. 1981, APLIC 1996). They are used when ad- tegrated management approach” (APLIC 1996). equate separation ofwires and hardware cannot be In this approach agencies and utility companies obtained or when pole modification is infeasible. formally agree to action guidelines and standard Perch guards are often used in conjunction with operating procedures to identify and rectify prob- elevated perches. lems. Wires and other hardware are insulated on poles Power Transmission Problems with wires connecting transformers and other pieces of equipment or when modifying poles is Powerlines benefit raptors and other large birds impractical (Olendorff et al. 1981, APLIC 1996). by providing enhanced nesting and roosting sites March 1999 Expanded Abstracts 41 (Engel et al. 1992, Steenhof et al. 1993). The ben- tract raptors to specific towers or positions on tow- efits to nesting raptors are compromised by prob- ers and to enhance raptor productivity, and that lems associated with power outages from nesting nest removal was ineffective and unnecessary. material, feces or electrocuted birds (Williams and Historically, the approach to resolving problems Colson 1989, APLIC 1996). Roosting and perching associated with roosting raptors was either to deter birds can cause power outages where their fecal birds from roosting over insulators or to shield the matter contaminates insulators (Michner 1928, insulators from fecal contamination (Michner Kaiser 1970, Sierra Pacific Power et al. 1988). The 1928). A comprehensive study in Idaho showed traditional solution to the problem was to remove that the combination of shields and pegging can nests (Stocek 1981). This is not a desirable solution be a positive and cost-effective approach to man- because of legal and political ramifications (Olen- aging bird contamination of insulators on high- dorffet al. 1981), It is also ineffective because birds voltage transmission lines (Young and Engel 1988, will often rebuild nests on the same or a nearby Engel et al. 1993). Although this study focused on structure (Stocek 1981, Steenhof et al. 1993). An- Common Ravens, results may have application to other approach is to discourage nesting, which is raptors (vultures) that roost communally on pow- often used in conjunction with other efforts to en- erline structures. Shields successfully protected hance nesting opportunities (Stocek 1981, Wil- central-string insulators from raven fecal contami- liams and Colson 1989, APLIC 1996). nation, and pegging effectively deterred ravens Nesting opportunities can be enhanced by relo- from roosting on outer portions of the tower cross- cating nests, modifying powerpoles and providing arms, Treatments did not repel ravens from roost- nesting platforms on the powerline structures (Sto- ing on traditional towers, and they did not move cek 1981, APLIC 1996) Relocating nests from pow- to other towers. The effort significantly reduced . erlines to nearby trees or nesting platforms has bird-powerline problems but allowed birds to con- been successful for Ospreys {Pandion haliaetus)\ tinue to roost on the towers. however, sometimes birds will nest on another structure on the line (Stocek 1981, Austin-Smith Literature Cited and Rhodenizer 1983). Pole modifications (lower- Austin-Smith, PJ- AND G. Rhodenizer. 1983. Ospreys, ing crossarms, wires and hardware so birds can Pandion haliaetus. Can. Field Nat. 97:315-319. safely nest on top of the pole) are apparently ef- Avian Powerline Interaction Committee (APLIC). fective but costly (Stocek 1981). The alternative to 1996. Suggested practices for raptor protection on pole modifications is to place the nest on a plat- powerlines: the state of the art 1996. Edison Electric form and raise it safely above the wires (APLIC Institute/Raptor Research Foundation, Washington, DC U.S.A. 1996). Although nest platforms have been used on pow- Benson, P.C. 1981. Large raptor electrocution and powerpole utilization: a study in six western states. Ph.D erlines since the 1940s, few quantitative studies as- dissertation, Brigham Young University, Provo, UT sessed their overall effectiveness (Olendorff et al. U.S.A. 1981). A 9-yr study on a new 500-kV transmission 1982. Prevention of Golden Eagle electrocution. . line in Idaho and Oregon by Steenhofet al. (1993) EA-2680 Res. Proj. 1002, Final Rep. Electric Power found that Golden Eagles and Ferruginous Hawks Res. Inst. Palo Alto, CA U.S.A. {Buteo regalis) apparently preferred the nesting Boeker, E.L. and P.R. Nickerson. 1975. Raptor electro- platforms and had higher success rates on plat- cutions. Wildl. Soc. Bull. 3:79-81. forms, Raptor and Common Raven (Corvus corax) Engel, K.A., L.S. Young, K. Steenhof and M.N. Ko- nesting success on transmission line towers was chert. 1992. Communal roosting ofCommon Ravens similar to, or higher than, that on surrounding nat- in southwestern Idaho. Wilson Bull. 104:105-121. ural substrates. In some cases, towers provided a , L.S. Young,J.A. Roppe, C.P. Wright and M. Mul- rooney. 1993. Controlling raven fecal contamination more secure nesting substrate. The transmission of transmission line insulators. Pages 10-14 in J.W. line provided an opportunity for raptors and ra- Huchabee [Ed.], Proc. Int. Workshop on Avian Inter- vens to nest in areas where they had not before. actions with Utility Structures. Electric Power Res. The line was likely responsible for an overall in- Inst. Palo Alto, CA U.S.A. crease in the number of breeding pairs, Steenhof Kaiser, G. 1970. The buzzard (Buteo) as a cause ofsingle et al. (1993) recommended that utility companies pole breakdowns in high-tension lines. Elektrotechnische — use platforms or tower modifications to safely at- Zietschrift ^A. 91:313—317. 42 Expanded Abstracts VoL. 33, No. 1 Michner, H. 1928. Where engineer and ornithologist ceedings of a workshop on raptors and energy devel- meet: transmission line troubles caused by birds. Con- opments. USDI, Fish andWildl. Serv., Boise, ID U.S.A. dor 50:169-175. Sierra Pacific Power, Bonneville Power Administra- Miller, A.D., E.L. Boeker, R.S. Thorsell and R.R. tion, Pacific Power and Light and Idaho Power A Glendorff. 1975. Suggested practices for raptor elec- 1988. joint utility investigation ofunexplained trans- trocution on powerlines. Raptor Research Founda- mission line outages. Electric Power Res. Inst. Final tion, Inc., Provo, UT U.S.A. Rep. 5735, Palo Alto, CA U.S.A. Nelson, M.W. 1982. Human impacts on Golden Eagles: Steenhof, K., M.N. Kochert andJ.A. Roppe. 1993. Nest- a positive outlook for the 1980s and 1990s. RaptorRes. ing by raptors and ravens on electrical transmission 16:97-103. line towers./. Wildl. Manage. 57:271-281. AND P. Nelson. 1977. Powerlines and birds of Stocek, R.F. 1981. Bird related problems on electric pow- prey. Pages 228-242 in R.D. Chancellor [Ed.], Proc. er systems in Canada. Can. ElectricalAssoc. Final Rep. ICBP World Gonf. on Birds of Prey. International Contract No. 110 T210, Montreal, Quebec Canada. Council for Bird Preservation, Cambridge, U.K. Williams, R.W. and E.W. Colson. 1989. Raptor associa- Glendorff, R.R., A.D. Miller and R.N. Lehman. 1981. tions with linear rights-of-way. Pages 173-192 in Proc. Suggested practices for raptor protection on power- Western Raptor Management Symposium and Work- — lines the state-of-the-art in 1981. RaptorRes. Rep. No. shop. Natl. Wildl. Fed., Washington, DC U.S.A. 4, Washington, DC U.S.A. Young, L.S. and K.A. Engel. 1988. Implications of com- and R.N. Lehman. 1986. Raptor collisionswith util- munal roosting by Common Ravens to operation and ity lines: an analysis using subjective field observations. maintenance of Pacific Power and Light Company’s Pacific Gas and Electric Co., San Ramon, CA U.S.A. Malin to Midpoint 500 Kv transmission line. Final Res GR Peacock, E. 1980. Powerline electrocution of raptors. Rep., Pacific Power and Light Co., Portland, Pages 2-5 in R.P. Howard and J.F. Gore [Eds.], Pro- U.S.A.