Bird and Bat Mortality

Bird near Big Horn Wind Farm, Wyoming. Image: NREL Image Library
Bird near Big Horn Wind Farm, Wyoming.
[Image: NREL Image Library]

Wind energy has many benefits as a clean, renewable energy source, but it is also associated with several environmental impacts. One of these impacts is bird and bat mortality from wind turbine collisions, especially a concern in areas with sensitive bird and bat species and high collision rates.

The total estimated annual avian collision mortality rate from wind turbines is low (0.01 - 0.02 %) when compared with fatality rates due to collisions with communication towers (1 - 2%) and with vehicles (15 - 30%) (Erickson et al., 2001 [PDF])]. However, these collisions are still a cause of concern, and recommended Wind Turbine Guidelines for assessing and minimizing impacts to wildlife, including collisions, are now available.

Bat collisions with wind turbines are also a potential negative environmental impact of wind energy, and can be high in some site specific locations.

Many birds and bats serve important ecological roles as pollinators. As wind energy development continues to grow, more research, monitoring, and planning will be needed to determine the best methods to reduce bird and bat mortality from wind turbine collisions.

Birds and Power Lines

Recommended best practices and guidelines for minimizing bird mortality due to electrocution, collision, and nest removal at power lines are provided by the following resources:

Featured Bird Conservation Resource

Bird Conservation Node logo [Image: NBII]
[Image: NBII]

The NBII Bird Conservation Node provides electronic access to North American bird population and habitat data maintained by a broad coalition of federal, state, and non-governmental partners. These data resources are vital to the planning and evaluation of science-based bird conservation strategies.

Bird data and information useful in assessment and mitigation of renewable energy impacts on birds is available in the Maps & Data, Which birds do we conserve?, and How do we conserve birds? web pages.

Bird Conservation

Bald Eagles [Photo: John J. Mossesso, NBII LIFE]
Bald Eagles on Light Pole
[Photo: John J. Mossesso, NBII LIFE]

Birds provide aesthetic enjoyment, as well as important ecological services (seed dispersal, pollination, predation, scavenging, nutrient deposition, ecosystem engineering), economic services (food, recreation), and cultural services (art, religion). Conservation of birds and their habitats has been a national priority in the United States since the early 1900s, when scientific evidence showed that human activities could negatively impact the long-term sustainability of bird populations. Energy production and associated infrastructure, including energy transmission and distribution lines, may have negative impacts on some species of birds in the absence of safety precautions. The following renewable energy types are known to have impacts on birds and their habitats:

Biofuel production can initially result in a change in land cover community or type, which may in turn change the bird species composition present. However, certain biofuel crops, when used within their native ranges, can provide quality nesting cover for grassland birds.

Geothermal energy development can result in habitat fragmentation from infrastructure building.

Solar energy development can result in habitat fragmentation, and birds that fly into a concentrated beam of sunlight produced by solar energy technology can be injured or perish.

Wind energy development can result in habitat fragmentation, and electrocution or collisions with turbines can occur, resulting in bird injury or mortality.


Resources on Birds and Wind Energy
Showing 10 of 27 ( Show All )
Resources on Birds and Biofuels
Showing 7 Results
CollapseAn Analysis of the Environmental Impacts of Energy Crops in the USA: Methodologies, Conclusions and Recommendations
Description: Various national and regional groups of bioenergy stakeholders have issued consensus recommendations and guidelines for sustainable bioenergy development. As reported in this article, it is a consistent conclusion from these efforts that displacing annual agricultural crops with native perennial biomass crops would very likely help restore natural ecosystem functions in worked landscapes, and help to preserve natural biodiversity. Conversely, if biomass crops displace more natural land cover -- such as forests and wetlands -- there would very likely be a loss of ecosystem functions and reduced biodiversity.
Resource Type: Unpublished Documents
Resource Format: URL
Publisher: National Audubon Society
ExpandAvian Response to Harvesting Switchgrass for Biomass in Southern Iowa
ExpandBird habitat benefits of using switchgrass for biomass fuel in the U.S. Midwest
ExpandBird habitat benefits of using switchgrass for biomass fuel in the U.S. Midwest
ExpandBirds are Chirping Over Cellulosic Biofuels
ExpandGrassland bird response to harvesting switchgrass as a biomass energy crop
ExpandPotential effects on grassland birds of converting marginal cropland to switchgrass biomass production
Resources on Birds and Geothermal Energy
Showing 2 Results
CollapseEnvironmental Impacts of Renewable Energy Technologies
Description: This webpage has an overview of the environmental impacts of renewable energy technologies including wind energy, solar energy, geothermal energy, hydropower, and biomass power. It also discusses air pollution, greenhouse gases, implications for agriculture and forestry.
Resource Type: Issue Overviews
Resource Format: URL
Publisher: Union of Concerned Scientists
ExpandIt's Man vs. Bird in a Quest for Power
Resources on Birds and Solar Energy
Showing 3 Results
CollapseEnvironmental Impacts of Renewable Energy Technologies
Description: This webpage has an overview of the environmental impacts of renewable energy technologies including wind energy, solar energy, geothermal energy, hydropower, and biomass power. It also discusses air pollution, greenhouse gases, implications for agriculture and forestry.
Resource Type: Issue Overviews
Resource Format: URL
Publisher: Union of Concerned Scientists
ExpandIt's Man vs. Bird in a Quest for Power
ExpandSolar Energy and the Environment

Raptor Mortality at Altamont Pass

Altamont Pass Wind Resource Area [Photo: California Energy Commission]
Altamont Pass Wind Resource Area [Photo: California Energy Commission]

The Altamont Pass Wind Resource Area (APWRA) in Northern California was established in 1982 and contains over 5,000 wind turbines that provide 1.1 billion kilowatt-hours of electricity annually. The APWRA is a well-known wind farm, because it has high numbers and rates of raptor kills, including many federally protected species. The APWRA is responsible for the deaths of hundreds of birds of prey each year, including golden eagles, red-tailed hawks, owls, vultures, kestrels, and falcons.

The high levels of raptor mortality at Altamont Pass can be attributed to unfavorable interactions between wind turbine configuration and raptor habitat utilization in the area. Analysis has identified possible measures that may mitigate bird mortality at this wind farm and elsewhere, including replacing older wind turbines with more carefully placed, modern equipment.


Sources:

Species Spotlight

Greater sage grouse [Photo: U.S. Fish and Wildlife Service]
Greater sage grouse
[Photo: U.S. Fish and Wildlife Service]

Greater Sage Grouse
Centrocercus urophasianus

Description: The greater sage grouse is a large bird that can grow up to 30 inches long and two feet tall, and can weigh up to seven pounds. This is a ground-dwelling, round-winged bird that has legs feathered to the base of its toes, and has a long pointed tail. Males have white necks and air sacks on their breasts that they inflate to attract females, who are usually smaller in size.

Life History: Males puff up their air sacs for display on breeding grounds known as "leks". Females visit these leks to mate, and then raise the young without help from the males, who play no role in raising the young. The same leks are often used for many years. Although many males may display at a lek, only one or two males are picked by the females for mating.

Habitat: Are found in sagebrush habitat at elevations between 4,000 and 9,000 feet. Feed exclusively on sagebrush during the winter.

Distribution: Found in many western U.S. states including Washington, Oregon, Idaho, Utah, Nevada, Colorado, South Dakota, North Dakota, Montana, California, and in parts of Canada including Alberta and Saskatchewan.

Status: The traditional breeding grounds, or leks, are vital to the reproductive success of the greater sage grouse. Currently, these leks are being threatened as a result of nonrenewable and renewable energy development as well as grazing, invasive species, and wildfires. It has been found that the grouse will avoid their leks if there is a disturbance such as a road or well within a few miles. Also, oil and gas development has historically led to die-offs of the grouse. As of March 2010, the species is currently not listed as endangered, but is on a list of candidate species that is reviewed annually.

Resources: U.S. Fish and Wildlife Service
Cornell Lab of Ornithology
Las Vegas Sun News

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