Alternative Energy Draft EA - NASA Visitor Center at Wallops Flight ...

Affected Environment
For the once-per-week observations throughout the 52-week period, biologists visited both
observation sites at least once per week for a minimum of 15 minutes per day between 7:00 a.m.
and 9:00 a.m. at each location to record avian activity. Data were recorded for birds observed
within a 1-kilometer (0.62-mile) radius of the point count locations. Data for each avian
observation included: species, number of individuals, and behavior of individuals (to include
altitude, flight direction, feeding vs. flying/migrating, resting, etc.).
During migration seasons, the biologists conducted 15-minute avian observations at least twice
weekly between 7:00 a.m. and 9:00 a.m. at each location at the same two observation points
referenced above. During peak migration days, biologists supplemented these data by conducting
observations at the U.S. Navy building mast tower, which offers unobstructed, panoramic views
of the Wallops Island air space (including the rotor sweep areas of the proposed turbines). The
survey team targeted fall and spring days when weather front movement was conducive to
migratory activity and conducted their spot observations during daytime hours (between 9:00
a.m. and 4:00 p.m.). Data collected during migration season surveys included the date and times
of observations, species observed, numbers of individuals, and behavior. Behavioral information
includes the path where birds were flying in relation to the proposed turbine area(s), height of
flight (below, within, or above the rotor height zone), perching behavior, hunting behavior, etc.
Local weather data, including temperature, sky conditions, wind direction, and wind speed, were
also recorded.
Avian Fatality Searches at Existing Towers
NASA used three existing towers on Wallops Island as surrogates for wind turbines to study
avian fatalities. By studying fatalities at these tall structures, an understanding of the nocturnal
and diurnal birds that use the airspace above Wallops Island was acquired. One guyed (North
Boresight, 47 meters [155 feet] tall) and two unguyed towers (South Boresight, 47 meters [155
feet] tall and South Meteorological Tower, 102 meters [335 feet] tall) were used for observations
(see Figure 12).
Fatality searches were conducted as soon as possible after sunrise between October 1, 2008, and
September 30, 2009. The intensity of searches was greater during the peak spring (April to early
June) and fall (August to October) bird migration seasons. Searches took place three times per
week during the migration seasons and one time per week during the remainder of the year; the
length of time for each search was not reported. At the North Boresight Tower, the search area
extended outward to the full extent of guy wires (approximately 18 meters [60 feet]). At the
South Boresight Tower and South Meteorological Tower, which have no guy wires, the search
areas extended from the tower base outward to 80 percent of the tower height (approximately 38meter
[125-foot] and 82-meter [268-foot] radii, respectively). The maximum area searched was a
rectangle with transects separated by 7 meters (23 feet). All 335 square meters (3,600 square
feet) was searched at the North Boresight Tower; a portion of the areas for the South Boresight
Tower and the South Meteorological Tower was searched as shown on Figure 4 in Appendix A.
All carcasses (i.e., feathers or clumps of feathers with flesh attached or loose tail or primary
feathers not expected to come from molt) were recorded as fatalities.
In addition to fatality searches for bird carcasses beneath the existing towers, searcher efficiency
and carcass removal trials were also conducted. The Avian Study Final Report (Appendix A)
contains more detailed explanation of the searcher efficiency and carcass removal trials.
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