United States Department of Interior
Washington, DC 20240
September 14, 2000
To: Regional Directors
From: Director /s/ Jamie
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 Commissions 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 NGOs 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 Groups 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 Services 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 Directors 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,
- 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
- 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
- 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/licensees 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
- 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
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.