Of birds and blades: wind farms and our feathered friends
3/13/10 — Offshore wind turbines may be placed near Rhode Island without major harm to bird populations, according to the preliminary findings of a University of Rhode Island study. Last week, Peter Paton, chair of the URI Natural Resources Science Department, presented the first three months of ocean bird survey data at the Audubon Society of Rhode Island Environmental Education Center in Bristol.
Paton largely based his conclusions on the record of Danish wind farms which have been operating for 10 years. Studies indicate that birds, including a frequent visitor to Rhode Island, the common eider, adjust their migratory routes to avoid the turbines. “They fly as far as possible from wind turbines,” Paton said.
Little evidence exists that the Danish turbines kill birds from direct strikes. Of 235,000 bids observed, only 41 to 48 were hit by turbine blades, he says. More significant in Denmark, however, was documented displacement of the birds from their pre-wind turbine habitat, perhaps due to boat traffic to the energy project.
Eiders, scoters and other sea ducks forage for mussels and other food in water less than 25 meters deep, Paton noted, so locating turbines in Rhode Island waters that depth could force them to find food elsewhere. A small number of offshore wind farms would leave ducks with other places to feed, he theorized, but a large number of wind farms in shallow waters could dangerously reduce sea duck habitat.
Ideally, Paton says, turbines should be located away from areas with large numbers of birds, including the coast of Rhode Island and the seas immediately north, southwest and southeast of Block Island.
Alcids, a family of penguin-like birds that includes razorbills, common murre and dovekie are more likely to be affected by wind farm construction. The URI surveys indicate the birds, which feed on fish, are widely distributed in the seas near Rhode Island, so no matter where turbines are located, it will be alcid habitat.
Paton is overseeing the bird data collection as part of the Rhode Island Coastal Resource Management Council’s Ocean Special Area Management Plan (SAMP). The SAMP is a landmark ocean zoning plan designed to measure sea activities from commercial fishing to whale migratory routes and recommend specific uses for specific areas. The SAMP will cover the 1,500 square mile area within 30 miles of the Rhode Island coast, but not Narragansett Bay
The study has 11 land-based stations for bird counts, although none are on Block Island, and eight survey sites from boats. In addition, the entire SAMP area is regularly surveyed by plane. A special coastal survey is also underway for roseate terns, an endangered species. Sightings have been few, Paton noted, because the terns are not known to nest in Rhode Island. In addition, a portable radar station, lent by Audubon’s New Jersey branch, records birds from the north end of Block Island. Deepwater Wind operates another radar unit on Lewis Farm on the southwest corner of Block Island, to observe birds and bats, but it is not part of Paton’s survey.
While he hopes the SAMP bird report, scheduled for completion by June 2010, will minimize turbine impact on birds off the Rhode Island coast, Paton expressed more concern for the Cape Wind turbine project proposed for Nantucket Shoals, south of Cape Cod. “Very few places in the world can you find such concentrations of sea ducks,” said Paton, who estimated Nantucket Shoals has at least 10 times as many birds as the Rhode Island SAMP area.
Paton noted that wind turbines’ reputation as “Cuisinarts of the sky” that kill large numbers of birds, originates from a 5,000 turbine project in Altamont Pass, Calif. The Altamont turbines kills 7,000 to 9,000 birds a year, according to Audubon, including an estimated 500 raptors. Audubon has a pending law suit against the project for failing to consider its impacts on birds. Experts agree the turbines were poorly placed when built in the 1980s.
Offshore turbines, however, are larger and taller than the Altamont Pass turbines, Paton said, and less of a direct threat to birds. The “vast majority” of sea ducks typically fly less than 10 meters above the water, he noted, while the turbine blades would be 25 meters above the sea. In addition, migrating songbirds, according to radar studies, typically fly at altitudes above the tops of turbines.
According to a 2005 U.S. Forest Service estimate, humans cause approximately one billion bird deaths a year, but only 28,500 are attributed to wind turbines. The biggest killers are buildings (550 million), power lines (130 million), cats (100 million), cars (80 million) and pesticides (67 million).