The Noble Bliss Windpark (Project) consists of 67 wind turbines constructed in 2007 within an area of 5,350 acres located in Wyoming County, near the town of Eagle, New York. Each turbine had a nameplate capacity of 1.5 megawatts (MW) and the project had a total capacity of the 100MW. Each consisted of a tubular steel tower, a 77 meter (253- foot) diameter rotor; and a nacelle which houses the generator, transformer, and power train. Each tower has a base diameter of approximately 5.47 meters (18 feet). The tower is topped by the nacelle which connects with the rotor hub that consists of three composite blades. With a rotor blade oriented in the 12 o’clock position, each turbine has a maximum height of approximately 389 foot (118.5 meters). All components of the turbine are painted white. Approximately 31% (21 out of 67) of the nacelles are equipped with L-864 FAA aviation obstruction beacons (lights) consisting of flashing red, strobe like lights for night.
This complete 3-season fatality study (Spring-Summer-Fall) was conducted from April 21–November 14, 2008. The approved protocol does not include winter studies as these are precluded by heavy snowfall and limited site accessibility. Twenty-three of 67 (34.3%) turbines in the Project were searched at one-day (N = 8 turbines), three-day (N = 8), and seven-day (N = 7) intervals. We completed a total of 1,954 individual turbine searches, equivalent to about 29 rounds of searches at the 23 turbines.
The term “incident” is defined here as referring to either a fatality or injury of a bird or bat found within the wind project area and does not necessarily indicate that the cause of death or injury was wind turbine related. This term is not to be confused with the term “incidental find”, which refers to incidents found at times other than during standardized surveys and at sites outside the 23 searched towers.
A total of 20 avian incidents (carcasses) were recorded by searchers during standardized surveys, representing 14 identified species. The remains of six incidents could not be identified to species. Of the 14 species, there were two raptor fatalities (Red-tailed Hawk, Sharp-shinned Hawk), eight songbird species, and one game bird fatality (American Woodcock). Twelve out of 20 incidents (60%) involved songbirds of eight species. We could determine migrant status for 15 incidents, out of which 12 (80%) were night migrants. The greatest number of bird incidents occurred during August. A total of seven additional avian incidents were recorded while on site, but not during standardized surveys (incidental finds). Of these additional fatalities, there were two raptor species (Red-tailed Hawks), one songbird species (two Red-eyed Vireos), one game bird (one Ruffed Grouse) and two unidentified bird incidents.
Remains of 74 bats were found by searchers during standardized surveys (April 21, 2008 to November 14, 2008), representing six species. Little Brown Bats (39.2%) were most numerous, followed by Hoary Bat (32.4%), Silver-haired Bat (17.1%), Eastern Red Bat (8.1%), Eastern Pipistrelle Bat (1.4%) and Big Brown Bat (1.4%). The greatest number of bat incidents occurred during the fall migration period, with 57 (77.0%) bat carcasses found between August 1, 2008 and September 30, 2008. A total of 15 additional bat incidents were recorded on site, outside of the standardized surveys. Of these fatalities, there were five Little Brown Bats, two Eastern Red Bats, four Silver-Haired Bats, three Hoary Bats and one unidentified bat.
Bat carcasses (mean = 22.9m) were found closer to turbine tower bases than bird carcasses (mean = 33.1m). There was moderate evidence to suggest that bat fatalities were greater at turbines close to wetland areas than at turbines located farther from wetlands. There was no evidence that bat or bird fatalities were greater at wooded vs. non-wooded turbine sites. There were no significant differences in bat or night migrant bird fatalities between lit (FAA L-864 obstruction lights) and unlit turbines.
The amount of area searchable under each tower and the numbers of towers searched per round during the project set-up stage were adjusted for when calculating the final fatality estimates. In addition, carcass removal (scavenging) and searcher efficiency studies were conducted to estimate the proportion of carcasses missed by the searchers and the proportion removed by scavengers within the 1-Day, 3-Day and 7-Day search cycles. These rates, along with the proportion of towers searched and the proportion of completed surveys to scheduled surveys were used to estimate the total number of fatalities likely to have occurred during the study period at all 67 turbines at the Noble Bliss Windpark.
The planned project start date was April 15, 2008. Due to late season snowfall in March, turbine areas were not accessible or amenable to carcass searches prior to mid-April 2008. All 1-Day site surveys were established and searched on April 21, 2008 (within a week of the project start date). Searching of 8 three-day and five weekly sites began on May 9, 2008. We awaited landowner approval of the two remaining weekly sites (26 and 30) and were able to search Site 26 on June 11, 2008. During the period of August 7 to September 18, 2008, we were restricted to searching the gravel area only of these sites. Upon receiving landowner approval, we were able to include Sites 26 and 30 in the weekly schedule on September 18, 2008.
By dividing the estimated number of incidents by the number of turbines and by 1.5 MW per turbine searched in each period, a rate of incidents/turbine and incidents/Megawatt was calculated for the study duration. In addition, by dividing the number of incidents/turbine by the rotor swept area (m2) and multiplying that figure by 2000m2, we are able to show the number of incidents/2000m2 rotor swept area.