U.S. Fish and Wildlife Service logo
United States Department of the Interior

Washington, D.C. 20240

September 14, 2000
To: Regional Directors 
From: Director            /s/ Jamie Rappaport Clark
Subject: Service Guidance on the Siting, Construction, Operation and Decommissioning of Communications Towers

Construction of communications towers (including radio, television, cellular, and microwave) in the
United States has been growing at an exponential rate, increasing at an estimated 6 percent to
8 percent annually. According to the Federal Communication Commission’s 2000 Antenna
Structure Registry, the number of lighted towers greater than 199 feet above ground level (AGL)
currently number over 45,000 and the total number of towers over 74,000. Non-compliance
with the registry program is estimated at 24 percent to 38 percent, bringing the total to 92,000
to 102,000. By 2003, all television stations must be digital, adding potentially 1,000 new
towers exceeding 1,000 feet AGL.

The construction of new towers creates a potentially significant impact on migratory birds,
especially some 350 species of night-migrating birds. Communications towers are estimated
to kill 4-5 million birds per year, which violates the spirit and the intent of the Migratory Bird
Treaty Act and the Code of Federal Regulations at Part 50 designed to implement the MBTA.
Some of the species affected are also protected under the Endangered Species Act and Bald
and Golden Eagle Act.

Service personnel may become involved in the review of proposed tower sitings and/or in the
evaluation of tower impacts on migratory birds through National Environmental Policy Act
review; specifically, Sections 1501.6, opportunity to be a cooperating agency, and 1503.4,
duty to comment on federally-licensed activities for agencies with jurisdiction by law, in this
case the MBTA, or because of special expertise. Also, the National Wildlife Refuge System
Improvement Act requires that any activity on Refuge lands be determined as compatible with
the Refuge system mission and the Refuge purpose(s). In addition, the Service is required by
the ESA to assist other Federal agencies in ensuring that any action they authorize, implement,
or fund will not jeopardize the continued existence of any Federally endangered or
threatened species.

A Communication Tower Working Group composed of government agencies, industry,
academic researchers and NGO’s has been formed to develop and implement a research
protocol to determine the best ways to construct and operate towers to prevent bird strikes.
Until the research study is completed, or until research efforts uncover significant new
mitigation measures, all Service personnel involved in the review of proposed tower sitings
and/or the evaluation of the impacts of towers on migratory birds should use the attached
interim guidelines when making recommendations to all companies, license applicants,
or licensees proposing new tower sitings. These guidelines were developed by Service
personnel from research conducted in several eastern, midwestern, and southern states,
and have been refined through Regional review. They are based on the best information
available at this time, and are the most prudent and effective measures for avoiding bird
strikes at towers. We believe that they will provide significant protection for migratory
birds pending completion of the Working Group’s recommendations. As new information
becomes available, the guidelines will be updated accordingly.

Implementation of these guidelines by the communications industry is voluntary, and our
recommendations must be balanced with Federal Aviation Administration requirements
and local community concerns where necessary. Field offices have discretion in the use
of these guidelines on a case by case basis, and may also have additional recommendations
to add which are specific to their geographic area.

Also attached is a Tower Site Evaluation Form which may prove useful in evaluating
proposed towers and in streamlining the evaluation process. Copies may be provided
to consultants or tower companies who regularly submit requests for consultation, as
well as to those who submit individual requests that do not contain sufficient information
to allow adequate evaluation. This form is for discretionary use, and may be modified
as necessary.

The Migratory Bird Treaty Act (16 U.S.C. 703-712) prohibits the taking, killing,
possession, transportation, and importation of migratory birds, their eggs, parts, and
nests, except when specifically authorized by the Department of the Interior. While
the Act has no provision for allowing unauthorized take, it must be recognized that
some birds may be killed at structures such as communications towers even if all reasonable
measures to avoid it are implemented. The Service’s Division of Law Enforcement carries
out its mission to protect migratory birds not only through investigations and enforcement,
but also through fostering relationships with individuals and industries that proactively seek
to eliminate their impacts on migratory birds. While it is not possible under the Act to
absolve individuals or companies from liability if they follow these recommended guidelines,
the Division of Law Enforcement and Department of Justice have used enforcement and
prosecutorial discretion in the past regarding individuals or companies who have made
good faith efforts to avoid the take of migratory birds.

Please ensure that all field personnel involved in review of FCC licensed communications
tower proposals receive copies of this memorandum. Questions regarding this issue
should be directed to Dr. Benjamin Tuggle, Chief, Division of Habitat Conservation,
at (703)358-2161, or Jon Andrew, Chief, Division of Migratory Bird Management,
at (703)358-1714. These guidelines will be incorporated in a Director’s Order and
placed in the Fish and Wildlife Service Manual at a future date.

Service Interim Guidelines For Recommendations On
Communications Tower Siting, Construction, Operation, and Decommissioning

Any company/applicant/licensee proposing to construct a new communications tower
should be strongly encouraged to collocate the communications equipment on an existing
communication tower or other structure (e.g., billboard, water tower, or building mount).
Depending on tower load factors, from 6 to 10 providers may collocate on an existing tower.

If collocation is not feasible and a new tower or towers are to be constructed,
communications service providers should be strongly encouraged to construct towers
no more than 199 feet above ground level (AGL), using construction techniques which
do not require guy wires (e.g., use a lattice structure, monopole, etc.). Such towers
should be unlighted if Federal Aviation Administration regulations permit.

If constructing multiple towers, providers should consider the cumulative impacts of all
of those towers to migratory birds and threatened and endangered species as well as
the impacts of each individual tower.

If at all possible, new towers should be sited within existing “antenna farms” (clusters of towers).
Towers should not be sited in or near wetlands, other known bird concentration areas (e.g.,
state or Federal refuges, staging areas, rookeries), in known migratory or daily movement
flyways, or in habitat of threatened or endangered species. Towers should not be sited in
areas with a high incidence of fog, mist, and low ceilings.

If taller (>199 feet AGL) towers requiring lights for aviation safety must be constructed,
the minimum amount of pilot warning and obstruction avoidance lighting required by the
FAA should be used. Unless otherwise required by the FAA, only white (preferable) or
red strobe lights should be used at night, and these should be the minimum number,
minimum intensity, and minimum number of flashes per minute (longest duration between
flashes) allowable by the FAA. The use of solid red or pulsating red warning lights at night
should be avoided. Current research indicates that solid or pulsating (beacon) red lights
attract night-migrating birds at a much higher rate than white strobe lights. Red strobe
lights have not yet been studied.

Tower designs using guy wires for support which are proposed to be located in known
raptor or waterbird concentration areas or daily movement routes, or in major diurnal
migratory bird movement routes or stopover sites, should have daytime visual markers
on the wires to prevent collisions by these diurnally moving species. (For guidance on
markers, see Avian Power Line Interaction Committee (APLIC). 1994. Mitigating Bird
Collisions with Power Lines: The State of the Art in 1994. Edison Electric Institute,
Washington, D.C., 78 pp, and Avian Power Line Interaction Committee (APLIC). 1996.
Suggested Practices for Raptor Protection on Power Lines. Edison Electric Institute/Raptor
Research Foundation, Washington, D.C., 128 pp. Copies can be obtained via the Internet at http://www.eei.org/resources/pubcat/enviro/, or by calling 1-800/334-5453).

Towers and appendant facilities should be sited, designed and constructed so as to
avoid or minimize habitat loss within and adjacent to the tower “footprint”. However,
a larger tower footprint is preferable to the use of guy wires in construction. Road
access and fencing should be minimized to reduce or prevent habitat fragmentation
and disturbance, and to reduce above ground obstacles to birds in flight.

If significant numbers of breeding, feeding, or roosting birds are known to habitually
use the proposed tower construction area, relocation to an alternate site should be
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.

In order to reduce the number of towers needed in the future, providers should be
encouraged to design new towers structurally and electrically to accommodate the
applicant/licensee’s antennas and comparable antennas for at least two additional
users (minimum of three users for each tower structure), unless this design would
require the addition of lights or guy wires to an otherwise unlighted and/or unguyed tower.

Security lighting for on-ground facilities and equipment should be down-shielded to
keep light within the boundaries of the site.

If a tower is constructed or proposed for construction, Service personnel or researchers
from the Communication Tower Working Group should be allowed access to the site
to evaluate bird use, conduct dead-bird searches, to place net catchments below the
towers but above the ground, and to place radar, Global Positioning System, infrared,
thermal imagery, and acoustical monitoring equipment as necessary to assess and verify
bird movements and to gain information on the impacts of various tower sizes,
configurations, and lighting systems.

Towers no longer in use or determined to be obsolete should be removed within
12 months of cessation of use.
In order to obtain information on the extent to which these guidelines are being implemented,
and to identify any recurring problems with their implementation which may necessitate
modifications, letters provided in response to requests for evaluation of proposed
towers should contain the following request:

“In order to obtain information on the usefulness of these guidelines in preventing bird
strikes, and to identify any recurring problems with their implementation which may
necessitate modifications, please advise us of the final location and specifications of
the proposed tower, and which of the measures recommended for the protection of
migratory birds were implemented. If any of the recommended measures can not be
implemented, please explain why they were not feasible.”

For additional information regarding this Web page, contact Krista Bibb, in the Division of Policy
and Directives Management, at Krista_Bibb@fws.gov 
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