Note: This is a manuscript, currently in press, of a speech presented by Al Manville at the Avian Interactions Workshop held December 2, 1999, in Charleston, SC, and sponsored by the Electric Power Research Institute. The paper provides a detailed overview of the communication tower/bird strike problem. The manuscript is being published in the Proceedings of the Avian Interactions Workshop. For purposes of copyright protection, should the document be cited, please use the following reference:
Manville, A. M. II. 2000. The ABCs of avoiding bird collisions at
communication towers: the next steps. Proceedings of the Avian Interactions
Workshop, December 2, 1999, Charleston, SC. Electric Power Research Institute
THE ABCs OF AVOIDING BIRD COLLISIONS AT COMMUNICATION TOWERS: THE NEXT STEPS.
ALBERT M. MANVILLE, II, Ph.D. Wildlife Biologist, Division of Migratory Bird Management, U.S. Fish and Wildlife Service, 4401 N. Fairfax Dr., Suite 634, Arlington, VA 22203, USA. Phone: 703/358-1714; e-mail: Albert_Manville@fws.gov
Abstract: Published accounts of avian collisions with tall, lit structures date back in North America to at least 1880. Long-term studies of the impacts of communication towers on birds are more recent, the first having begun in 1955. This paper will review the known and suspected causes of bird collisions with communication towers (e.g., lighting color, light duration, and electromagnetic radiation), assess gaps in our information base, discuss what is being done to fill those gaps, and review the role of the U.S. Fish and Wildlife Service (FWS or Service) in dealing with this important problem. This paper will also review avian vulnerability to collisions with tall structures, currently affecting nearly 350 species of neotropical migratory songbirds that breed in North America in the spring and summer and migrate to the southern United States, the Caribbean, or Latin America during the fall and winter. These species generally migrate at night and appear to be most susceptible to collisions with lit towers when foggy, misty, low-cloud-ceiling conditions occur during their spring and fall migrations. Thrushes, Vireos, and Warblers are the species that seem the most vulnerable. Lit towers, those exceeding 199 feet (61 m) above the ground, currently number about 46,000 in the United States (not including lit "poles"), with the total number of towers registered in the Federal Communications Commission database listed at some 75,000. Also included in this paper are preliminary voluntary recommendations designed to help minimize bird collisions with towers, as well as a review of activities that prompted recent FWS action in dealing with this issue. This paper will further review two partnerships with the electric utility and electric wind generation industries -- the Avian Power Line Interaction Committee and the National Wind Coordinating Committee's Avian Subcommittee, respectively -- as possible models for a future partnership with the communication industry (i.e., radio, television, cellular, and microwave).
Key words: Avian mortality, bird watching, bird strikes, collisions, communication towers, guy wires, habitat management, lights, mitigation, neotropical migratory songbirds, night migrations, radio frequency waves, partnerships, tower siting.
Published accounts of birds striking tall, lit structures such as lighthouses -- although often anecdotal -- have appeared in the scientific literature since at least 1880 (Crawford and Engstrom 1999). The earliest known published report of a bird-tower kill in the United States took place in September 1948 at a 450-foot (137-m) radio tower in Baltimore, Maryland, although no details about the incident were made available (Aronoff 1949). The first long-term study of the impact of a television tower on birds was begun in 1955 by the Tall Timbers Research Station in northern Florida. With the ground conditions and the number of scavengers controlled as much as possible, daily searches for dead birds were made under this tower. Kills were plotted on maps, weather records were maintained, and dead birds were speciated. After the first 25 years, 42,384 birds representing 189 species were tallied (Crawford and Engstrom 1999). The longest study yet conducted was by physician Charles Kemper over a 38-year period, beginning in 1957 (Kemper 1964, 1996). He collected 121,560 birds representing 123 species. On one night in 1963, he collected and speciated over 12,000 birds, the largest single-night kill yet documented, not accounting for the almost certain scavenging by wild and domestic predators such as crows (Corvus brachyrhynchos), owls (Strigidae), foxes (Vulpes vulpes), dogs (Canis familiaris), cats (Felis domesticus), and others then present. Other studies also have been conducted on the effects of tall towers on nocturnal bird migrations, most notably by Avery et al. (1976) at a U.S. Coast Guard Omega Navigation Station in North Dakota using a portable ceilometer.
In fact, since the 1970s there has been much information published about bird strikes with communication towers. A good deal of this information has been maintained by Division of Migratory Bird Management (DMBM) web sites at http://www.fws.gov/ r9mbmo/homepg.html and http://migratorybirds.fws.gov/issues/towers/agenda.html.
Unfortunately, most of the research that has been done regarding bird strikes with these structures only reviews carcass counts and species variability, not the presumed or suspected causes of bird collisions. Research into this arena is sorely lacking. Published accounts do, however, answer one question. Birds vulnerable to communication towers comprise some 350 species of so-called neotropical migratory songbirds. Of these, Thrushes (Muscicapidae), Vireos (Vireonidae), and Warblers (Parulidae) are the species that seem the most vulnerable. These migratory songbirds are species that breed in North America in the spring and summer and migrate to the southern United States, the Caribbean, or Latin America during the fall and winter. These species also generally migrate at night and appear to be most susceptible to collisions with lit towers on foggy, misty, low-cloud-ceiling nights during their migrations. Lights seem to be key.
Federal Trust Responsibility
Migratory birds are a trust resource for the U.S. Fish and Wildlife Service. The Service is currently responsible for the conservation and management of 836 species of migratory birds protected by the Migratory Bird Treaty Act (MBTA) of 1918, as amended (16 U.S.C. Sections 703 and 712; Sections 704-712 authorizing the Secretary of Interior to issue implementing regulations). Of these, 778 are categorized as so-called nongame species (e.g., the Eastern Bluebird [Sialia sialis]), while 58 species are legally hunted as game (e.g., the Wood Duck [Aix sponsa]). The Service is currently faced with a dichotomous challenge: while the populations of some species are doing very well -- some too well (e.g., the mid-continent lesser Snow Goose [Anser caerulescens caerulescens], the urban Canada Goose [Branta canadensis], the Brown-headed Cowbird [Molothrus ater], and the Double-crested Cormorant [Phalacrocorax auritus]) -- many other species are not (Schmidt and Petit 1998). We currently are seeing the continuing declines of over 200 species. Of these, 90 are listed under the Federal Endangered Species Act (ESA) of 1973, as amended (16 U.S.C. 1531 et seq.): 75 species are listed as Endangered, such as the Whooping Crane (Grus americana); while 15 species are listed as Threatened, such as the San Clemente Sage Sparrow (Amphispiza belli clementeae). Another 124 are on the Service's list of Nongame Species of Management Concern (e.g., Cerulean Warbler [Dendroica cerulea]; Trapp 1995). These include birds whose populations are declining, some precipitously. If trends are not reversed, the next likely step is listing under ESA -- a train wreck we would prefer to avoid. Add to the known declines our lack of population data on many of the bird species. Fully one-third of the 836 species (some 279) have essentially no population data.
Before attempting to assess the impacts of communication towers (including -- but not necessarily limited to -- radio, television, cellular, microwave, paging, messaging, open video, public safety, wireless data, government dispatch, and emergency broadcast) on birds, first look at the other non-tower factors that kill birds. Mortality occurs from collisions with wind generators, electric transmission and distribution lines, glass windows, aircraft, and automobiles; electrocutions; oil and contaminant spills; pesticide poisonings; predation by cats; introductions of exotic species; habitat loss and/or degradation; and other causes. Although their estimates are conservative to very conservative, some of these impacts illustrate the relative magnitude of these threats to avian survivorship. For example, building window collisions are estimated to take from 97 to 970 million birds per year, or from 1 to 10 birds per building annually in North America (Klem 1989, 1990; O'Connell 1998). In one study, pesticide ingestion was estimated to kill 65 million birds per year (Pimentel et al. 1992). Kill figures alone from birds retrieved from Alaska's Exxon Valdez oil spill were huge. As of September 1989, over 36,470 dead birds were retrieved for evidence by the FWS, representing 90 different species (Manville 1991). Estimates for oil-caused avian mortality from the Exxon spill ranged from 350,000-500,000. Another source of bird mortality is free-ranging domestic cats. Nationwide, these felids are estimated to kill hundreds of millions of birds - an astounding impact. In one four-year study in Wisconsin alone, domestic cats were estimated to kill roughly 39 million birds each year (range 8-217 million) in just the rural areas of that State (Coleman et al. 1997).
Add to this the growing impacts of communication towers whose construction is occurring at an exponential rate -- conservatively estimated at 4-5 million birds killed per year due to collisions with communication towers (Manville 1999) -- and the cumulative impacts of all these mortality factors is of grave concern. While, for example, it may be difficult to seriously reduce window strike and automobile mortalities, many feel we can take substantive steps to reverse trends in bird-tower collisions. It is incumbent upon us to do whatever possible to reverse these trends.
Birds are big business in North America. In 1996, for example, some 63 million Americans 16 years old and older enjoyed activities such as feeding, photographing, and watching birds. These wildlife watchers spent an estimated $28.9 billion pursing these activities (USFWS 1997; Fenwick 1997). With perhaps the exception of gardening, birdwatching has become America's fastest growing hobby, increasing 150% over the past decade. More Americans reportedly go on vacations to watch birds today than to play golf. In the 1994-95 National Recreation Survey, for example, birdwatching had increased 155% over the previous decade compared to a 29% increase for golf (Stangel and Fenwick 1997).
From a utilitarian standpoint, birds pollinate flowers and remove insect pests from many important commercial food crop and forest species, making possible a multi-billion-dollar industry extremely dependent upon birds for its success. One pair of Warblers, for example, will remove the defoliating caterpillars from more than 1 million leaves within the 2-3 week period that they are feeding their nestlings. In the Pacific Northwest, 24 species of neotropical songbirds feed on the western spruce budworm (Choristoneura occidentalis) and the Douglas fir tussock moth (Orgyia pseudotsugata), two of the most destructive defoliating insects found in the region. Birds remove countless weed seeds -- including exotic species -- that compete for food crop and forest production. Birds also distribute seeds of important forest tree and shrub species whose survival would not exist without bird seed dispersal. The global reduction of pollinators -- including birds -- raises alarm. Fully two-thirds of our flowering plants are pollinated by birds, insects, and bats, producing a global economic benefit estimated at $117 billion per year (Smithsonian Migratory Bird Center 1994; Ornithological Council 1997). In short, birds are extremely important to us all.
Fish and Wildlife Service Involvement
The Service has played other and more historic roles than those dealing with bird strikes in the siting and placement of communication towers. Through the Service's Division of Habitat Conservation, Fisheries and Habitat Conservation, and our Ecological Service field offices, we review siting requests and potential problems created by towers as mandated by the National Environmental Policy Act of 1969, as amended (42 U.S.C. 4321 et seq.), and Section 7 of the ESA. It was only more recently that DMBM became actively involved in the tower-collision issue. On January 22, 1998, a large kill of an estimated 5,000-10,000 Lapland Longspurs (Calcarius lapponicus) -- a migratory songbird -- occurred at and in the vicinity of three communication towers and a natural gas pumping facility in western Kansas on a snowy, foggy night. Almost immediately, the issue was brought to DMBM's attention by various representatives of the environmental community, most notably the National Audubon Society, the American Bird Conservancy (ABC), and the Ornithological Council (OC). In April 1998, I was asked on behalf of DMBM to brief the Policy Council of ABC on, among other things, bird mortality from communication tower strikes. At the time, a partial but certainly not complete list of reviewed and abstracted literature was provided to the Council. Following this briefing, informal discussions continued between representatives of the Federal Communications Commission (FCC), the Service's Division of Habitat Conservation, and DMBM.
On November 17, 1998, representatives of the Service's regional, field, and Washington, DC, offices met in Panama City, Florida, to discuss, "Migratory Bird Conservation and Communication Towers: Avoiding and Minimizing Conflicts." That document was subsequently made available to the public (Lang 1999). In December 1998, I and another FWS staff member met with representatives of the environmental dispute resolution group, RESOLVE, to discuss the need for a facilitated meeting with stakeholders to review and discuss research needs and gaps, put concerns over bird kills on the table, and begin a dialogue with the various players. That facilitated meeting, attended by 42 stakeholders, took place on June 29, 1999, at RESOLVE in Washington, DC. Those agencies represented included the FCC, the Federal Aviation Administration (FAA), the Federal Highway Administration, the U.S. Department of Agriculture's National Wildlife Research Center, the Service, and the Wisconsin Department of Natural Resources. Those from the research community included the Illinois Natural History Survey, the Buffalo Museum of Science, Geo-Marine, the State University of New York at Geneseo, Cornell University, Clemson University, and Curry & Kerlinger. Industry representatives included the Cellular Telecommunications Industry Association, Environmental Resources Management, Motorola, the Personal Communications Industry Association, SBC Wireless, and Southwestern Bell Wireless. Environmentalists were represented by ABC, the National Audubon Society, the OC, and the Piedmont Environmental Council. The most substantive result of the meeting was the creation of the Communication Tower Working Group with 15 individuals agreeing to participate. The Working Group's purpose is to develop and implement a research protocol that will determine what about towers kills birds. DMBM was asked to chair the Working Group.
On August 11, 1999, the very first public workshop on "Avian Mortality at Communication Towers" was held at Cornell University in conjunction with the 117th meeting of the American Ornithologists' Union. The workshop was co-sponsored by the Service, ABC, and the OC. Bill Evans, an independent ornithological researcher from Ithaca, New York, and I - representing the Service - co-chaired the meeting which included presentations by 17 speakers, and a discussion on research and funding needs, information gaps, and next steps by a panel of 23 experts. Complete transcripts of the meeting are available on <http://migratorybirds.fws.gov/issues/towers/agenda.html> and on <www.towerkill.com>. Much information, some of which has previously been summarized in this paper, was presented in the workshop. The representative from the FAA, for example, pointed out that all towers more than 199 feet (61 m) above ground level (AGL) must contain a pilot warning light(s). Based on the July 2000 FCC Antenna Structure Registry database, there were some 46,000 lit towers more than 199 feet AGL (not including towers classified as "poles") in the United States. Approximately 75,000 towers (including some 23,000 which are not lighted) are now listed in the FCC's database. Some groups have argued that the database understates the true number of lit towers, suggesting that upwards of 80,000 towers are currently lighted. Whatever the correct figure, we do know that tower siting and construction have increased exponentially within at least the last 3 years and that growth continues at 6-8% per year.
Known and Suspected Problems
What is it specifically about towers that seems to attract birds? Lighting, again, is critical. As bird attractants, lights on tall structures have been cited in the literature well back into the early 1900s and before (Crawford and Engstrom 1999). Cochran and Graber (1958) were among the first to document lighting impacts on birds. They noted that when tower lights were turned off, the number of migrant flight calls decreased significantly, but within minutes after the tower was relighted, flight calls "increased dramatically." Inclement weather conditions are usually necessary, as reported by Laskey (1954), and mass bird kills seem to be related to either white or red lighting as reported by Avery et al. (1976). Large bird kills, however, do not always occur during inclement weather, as evidenced by a kill of some 450 songbirds (30 species involved, most notably 145 Yellow-rumped Warblers [Dendroica coronata], 114 Orange-crowned Warblers [Vermivora celata], and 37 Nashville Warblers [V. ruficapilla] at a red blinking television tower near Topeka, Kansas, in early October 1999. The skies were clear until approximately 3:00 am the night of the tower kill (Stephanie Jones, FWS, 1999 pers. comm.). How many birds died during the clear weather conditions before 3:00 am is unknown.
The retina of the bird's eye is far more sensitive to the red and infrared spectra than is the human eye. Color perception in birds is far more complex than in humans, as birds eyes contain 4-6 types of cones (color receptors) while human eyes contain only 3 types. Light can affect birds' behavior both visually and magnetically. All bird species thus far examined have been shown to have a narrowly tuned receptor in the red region of the electromagnetic spectrum (Beason 1999). Although research in this area is lacking, birds may be attracted to red lights or become disoriented by having red lights disrupt their magnetic compasses. Color (i.e., white, white with ultraviolet, and specific colors such as red) and flash duration (i.e., strobed, slow flash, or steady) are two aspects of lighting that can change its attraction for birds (Beason 1999). A few reports indicate that white strobe lights, whose ultraviolet content is unknown, are less attractive to birds than steady or flashing red lights (Gauthreaux and Belser 1999).
Is the bird's navigation system disrupted by the red lighting or is the bird's ability to monitor the geomagnetic field disrupted by the radio frequency signal itself? Long wavelength illumination, such as that in the red-orange spectrum, has been shown to interfere with the avian magnetic compass (Beason 1999). However, current thinking seems to indicate that light flash duration, rather than color, is far more critical. The longer the "off" phase between the blink or flash phases of the light pulses, the less likely birds are to be attracted to the lighting (Michael Avery, USDA, 1999 pers. comm.). For example, solid or blinking red lights seem to attract birds on foggy, misty nights far more often than do white strobes, which may flash once every 2-3 seconds (3 seconds currently the maximum allowable "off" duration). Again, the "off" phase of the light seems critical, the longer that phase the less likely the attraction during foggy, misty, rainy, overcast, low-cloud-ceiling nights. While some preliminary research by Michael Avery, Robert Beason, and Sidney Gauthreaux supports this hypothesis, it will need further testing in a more systematic and statistically significant way.
While Avery et al. (1976) reported no noticeable effect of a Coast Guard navigation tower's signal on birds, they concluded that the tower's possible signal effect on birds could not be completely dismissed. Beason (1999) indicated that most radio frequency (RF) signals have no effect on avian orientation, with the exception of tracking radars. Pulsed microwave signals resulted in changes in the rate of spontaneous activity of neurons in the avian brain. Whether these changes resulted in behavioral effects (e.g., disorientation) is unknown (Semm and Beason, unpublished data in Beason 1999). While some have suggested the need for further RF research on birds, the literature does not support this suggestion (Bruderer and Boldt 1994; Bruderer et al. 1999).
The taller the tower, the more likely it will kill birds. As tower height increases, so often does the number of guyed, supporting wires. Guy wires are critical in their effects on birds. The greater the number of guys (which often are tiered in bands of 3-4 wires per level), the more risk of bird strikes. Here's how the problem seems to arise. On nights of inclement and overcast weather when songbirds are active in broad-front migrations, lights seem to draw birds into the towers. This has been reported by many observers (e.g., Avery et al. 1976) when celestial cues are not available to birds flying below the cloud ceiling. Perhaps the birds mistake the light(s) for stars or the sun. Graber (1968) reported that birds entering an illuminated area on cloudy nights were reluctant to leave the lit area, just as birds in a lighted room will not fly out an open window into the darkness. Approaching the edge of the illuminated area, migrants are hesitant to fly into the darkness beyond the tower, and instead fly back toward the tower (Avery et al. 1976). Once attracted to the lights, they fly around the tower in a "tornado" of birds, striking the guy wires directly in the path of flight, the tower, themselves, or the ground, and often die.
A worst-case tower scenario might look like the following. The structure in question would be a 1,000-plus-foot (304-plus-m), multiple-guyed, multiple solid-lighted tower situated next to a wetland, within a known songbird migration corridor, with the presence of several Federally listed endangered songbirds documented in and around the area, in a location with a history of fog, especially during the spring and fall. This scenario, unfortunately, is by no means impossible. The Telecommunications Act of 1996 (Public Law 104-104), in fact, mandates that all television stations be digitized by no later than 2003. By some estimates, this mandate could result in the addition of 1,000 new, 1,000-plus-foot "mega-towers" across the landscape in the United States. However, the MBTA of 1918, as amended -- our "marching orders" for DMBM -- is a strict liability law. The Act does not allow the killing or taking of migratory birds, except by permit, and the Service does not issue incidental take permits. Thus, the incidental killing of even one bird is legally considered a taking under MBTA and is technically a violation of the law. Concerning their mandates, the Telecommunications Act and MBTA may, thus, be directly at odds. Taking these issues into consideration, the Service recommends that communication companies do whatever they can to prevent needless bird deaths.
While the Service recognizes that research into the actual causes of bird collisions with communication towers is scant, some preliminary but promising findings -- previously mentioned -- provide insight into ways of minimizing or even avoiding bird collisions with towers. In an effort to provide significant protection for migratory birds, and until research efforts uncover significant new mitigation measures, the Service has been suggesting to industry voluntary interim guidance in the siting and placement of towers. While these recommendations are discretionary and non-binding to both Service personnel and to the public, they have been approved by the Director. Here is what the Service suggests. For companies planning to site, construct, and operate new towers, we encourage the following:
1. Any license applicant proposing to site a new communication tower is strongly encouraged to collocate the proposed communication equipment on an existing communication tower or related existing structure (e.g., a church steeple, billboard mount, water tower, electric transmission tower, monopole, or building). With Crown Castle International, for example, 9 tenants on average collocate on towers they own around Pittsburgh, Pennsylvania; and as many as 120 tenants can collocate on a tower (Powers 2000).
2. If collocation is not practical, license applicants are strongly encouraged to construct towers less than 200 feet (61 m) AGL, using construction techniques that do not require guy wires (e.g., lattice or monopole structures). Such towers do not require lighting under FAA regulations unless located within 3.8 miles (6.1 km) of airports and near major travel corridors, and so should not be lighted unless required. If at all possible, new towers should be located within existing "antenna farms," preferably in areas not used by migratory birds or species Federally or state-listed as endangered or threatened, or listed as Nongame Species of Management Concern (Trapp 1995). Avoid siting towers in or near wetlands, near other known bird concentration areas (e.g., National Wildlife Refuges), or in habitat of threatened or endangered species known to be impacted by towers. Local meteorological conditions should be reviewed, and areas with an especially high incidence of fog, mist, and low cloud ceilings should be avoided, especially during spring and fall migrations.
3. If taller towers (more than 199 feet [61 m] AGL) requiring lighting to warn pilots must be constructed, the minimum amount of warning and obstruction lighting required by the FAA should be used. Where permissible by FAA and local zoning regulations, only white strobe lights should be used at night. These should be up-shielded to minimize disruption to local residents, and should be the minimum number, with minimum intensity and number of flashes per minute (i.e., the longest duration between flashes, currently three seconds) allowed by the FAA. The use of solid red or pulsating red warning lights should be avoided at night. Construction techniques which do not require the use of guy wires should be employed whenever possible.
4. Guyed towers constructed in known raptor or waterbird concentration areas should use daytime visual markers (e.g., bird diverter devices) on the guy wires to prevent collisions by these diurnally active species. Suggested bird avoidance guidelines are available from the electric utility industry (APLIC 1994, 1996), and research and experimental design recommendations are available from the wind generation industry (NREL 1995, Anderson et al. 1999).
5. Towers should be constructed in a way that limits or minimizes habitat loss within the tower "footprint." Road access and fencing should be minimized to reduce or prevent habitat fragmentation and disturbance, and to reduce above-ground obstacles that might impact birds in flight. A larger tower footprint, however, is preferable to construction of a guy-supported tower.
6. If significant populations of breeding birds are known to occur within the proposed tower footprint, construction should be limited to those months when birds are not nesting (i.e., times other than spring and summer).
7. New towers should be designed structurally and electrically to accommodate the applicant's antenna(s), and comparable antennas for at least two additional users, to reduce the number of future towers -- unless this design would require the addition of lights or guy wires to an otherwise unlighted and/or unguyed tower.
8. Security lighting for on-ground facilities and equipment should be down-shielded to keep light within the boundaries of the site and minimize its potential attraction for birds.
9. If a tower is constructed or proposed for construction, FWS personnel and/or researchers from the Communication Tower Working Group or their designees should be allowed access to the site after construction is complete to conduct both large (e.g., crane [Gruidae], swan, and goose [Anatidae]) and small dead-bird searches; to place net catchments below the tower but above the ground; to position radar, Global Positioning System, infrared, thermal imagery, and acoustical monitoring equipment as necessary to assess and verify bird migrations and habitat use; and to gain information on the impacts of various tower sizes, configurations, and lighting regimes.
10. If constructing multiple towers, providers should consider the cumulative impacts of all of those towers on migratory birds, including impacts on birds listed as threatened and endangered and nongame species of management concern. The impacts of each individual tower should also be considered.
11. If significant numbers of breeding, feeding, or roosting birds are known to habitually use a proposed tower construction site, relocation to an alternate site is recommended. If this is not an option, seasonal restrictions on construction may be advisable in order to avoid disturbance during periods of high bird activity.
12. Towers no longer in use or determined to be obsolete should be removed within 12 months of the cessation of use.
The Communication Tower Working Group (CTWG) was created at the June 29, 1999, meeting of RESOLVE, then consisting of 15 members. The task of the Working Group is to develop and implement a nationwide research protocol intended to determine what causes birds to collide with towers, and what can be done to avoid these collisions. The Working Group held its first meeting on November 2, 1999, with representatives from 7 Federal and 2 state agencies, 9 research organizations and universities, 8 industry representatives, and 6 non-governmental organizations (NGOs). The meeting was chaired by DMBM (A. Manville). Subcommittees were created to deal with research, funding and partnerships, and legal issues. All three subcommittees have met and subcommittee chairs reported back to the full Working Group on June 16, 2000.
The Research Subcommittee has been tasked specifically to address the following issues through the development and implementation of a research protocol. Thirty stakeholders attended an all-day meeting of the Subcommittee on April 17, 2000, approving a draft nationwide research protocol. The protocol calls for the following research:
1. The protocol should quantify, with statistical certainty, the cause(s) and effects of lighting color, lighting duration, and the correlation between bird kills and weather.
2. Research should attempt to determine critical tower height and if there is a height threshold above which bird kills increase significantly.
3. Research should attempt to assess and quantify the most dangerous situations for birds.
4. The protocol should assess radar, acoustic, and ground survey techniques that could be used to determine major migratory corridors or routes (not necessarily flyway-oriented) to avoid siting towers in these areas.
5. The initiative must develop an effective dead-bird monitoring protocol, which will borrow heavily from the wind generation (Anderson et al. 1999) and power line industries (APLIC 1994, 1996).
6. The protocol should attempt to assess the cumulative impacts of all towers on bird populations in North America. For example, in 1979, Dick Banks published a special scientific report for the Service (Banks 1979) estimating annual bird mortality from tower strikes. Based on 50% of the 1,010 television transmitting towers then existing in the United States, Banks estimated annual mortality at nearly 1.3 million birds. He made no accounting for radio transmitting towers and airport ceilometers, or for the other half of the existing television towers. Today -- based on Banks' estimate, models from the Tall Timbers Research Station, extrapolations from Bill Evans and others, and the current known number of lit towers -- the Service estimates annual mortality at 4-5 million birds. This is a conservative estimate and could conceivably be off by an order of magnitude. Only systematic monitoring will provide us a better estimate.
A systematic research study may take 3-5 years to complete, with further testing, ground-truthing, and verification of mitigation measures that are anticipated to be discovered. Following approval of the detailed draft nationwide research protocol in April 2000, 36 attending members of the Communication Tower Working Group on June 16, 2000, approved the framework for the nationwide research initiative. Specifically, Southwestern Bell Wireless, Inc., solicited mini-research proposals from the Research Subcommittee for possible funding, of which some of the pilot studies could begin as early as Fall 2000. The pilot studies will likely compare lighting, assess radars, refine dead bird searches, develop a Geographic Information System study plot, assess the most dangerous towers, examine birds' retinal photoreceptors, and test bird behavioral responses to light. Applicable findings discovered during pilot study investigations will be applied to the nationwide monitoring effort.
To initiate a nationwide bird-strike monitoring study that could begin as early as Fall 2001, and to assess the cumulative impacts of towers on migratory birds, the Cellular Telecommunications Industry Association (CTIA) also solicited a detailed, fully budgeted research proposal from the Working Group at the June 16th meeting. The 3-5 year monitoring effort could cost in excess of $15 million. At this writing, the Research Subcommittee is beginning work on this proposal for CTIA.
Once the research is completed and the results analyzed, recommendations will be presented both to the FCC and to industry. During the research effort, where pertinent, statistically significant findings are discovered, that information and possible recommendations will be provided to the industry as quickly as possible.
To develop and implement the research, the Service will work in partnership with the communication industry, other government agencies, the research community, NGOs, and the public to solve this problem. We will work in partnership with the communication industry to voluntarily solve bird-kill problems at communication towers, rather than solving the problem through regulatory or enforcement means. To date, two partnerships have worked well and we will use these as models for future work with the communication industry. In 1972, for example, representatives from the electric utility industry, Federal agencies (including the FWS), and NGOs first met to address the problem of bird collisions and electrocutions at electric power lines. In 1988, the Avian Power Line Interaction Committee (APLIC) was officially created, the Service a founding member with several electric utilities. In 1975, the first edition of Suggested Practices for Raptor Protection was published, with an update of Mitigating Bird Collisions with Power Lines (APLIC 1994) more recently published. The electrocution avoidance document, Suggested Practices for Raptor Protection on Power Lines (APLIC 1996) was just reprinted in the Spring 2000. These publications speak to voluntary suggested practices to avoid bird collisions and electrocutions; the guidance in these publications is voluntary.
In like fashion, the Avian Subcommittee of the National Wind Coordinating Committee was created in 1994, with the Service again a founding member. This partnership is in an embryonic stage compared to APLIC, with the wind generation industry recently publishing a guidance document for conducting research on avian/wind interactions (Anderson et al. 1999). Following necessary research, the intent also is to develop voluntary suggested practices for wind generators, similar to what has been done for power lines.
To review and assess the current literature, research, and methodologies for studying communication towers, independent consultant Paul Kerlinger was contracted by DMBM to conduct a review dating back to 1995. The review analyzed work in the United States, Canada, Europe, Australia, and New Zealand. The document is publicly available on the Service's new web site, http://migratorybirds.fws.gov/issues/towers/review.pdf.
The issue before us today is unprecedented. The research about to be jointly conducted provides an opportunity to determine what about a man-made structure attracts and not infrequently kills migratory songbirds, and hopefully what we can do to reduce or ideally eliminate the problem. Research discoveries may also be applicable to other construction, including tall buildings, smokestacks, tall monuments, wind turbine generators, utility towers, and other tall structures. Research learned about bird behavior and movements will likely fill many gaps in our current information database. We'll better be able to determine the status of some bird populations and determine the cumulative impacts of communication towers on migratory songbirds. The benefits of the collaborative approach between industry, academia, agencies, and the conservation community are many. Most importantly, this can be a win:win situation for all parties and the resources concerned.
Anderson, R., M. Morrison, K. Sinclair, D. Strickland, H. Davis, and W. Kendall. 1999. Studying wind energy/bird interactions: A guidance document. In Metrics and Methods for Determining or Monitoring Potential Impacts on Birds at Existing and Proposed Wind Energy Sites. Avian Subcommittee, National Wind Coordinating Committee. 87 pp.
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