Avian mortality at communications towers: background and overview. Albert M. Manville, II, Ph.D. Office of Migratory Bird Management
(MBMO), U.S. Fish and Wildlife Service, 4401 N. Fairfax Dr., Suite 634,
Arlington, VA 22203. Ph. 703/358- 1963. <Albert_Manville@fws.gov>.
Albert Manville, Workshop Co-chair, Introductory Remarks
Id like to welcome all of you to our first ever workshop on avian
mortality at communication towers. My name is Al Manville, Im with
the Office of Migratory Bird Management, U.S. Fish and Wildlife Service,
in Arlington, VA. Our other co-chair, my esteemed colleague is Bill Evans,
whom most of you know -- acoustical researcher, ornithologist, who has
been working on this issue for some time.
I would like to attempt to set the stage, and put the issue into context
of why we are here this afternoon, why this issue is of importance to all
of us. Migratory birds are a trust responsibility for the Fish and
Wildlife Service (FWS or Service). The Service is responsible for the
conservation and management of 836 species of migratory birds, 778 of
which are on so-called nongame species, while the remaining 58 are legally
hunted; all protected under Migratory Bird Treaty Act of 1918, as amended.
While populations of some of our bird species are doing well, in fact some
much too well as many of you are aware -- including Snow Geese, urban
Canada Geese, Cowbirds and Cormorants -- unfortunately, many others are
not. We are seeing continuing declines of over 200 species. Currently, we
have 75 species listed as Endangered and 15 species listed as Threatened
under the Endangered Species Act. We also currently have 124 species, so-
called nongame species of management concern, whose populations are
declining, in some cases precipitously. The next step for some of these
species could be listing under the Endangered Species Act. I imagine most
of you realize this is a train wreck we would prefer to avoid.
This current list of 124 nongame species has increased sizably for
various reasons from what was published in 1987, then 30 species of
management concern. For some one-third of the 836 species of birds, we
have essentially no population data, so what the impacts of the towers and
other mortality factors are on these birds we unfortunately don't really
now. Thus the individual factors that kill birds including collisions with
towers, electric power lines, wind generators, glass windows, cats,
aircraft, cars, electrocutions, poisoning from pesticides, oil spills, and
other causes are of growing concern to the FWS. What the impacts of towers
are to bird populations we simply don't know. That's one of the reasons
why we are here this afternoon. Add to this the impacts of the loss and/or
the degradation of habitat to the above list of bird threats, and the
overall problems of bird survivorship and population stability can be
critical ones. Birds are big business in North America, and I might point
out that we must not underestimate their importance. Some 65 million
Americans feed, photograph and watch birds and spend more than $21 billion
per year pursuing these activities. Birdwatching has become America's
fastest-growing hobby increasing 150 percent in the past decade. More
Americans today reportedly go on vacation to watch birds that to play
golf. 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 their
success. Take, for example, one pair of adult warblers that will remove
caterpillars from more than one million leaves in a two-to-three-week
period while feeding their nestlings. In the Pacific Northwest, 24 species
of neotropical migrants feed on western spruce budworms and Douglas-fir
tussock moths, two of the most destructive defoliating insects in that
region. Birds remove countless weed seeds including exotic species that
compete for food crop and forest production. Birds distribute seeds of
important forest, shrub and tree species whose survival would not exist
without bird-seed dispersal. The global reduction of pollinators,
including birds, raises alarm. Two-thirds of our flowering plants are
pollinated by birds, bats and insects producing a global economic benefit
estimated at $117 billion per year. In short, birds are extremely
important to us all.
While the FWS plays other roles in the review of tower permitting and
placement through the National Environment Policy Act and Section 7 of the
Endangered Species Act, as you'll hear from Robert Willis later this
afternoon on the second panel of speakers, the Office of Migratory Bird
Management became actively involved in a tower- kill issue early last
year. By now many of you are well aware of the large kill that occurred on
January 22, 1998, at three towers and a natural gas pumping facility in
western Kansas where up to an estimated 10,000 Lapland Longspurs and a few
other species were killed that one snowy, foggy, night. The issue of the
bird kill at that site was almost immediately brought to our offices
attention by the American Bird Conservancy, The Ornithological Council,
the National Audubon Society and other groups asking what the Office of
Migratory Bird Management was going to do about this problem. On April 6th
of last year, I was asked to brief the Policy Council of the American Bird
Conservancy on, among other things, the mortality from bird strikes at
communication towers. At that time, I provided a partial but not complete
literature review and list of abstracts put together by Migratory Bird
staff member John Trapp. Following that meeting, informal discussions
continued with representatives from the Federal Communications Commission
(FCC), the Services Division of Habitat Conservation, and the Office
of Migratory Bird Management. On November 17th of last year,
representatives from the Services field, regional, and Washington,
DC, offices met at Adam Kellys office at Geo-Marine in Panama City,
FL, to discuss, Migratory bird conservation and communication
towers: avoiding and minimizing conflicts. Many of you, I hope, have
had a chance to look at the detailed minutes of that meeting which were
disseminated to the public. In December, Robert Fisher, senior mediator
for the environmental dispute resolution group RESOLVE, met with several
of us to discuss next steps. The culmination of that discussion led to a
meeting on June 29th of this year with 42 stakeholders from the
scientific, agency, non-governmental, and industry perspectives, many of
whom are here this afternoon. The meeting focused on research needs. A
Communication Tower Working Group was formed consisting of 15 stakeholders
from the RESOLVE meeting. The groups task is to create a structure
to put into place what research needs were discussed at that June 29th
meeting. Those research needs are to be further discussed this afternoon
which is exactly what we intend to do. What we hope to learn today will
help in formulating a research protocol and further identifying research
needs.
At the RESOLVE meeting, I indicated the Services interest in
developing a partnership with the communication industry much like we
already have with the electric utility and wind generating industries. We
need to look to the electric utility industry through the Avian Power Line
Interaction Committee also of which the Service is a member, and to the
wind generation industry through the Avian Subcommittee of the National
Wind Coordinating Committee, also to which the Service is a member, to see
what these industries have done with similar bird collision and
electrocution problems, and perhaps look at their research protocols, and
their metrics and means documents, as a guidance and model of what we need
to do next. Paul Kerlinger will discuss, in part, this issue this
afternoon. I also had attempted at the RESOLVE meeting to reiterate that
the purpose of that meeting was not to lay blame. We have no intentions of
shutting down the communication industry nor do we intend to enlist our
sister agencies, the FCC, the Federal Aviation Administration, and the
Biological Resources Division of the U.S. Geological Survey, to conquer
new territory and combine forces to block industry growth. The focus of
this workshop, as was the focus of the RESOLVE meeting, is to review
known, anticipated, promising, and new research opportunities that will
result in minimizing or even avoiding bird collisions and mortalities.
Some have argued there is nothing we presently can do. I would disagree.
The Service currently recommends the following, especially for new towers:
1) If it all possible, co-locate. Put a planned tower on an existing tower
or on another structure. 2) Keep towers below 200 feet if it all possible.
The magic formula for lighting is anything taller than 199 feet above
ground level (AGL) is required by the FAA to be lit -- and we will hear
from David Bayley this afternoon from the FAA more about those
initiatives. 3) Keep towers unguyed if at all possible because the guy
wires are very problematic to the birds. 4) If it all possible, keep the
towers unlit. There are a number of towers less than 200 feet that are lit
and they may not necessarily need to be. Mike Allred will discuss this
issue in part this afternoon as well. However, there are still many
questions that we need to answer; let me throw out a few of these to you
this afternoon.
Question: how many birds are actually killed annually by towers? Dick
Banks authored a special FWS scientific report in 1979 projecting annual
mortality at upwards of 1.4 million birds per year based then on 1,100
existing tall towers. Today the FCCs February 1999 Antenna Structure
Registry Database places 48,642 lit towers greater than 199 feet AGL in
the United States, and this figure does not include towers classified as poles.
Some argue the figure could be closer to 80,000 lit towers. We do know
that more towers are planned, including the digitization of all television
stations by 2003 requiring an estimated 1,000 additional what I would
call, mega-towers (these are towers greater than 1,000 feet
AGL) that are going to be placed around the country.
Question: what are the true impacts of the existing and planned new
towers? Answer: We don't know. Based on Banks estimate, data from
Tall Timbers Research Station and other sources, Bill Evans conservatively
estimated current annual mortality at upwards of four million birds. The
figure could be off by an order of magnitude. Again, we simply don't know.
Perhaps a detailed research analysis might answer this question, but we
don't need reliable mortality data before we act. I must stress this
point. We already know that we have an important conservation problem and
we need to deal with it now. If I may borrow from an extrapolation that
Ron Larkin put together -- one of our speakers this afternoon -- if towers
presently are killing four million birds per year, that means that towers
are on average killing one bird every seven-and-a-half seconds, every day
and every night, all year long. These are mostly the little birds, the
songbirds. So this is, I would say, a fairly significant impact.
Question: what tower characteristics are least likely to cause migratory
bird collisions? In answer, probably towers less than 200 feet AGL,
unguyed, and unlit. Question: can we come up with relative risk categories
of tower characteristics that cause bird kills based on the best existing
information? Answer: we attempted to do that at Panama City, FL, last year
but there needs to be more work done on it. Question: are lights and light
colors the problem or is it the duration, the relative amount of dark vs.
light, during the blinking cycle of the light that makes a difference?
Answer: Michael Avery, Sid Gauthreaux, and Bob Beason have some important
suggestions that I hope they will share with us this afternoon on this
very issue. Question: what radar, acoustic and ground survey techniques
will be useful in determining major migratory bird movements and bird
migration timing? Answer: We will hear from Bill Evans, Adam Kelly and
others on this issue this afternoon as well. Question: can we develop an
effective monitoring protocol? Answer: Paul Kerlinger will address this
issue in part. Question: what is the scope of research already completed
or in progress? Answer:
Unfortunately, there isn't much. Question: what research needs to be
conducted? Answer: Ellen Paul presented a good framework for a research
study at our RESOLVE meeting. Michael Avery expanded on Ellen's
suggestions and this is what was suggested. We need a randomized selection
of tower study sites, stratified geographically, statistically rigorous,
of various tower height classes over a three-to-five-year period, spring
and fall, focused on lighting schemes including the use of radio telemetry
to determine bird movements towards lights to assess their responses and
develop preventative measures. Sounds like a very interesting suggestion
to say the least.
And question: what can we do with existing towers and new planned
towers? In answer, with existing towers there isn't too much, but if they
are currently lit with either solid red or blinking red lights, the white
flashing strobes seem to be of less hazard and impact to the birds so we
would recommend the lighting scheme to be changed. And with new planned
towers, there are a number of things we can look at. Siting is important.
Keeping the towers less than 200 feet, unguyed, and unlit, and if they are
over 199 feet, suggest using white strobe lights rather than the red
flashing incandescent lights. There are obviously many more questions
about the impacts of towers on birds than we have answers, but to answer
these many questions we all need to be working together. We also need to
do whatever we can now to minimize impacts, not necessarily wait until the
detailed research study is completed. To reiterate, what we can do is co-
locate, keep towers unguyed, unlit, and under 200 feet, and if they have
to be lit use the white lighting protocol.
So with those thoughts, let me pass the baton to our Co-chair, Bill
Evans, for his thoughts and observations this afternoon. Thank you.
Workshop Agenda
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