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re: Wind Power and birds (long)

Hi Carolinabirders,

I opened up that fact sheet that Linda was having trouble with and pasted 
it into an e-mail. The numbers in brackets [1] refer to the list of 
references at the end. It's an interesting conflict, and not an easy one 
to resolve: do we place priority on protecting Condors, which have 
already gone extinct in the wild once and only returned through a 
multimillion dollar effort by the US government? Or do we risk the 
condor's future for the sake of much larger numbers and diversity of 
other birds and even more of non-avian organisms which are not endangered 
yet (mostly), but certainly could be soon if we continue using fossil 
fuels as our primary energy source? Maybe this whole thing is wind-power 
industry propaganda, but they certainly seem to be working a lot harder 
to make their facilities bird-friendly than any oil company ever has. 
Read and enjoy...



From the American Wind Energy Association

The impact of wind energy development on bird populations has become an 
issue because of bird deaths in California's Altamont Pass, one of the 
world's largest wind development areas. Altamont Pass, located east of 
San Francisco, is an area with high raptor activity year-round and a high 
population of ground squirrels and other rodents that furnishes an 
abundant prey base for raptors.

Birds collide with numerous other obstacles, both natural and of human 
manufacture, that are located along their flight paths. Some of these 
collisions are attributed to visual problems such as reflections from 
glass windows or the shrouding of stationary structures by fog. Raptors 
in pursuit of prey have crashed into buildings and natural obstructions 
such as trees. Some believe raptors fly into wind turbines under similar 
conditions of "target fixation" during "hot pursuit."

Q: How widespread is avian mortality associated with wind projects?
A: To date, large-scale wind development within the U.S. has only taken 
place at a few areas. However, there is evidence that this is a 
site-specific problem which does not affect wind turbines generally. 
Limited studies at other wind sites in California and Minnesota where 
raptor activity is low have found few or no kills. The California Energy 
Commission is currently planning detailed studies of that state's two 
other major wind development areas Tehachapi Pass near Bakersfield and 
San Gorgonio Pass near Palm Springs to develop data that can be compared 
with Altamont Pass.

Q: How many birds collide with wind turbines?
A: Only a few studies have examined the frequency of bird collisions for 
significant numbers of wind turbines  one in Denmark and two in 
California. These indicate that a bird will collide with a given wind 
machine no more than approximately once every 8 to 15 years [1]. Higher 
levels of mortality have been found by some studies of smaller numbers of 
turbines in coastal locations with large concentrations of waterfowl [2], 
and it seems appropriate to use greater caution in siting wind projects 
in such areas or in known areas of high migration [3].

In the Altamont Pass Wind Resource Area (which has some 7,000 wind 
turbines), a two-year study found 182 dead birds, of which 119 were 
raptors. The study attributed 55 percent of raptor deaths to collisions 
with turbines, eight percent to electrocutions from power lines, 11 
percent to collisions with wires, and 26 percent to unknown causes [4]. 

Q: How many birds die in collisions with other human structures?
A: It is estimated that each year, 57 million birds die in collisions 
with vehicles; 1.25 million in collisions with tall structures (towers, 
stacks, buildings); and more than 97.5 million in collisions with plate 
glass [5]. 

Q: What are the effects of other energy sources on birds?
A: In a single oil shipping accident, the Exxon Valdez oil spill in 
Alaska's Prince William Sound, more than 500,000 migratory birds 
perished  or about 1,000 times the estimated annual total in California's 
wind power plants [6]. And a study at a single Florida coal-fired power 
plant with four smokestacks recorded an estimated 3,000 deaths in a 
single evening during a fall migration [7]. 

Although the larger effects of fossil fuels, such as air pollution, acid 
rain, and global climate change, are difficult to measure with 
precision, they are much more far-reaching than those of wind energy. 
Here is what the environmental group Public Citizen had to say on the 
subject in a 1989 statement supporting a proposed wind power plant: 
" . . . U.S. reliance on coal, oil, and nuclear power is posing grave 
threats to society: acid rain, urban smog, radioactive waste, and global 
warming. Sulfur emissions from coal have damaged or destroyed whole life 
systems in hundreds of lakes and streams and thousands of acres of 
forests. "Global warming threatens many species which may be unable to 
survive even a gradual change in climate  a virtual certainty unless 
reliance on fossil fuels is greatly reduced within the next decade. In 
the worst case, whole ecosystems may disappear as a result of rising 
tides and shifting weather patterns [8]."

While no numbers are available on the number of birds killed by 
collisions with nuclear power plant cooling towers, scientists have 
documented severe effects on marine habitats from the discharge of heated 
water from nuclear facilities. In one widely-publicized study reported in 
1989, for example, a neutral committee of three biologists found that a 
single nuclear power plant, the San Onofre Nuclear Generating Station in 
California, killed some 21 tons of fish each year, including "several 
billion" fish larvae [9].

Q: Do wind turbines affect birds in other ways?
A: Yes. Both positive and negative impacts of wind energy development on 
birds have been identified. Positive impacts include retaining natural 
habitat and providing birds with an environment safe from human 
harassment. Negative impacts include loss of habitat, electrocution, and 
collisions with associated equipment such as wind measurement towers 

Q: Can anything be done to reduce the impact of wind generating 
facilities on birds?
A: In large wind power plant development areas, the general strategy is 
to try to make the plant safer for the birds. In smaller project areas, 
it may be more practical to try to keep the birds out of the facility by 
employing warning techniques. Other measures include: Several avian 
experts have suggested that raptor activity around wind turbines can be 
reduced by taking measures to reduce the number of perches available to 
birds on the turbine and tower. Many turbines in Altamont Pass, for 
example, have steel "lattice" towers with flat crossbars that are ideal 
for perching. It is clear that the tubular tower greatly reduces 
opportunities for perching and is rapidly becoming the structure of 
choice for new wind energy projects.

Wind turbine manufacturers have reduced the amount of noise produced by 
their machines [11]. Although this is being done primarily to avoid 
disturbing residents of areas surrounding windfarms, it is likely to also 
reduce the disturbance to nesting birds.

European studies suggest that the configuration of windfarms and 
placement of turbines can be carried out in such a way as to reduce bird 
collisions [12]. For example, if a wind plant is sited in an area of 
heavy bird migration, turbines can be spaced more widely as seen from the 
direction of migration. This is still an area which needs much more 
study. The more that is known about the "micrometeorology" of a site (how 
the wind flows across the area to be developed) and how birds use the 
area, the easier it will be to reduce the level of risk for birds in a 
wind facility.

One wind company has tested a blade painting pattern that will provide a 
high level of contrast between turbine blades and the general background 
in a variety of lighting conditions. The Electric Power Research 
Institute has reported that experiments indicate that it may be possible 
to use broadcasts of a certain radio frequency to discourage birds from 
entering areas such as wind plants or airports where there is a risk of 
collision. A variety of other innovative approaches are possible. 
However, because of the relatively small number of birds that die in 
collisions with any given turbine or group of turbines, it may take an 
extended period of time to determine whether a given technique is 
successful or not.

Q: What else is the wind industry doing to address this problem?
A: The wind industry is committed to taking the necessary measures to 
reduce avian mortality. Leading companies in the U.S. wind energy 
industry, in conjunction with AWEA, have established an Environmental 
Task Force to coordinate industry research, education, and mitigation 
efforts. The task force lobbied successfully to have $2 million of the 
federal Department of Energy's wind energy research funds set aside for 
avian research projects, and has worked with DOE and National Renewable 
Energy Laboratory staff and environmental groups to develop research 
priorities. AWEA is also collaborating with other groups in Minnesota to 
establish a baseline avian population assessment in wind development 
areas. Current research activities include work to develop a method of 
scientifically measuring the risk to birds presented by a given wind 
plant, to determine the raptor vision acuity, and to find out how bird 
populations are affected by wind plant kills.

The National Wind Coordinating Committee (NWCC), a multi-stakeholder 
group formed in 1993 to "ensure the responsible use of wind power in the 
United States," has established a Subcommittee on Avian Issues that 
includes representatives from the U.S. Fish and Wildlife Service and the 
National Audubon Society. The Subcommittee has coordinated the work of 
several leading experts on wind/avian interactions to develop standard 
terms and formulas ("metrics") to describe the extent to which birds use 
a given area of land and the risk that they face from human construction 
(whether wind plants, freeways, buildings, or other structures) on that 
land. Following the subcommittee's work on metrics, AWEA members are 
helping to fund a major effort by the California Energy Commission to 
examine avian mortality in San Gorgonio Pass and Tehachapi Pass. The 
Commission study is using the metrics to evaluate bird risk in these wind 
development areas. AWEA member companies have committed to contribute 
$50,000 toward the cost of this work, have opened their facilities to the 
studies, and have assisted Commission staff in carrying out the studies. 
Early research indicated that lattice towers that permit perching might 
contribute to bird kills, and as a result, industry is largely using 
tubular towers in new installations.

AWEA's Environmental Task Force commissioned ornithologist Edward Colson 
to prepare a summary of literature on avian effects of windpower. 
Colson's report, "Avian Interactions with Wind Energy Facilities: A 
Summary," is now available from AWEA. Kenetech Windpower established an 
Avian Research Task Force that included several noted ornithologists. The 
Kenetech Task Force initiated a series of studies to attempt to determine 
what birds see and hear, and what mitigation measures might be effective. 
Those studies were carried out at Kenetech's Altamont Pass facilities and 
at Boise State University in Idaho, and their results have been compiled 
for publication.

Avian mortality is an issue that demands, and is receiving, continuing 
attention and mitigation efforts from the wind industry, government and 
the environmental community.

[1] "Impact of Wind Turbines on Birdlife: An Overview of Existing Data 
and Lacks in Knowledge in Order of the European Community," Benner, J. H. 
B., et al, Concept (Draft) Final Report, July, 1992, pp. 22-23. 
Consultants on Energy & the Environment (CEA), Rotterdam, The Netherlands.

[2] "Impact of Wind Turbines on Birdlife," note 1, supra.

[3] This is intended only as a general caution. At many locations within 
known migratory routes, migrating birds fly at levels well above wind 
turbine rotor heights and are not threatened by wind project development.

[4]"Wind Turbine Effects on Avian Activity, Habitat Use, and Mortality in 
Altamont Pass and Solano County Wind Resource Areas, 1989-1991," Orloff, 
S., and Flannery, A., 1992, Executive Summary, p. x. Biosystems Analysis, 
Inc., Sacramento, Calif., 1992.

[5] "Kenetech Windpower Avian Research Program Update," 1994, p. 3. 
Kenetech Windpower, Washington, D.C.

[6] Conversation with Donald Aitken, Union of Concerned Scientists, 
February 2, 1995.

[7] "Bird Casualties at a Central Florida Power Plant," Maehr, D. S., et 
al., Florida Field Naturalist, 11:45-49, 1983. Florida Ornithological 

[8] "Public Citizen Endorses Gorman Windfarm," note 8, supra.

[9] "Committee Finds Massive Sea Life Kills from San Onofre," 
Groundswell, Vol. 11, No. 2&3, Autumn, 1989. Nuclear Information and 
Resource Service, Washington, D.C.

[10] "Avian Interactions with Wind Energy Facilities: A Summary," Colson 
& Associates, January, 1995, Executive Summary, p. ii. American Wind 
Energy Association, Washington, D.C.

[11] "Comments, Questions and GMP's Responses Concerning Its Wind 
Development Ideas," September, 1992, p. 4. Green Mountain Power Co., 
South Burlington, Vt.

[12] "The Impact of the Experimental Windfarm at Oosterbierum on Birds," 
Winkelman, J. E., 1990. DLO Institute for Forestry and Nature Research, 
Arnhem, The Netherlands.

Joshua S. Rose
Duke University
Department of Zoology