Minimizing bird collisions -
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Minimizing bird collisions -

Minimizing bird collisions: What works forthe birds and what works for the utility?John M. Bridges, Theodore R. Anderson, Dirk Shulund, LindaSpiegel, and Tim ChervickBird collisions with overhead wires have been reported in the United States at least since 1876. A number ofsolutions have been tried all with varying degrees of success. Raptor silhouettes, different color marker balls,“bird diverters”, “flappers” and various other devices to warn birds all work to some degree. However,depending on the target species and the object being marked, if you use the wrong type or color of device itmay not be effective, could result in a maintenance problem, or may even cause lines to go down. To date,there is very little published empirical data on which device works for which species or group of species.Anecdotal information suggests that some things do not work as well for some bird species as they do forothers. This paper will discuss the mitigative measures found in the literature and provide a brief evaluationof their effectiveness and some of the problems they may create. It will also discuss some of the on-goingresearch, including the effects of motion and light, where information is available. Evaluation of markingdevices will be based on existing literature, the experience of line crews and personal experience.Keywords: Bird collisions, power lines, line marking devices, bird diverters, flappersINTRODUCTIONBird collisions with overhead wires are a global issue. They have been noted as a cause of mortality in the United States atleast since 1876 (Coues 1876). Avery (1978) summarized the issue of bird collisions with transmission lines for the U.S.Fish and Wildlife Service. Faanes (1987) examined bird flight behavior in the presence of transmission lines in the northernGreat Plains of the U.S.; Telfer, et al. (1987) discussed bird collisions in Hawaii; Ledger, et al. (1993) discussed collisionsin South Africa; Bevanger (1993) compared ptarmigan (Lagopus lagopus) collision mortality with hunting mortality inNorway; Boyd (1961) reported on collisions of banded waterfowl in Great Britain; Alonso et al (1993) and Roig andNavazo (1997) describe collisions in Spain; Hess (1999) is working on the problem in Australia; and De La Zerda andRosselli (2002) describe some of the problems in Columbia. Additionally, there are numerous articles dealing with birdcollisions in both peer reviewed journals and the popular press (see California Energy Commission 1995 and 2002). Birdmortality due to collisions with a single transmission line, is not generally considered not biologically significant (Fannes1987, and Hugie et al. 1993). However, as Brown (1993) pointed out, cumulatively, bird deaths due to collisions, combinedwith other forms of mortality (e.g. habitat loss and fragmentation) can result in significant effects to a population.Additionally, some lines, such as those crossing wildlife refuges, may have more significant impacts than currentlyunderstood due to inadequate survey efforts.Birds collide with transmission lines because of hampered visibility or because they are occupied by something elsesuch as courtship, hunting, or escape. Decreased visibility due to inclement weather can result in a higher incidence of collisions(Krapu 1974). Incidence of collisions tend to increase during spring mating season and again during the late summer and fallwhen young of the year are learning the intricate maneuvers of flight (Hugie et al. 1993). Panic flushes also result in collisions,particularly of flocking birds (e.g. waterfowl, wading birds, or shorebirds) (Krapu 1974, and Schroeder 1977). Some species aremore susceptible to collisions than other species. Crowder and Rhodes (2002) related this in part to the ratio of wing aspect towing loading.MINIMIZING COLLISIONSThe Avian Power Line Interaction Committee has summarized the methods used to reduce collisions (APLIC 1994). Theseinclude careful location of the line when originally routed. If the line is already in place, a two-year, four-season, study isrecommended to determine if a collision problem exists, what the aerial extent of the problem is, what species are involvedand where on the line the collisions occur. Based on the results of the study, the problem may be minimized by removingthe overhead ground wire, if that is where the collisions occur, and when it is appropriate, and/or marking the lines withsome type of device to make them more visible. Marking devices include aviation marker balls, spiral vibration dampers,air flow spoilers, bird flight diverters of various designs and dimension, and several devices that have movement such asswinging plates or flappers.1

Obviously the best way to minimize bird collisions with transmission and distribution lines is avoidance of the situation.That is, in the initial planning stages of a new line, stay away from areas where birds tend to congregate. These include feedingand loafing areas, the communication flyways between them, as well as migratory staging areas, particularly wetlands and rivers.Unfortunately, avoidance is not always practical due to engineering, environmental or economical constraints. Although it isgenerally impractical if the line is already in place, in some cases problem lines have been relocated.In the last 20 years, increased efforts have gone into finding the best methods of dealing with existing lines that areknown to have bird collisions. Two international workshops on the subject of birds and the electric utility industry have beenheld in the United States since the early 1990’s. Several others have been held in South Africa, the Middle East, and Europe. Tounderstand how to make an object more visible to birds, we must first understand how a bird views its environment and how itreacts to that visual input (see Cook 2001). Obviously most birds are dependent on vision for mating and feeding. One has but tolook at the coloration of breeding plumage or the hunting techniques of raptors, vermivores or carrion feeders.According to Faanes (1987), most bird collisions in his study occurred with the overhead ground wire when the birdsveered up to avoid the conductors. Beaulaurier et al. (1984) found that removing the overhead groundwire or shield wire wasvery effective in the Pacific Northwest. However in areas that experience a lot of lightning, this would leave major transmissionsystems exposed to numerous outages. Additionally, there are studies that infer the ground wire is not the cause for collision inevery instance (Anderson 1978 and Krapu 1974). Meyer (1978) found marking the overhead groundwire works with varyingdegrees of success. APLIC (1994) lists the effectiveness of various line marking devices (i.e., 12-inch marker balls, spiralvibration dampers and bird flight diverters) with a range of 40 to 89 percent, depending on device and spacing on the lines.Brown and Drewien (1995) studied the effectiveness of different marking devices (i.e., swinging plates and spiral vibrationdampers) and they found the marking devices resulted in changed flight behaviors and reduced collisions (by 63 percent and 61percent, respectively). However they reported the effectiveness varied by device, season and species. The swinging plate hadsome initial problems with the clamp. The clamp moved slightly in strong winds and began to wear on the wires. Crowder (2000)reviewed the relative effectiveness of bird flight diverters and swan flight diverters. He reported that bright colored (yellow) birdflight diverters were better at reducing collisions than gray (76 percent to 58 percent) but the gray swan flight diverters weremore effective than yellow (44 percent to 25 percent). Roig and Navazo (1997) found that “white spirals” spaced every 10 meterson the overhead ground wire were effective. Where overhead ground wires were not present, they attached a 35 centimeter long,black, neoprene strip to the conductor and that worked almost as well. Koops and de Jong (1981) studied the effectiveness of“bird flight diverters” in Denmark and found that, depending on the spacing of the diverters on the wires, they reduced birdcollisions by 57 to 89 percent. Telfer (1999) found that bird flight diverters had little effect on shearwater (Puffinus sp.)collisions, but yellow aviation marker balls with 8-inch black dots worked quite well. Beaulaurier et al. (1984) also used orangeaviation marker balls, fishing floats and yellow streamers, all with some success. Bird flappers, a device that attaches to either thegroundwire or conductor, have been suggested by Miller (1993) and Ledger et al. (1993). Van Rooyen (2003) placed flappers onlines in South Africa and found them to reduce bird collisions. Janss et al. (1999) found the use of raptor models (i.e. eaglesAquila sp. and Accipiters) mounted on transmission line structures, to reduce collisions. They found that the models had no effecton collisions or the potential for collisions.More recent studies and reports on bird vision have led to the development of devices that work in the wavelength thatbirds use and have motion that catches bird’s attention. Birds use motion to detect and hunt for food, and avoid predators. Somebirds have the ability to define and distinguish patterns and objects using only motion information (Dittrich and Lea 2001).Hawks, penguins and insectivorous birds are strictly dependent on motion cues for detecting prey at great distances. Many birdspecies have the ability to see at two peak wavelengths of light (Springsteen, 2003). One peak wavelength, 560 nanometers (nm)or yellow color, is shared with humans in the visible light range. The other peak wavelength of light, 360 nm wavelength, whichis in the A-band of ultra-violet light, is found in sunlight and is invisible to humans. McGraw (2004) states that color signaling bybirds play an important function in locating and acquiring food, attracting mates, mediating aggressive behavior, and avoidingpredation. The complex retina and sensitive vision of birds surpass those of most animals (Hart 2001). Bird feathers reflect lightwithin the multilayered arrangement of feather barbs and barbules, causing iridescent effect in some bird feathers. This iridescentcolor may function in important signaling within different bird species (McGraw 2004). According to Husband and Shimizu(2001), birds appear to have excellent color vision which may be based on their having four or five photo pigments, compared tothree in primates. This may explain the success Telfer (1999) had with marking lines with yellow marker balls that he paintedwith large black spots. However, as Janss et al. (1999) found when using raptor models to haze birds not all birds interpret awarning device as a warning. Smaller birds tended to harass the models.At this time there are several studies underway to test the efficacy of the devices to warn birds of objects in the air. RedElectrica de Espana is testing devices on some of its lines (Roig 2004). Eskom is also testing the “flapper” on flamingos and bluecrane collisions in South Africa (Van Rooyen and Smallie 2003). They found the flappers reduced flamingo collisions by 82percent and blue crane collisions by 84 percent. There is also a consortium of partners developing the technology to test linemarking devices and monitor bird activity for projects in North Dakota and California (California Energy Commission 2003).The Technical Advisory Group for this study includes three agencies in the U.S. Department of Interior, two agencies in the U.S.Department of Energy, two agencies in the U.S. Department of Agriculture, one agency in the U.S. Department of Commerceand one in the Department of Defense. There are electric utilities, environmental organizations and interested individuals fromfive continents also participating. Several state agencies along with EPRI, Inc. and the Avian Power Line Interaction Committeeare also involved.2

CONCLUSIONSWith all of these techniques, it is important to remember that the purpose of the wire is to aid in the reliable delivery ofelectricity. The amount of lightning activity has to be considered before removing the overhead groundwire. Aviationmarker balls and anything else placed on a line, tend to accumulate ice and snow in northern latitudes and at higheraltitudes. As one might expect, the bigger the device the more weight will be added to the line. Ice- and wind-loadingpotential need to be evaluated before attaching anything to either the conductors or the groundwires. Design engineers cananswer questions on the ability of the line to bear up under the additional weight of the marking device, especially with theadded weight of ice and/or snow. The same is true for wind loading. Aeolian wind dampers are used on distribution andsub-transmission lines to minimize the adverse actions of wind (i.e., galloping or slapping). These may be useless if adevice with a large surface area is attached to the line or shield wire. Additionally, the clamp that attaches the device to theconductor or the shield wire, whether it is an aviation marker ball, spiral bird-flight diverter or flapper may also wear on thewire it is attached to, resulting in failure of the wire. Another engineering issue associated with marking devices is coronadischarge, which can result in audio noise, radio or television interference, create safety issues, or impede the flow ofelectricity. The California Energy Commission and the Western Area Power Administration are currently funding researchto determine the corona discharge of several marking devices at various voltages. And finally, whatever mitigation isapplied needs to be reviewed periodically to ascertain its effectiveness (no one device will work for every situation) anddetermine the need for repair and/or replacement. If that need arises too frequently, the maintenance of the device and ofthe line may become too costly, and these costs are passed on to the users.REFERENCESAlanso, J.C., J.A. Alanso, R. Munoz-Pulido, J. Roig, V. Navazo and J. Arevalo. 1993. Senalizacion de lineosdealta tensionpara la proteccion de la avifauna. Red Electrica de Espana, S.A. 58p.Anderson, W.L.. 1978. Waterfowl collisions with power lines at a coal-fired power plant. Wildl. Soc. Bull.6:77-83.Avery, M. T. (ed). 1978. Impacts of transmission lines on birds in flight. U.S.D.I. Fish and Wildlife Service. FWS/OBS-78/48. 151p.Avian Power Line Intreraction Committee (APLIC). 1994. Mitigating bird collisions with power lines: the state of the art in1994. Edison Electric Institute, Washington, D.C. 103p.Beaulaurier, D. L., B.W. James, P.A. Jackson, J.R. Myers, and J.M. Lee, Jr. 1984. Mitigating the incidence of birdcollisions with transmission lines. P 539-550. In A.F. Crabtree (ed). Proceedings of the Third International Symposiumon Environmental Concerns in Rights-of-Way Management. Mississippi State Univ., MS. 689p.Bevanger, K. 1993. Hunting mortality versus wire-strike mortality of willow grouse (Lagopus lagopus) in an upland area ofsouthern Norway. P11-1 – 11-10. In APLIC. Proceedings: Avian Interactions with Utility Structures InternationalWorkshop. EPRI, TR-103268 (Project 3041), Palo Alto, CA.Boyd, H. 1960. Reported casualties to ringed ducks in the spring and summer. Wildfowl Trust 12:144-46.Brown, W. M. 1993. Avian collisions with utility structures: biological perspectives. P12-1 – 12-13. In APLIC.Proceedings: Avian Interactions with Utility Structures International Workshop. EPRI, TR-103268 (Project 3041), PaloAlto, CABrown, W. M. and R.C. Drewien. 1995. Evaluation of two power line markers to reduce crane and waterfowl collisionmortality. Wildlife Soc. Bull. 23:217-227.California Energy Commission. 1995. Avian collision and electrocution: an annotated bibliography. Sacramento, CA.P700-95-001.California Energy Commission. 2002. A roadmap for PIER research on avian collisions with powerlines in California.Sacramento, CA. P500-02-071F.California Energy Commission. 2003. Bird Strike Indicator/Bird Activity Monitor and Field Assessment of AvianFatalities. Sacramento, CA. 500-03-107F.Cook, R.G. 2001. Avian visual congintion. [On-line]. Available: Downloaded 6/12/2004.Coues, E. 1876. The destruction of birds by telegraph wire. American Naturalist 10(12):734-36.Crowder, M. R. 2000. Assessment of devices designed to lower the incidence of avian power line strikes. Master of ScienceThesis, Purdue University, East LaFayette, IN. 91p.Crowder, M.R. and O.E. Rhodes, Jr. 2002. Relationships between wing morphology and behavioral responses to unmarkedpower transmission lines. P.403-410. In J.W. Goodrich-Mahoney, D.F. Mutrie and C.A. Guild (eds). The SeventhInternational Symposium on Environmnetal Concerns in Rights-of-Way Management. 9-13 September, 2000. Calgary.AB, Canada. Elsevier Publ. Co. Oxford, UK. 955p.De La Zerda, S. and L. Rosselli. 2002. Mitigating collision of birds against transmission lines in wetland areas in Columbiaby marking the ground wire with bird flight diverters (BFD). P. 395-402. In J.W. Goodrich-Mahoney, D.F. Mutrie andC.A. Guild (eds). The Seventh International Symposium on Environmnetal Concerns in Rights-of-Way Management.9-13 September, 2000. Calgary. AB, Canada. Elsevier Publ. Co. Oxford, UK. 955p.3

Dirk ShulundWestern Area Power Administration, P.O. Box 35800, Billings, MT. 59107, USA. Telephone:406-247-7402,Fax:406-247-7408, Shulund is an Environmental Protection Specialist for the Western Area Power Administration’s Upper Great PlainsRegional Office. He has worked for Western for nearly 5 years. He is responsible for implementing the NationalEnvironmental Policy Act and coordinating cultural resource and natural resource consultations for projects in Western’sUpper Great Plains Region. He holds a BS degree in Environmental Science and is working on a Masters in EnvironmentalStudies.Linda SpiegelCalifornia Energy Commission, 1516 Ninth Street, Sacramento, CA 95814, USA Telephone: 916-654- 4703 E-mail: Spiegel has been working as wildlife biologist for 22 years and for the Energy Commission for 16 years. Herexperience includes assessing biological impacts from energy-related facilities, and conducting or overseeing research toresolve these impacts. She currently oversees numerous research projects relating to understanding and/or mitigating avianfatality from electrocution with power poles and collisions with power lines and wind turbines.Timothy ChervickSwift Creek Consulting, 152 North Sun Arbor Terrace #2048, Salt Lake City, UT 84116, USA. Telephone: 801-981-8102, Fax: 801-981-8132. E-mail: timothychervick@comcast.netMr. Chervick is the President of Swift Creek Consulting, Inc., which provides environmental consulting services to theenergy industry in northwest Colorado and northeastern Utah. Mr. Chervick has a BS degree in Wildlife Management andConservation from the University of Wyoming in 1973. He has worked in water quality and biology for over 20 years. Mr.Chervick has been actively involved with raptors for over 35 years and currently holds a U. S. Fish & Wildlife ServiceMaster Falconry license within the state of Utah. He has invented products for the electric utility industry, including VernalTriangle perch guard, which was designed and field-tested in 1995 and has a patent pending for the “firefly flapper” adevice to warn birds of obstructions and to haze birds from electrical equipment.5

CONTACT LIST:#1. John M. Bridges, A7400Western Area Power AdministrationP.O. Box 281213Lakewood, CO 80228-8213(720)962-7255#2. Ted Anderson, B0400.BLWestern Area Power AdministrationP.O. Box 35800Billings, MT 591070-5800(406)247-73856

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