|Tree Swallow via Marshall Segal on Flickr|
TransAlta has just released its fourth Report on bird and bat monitoring from its Wolfe Island wind plant located on the west side of Wolfe Island, near Kingston Ontario.
The report affirms that TransAlta’s Wolfe Island Wind Energy plant is one of the most destructive for birds and bats in North America.
Easily visible from the Kingston waterfront, the 86 turbines continue to kill large numbers of birds and bats. Most of the casualties described in the report are the same species reported in the three previous TransAlta studies of bird and bat deaths at their Wolfe Island plant, with Tree Swallow and Purple Martin at the top of the list, and including Bobolink and Barn Swallow, both listed as Threatened by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC).
All of the Ontario swallow species listed in the report are suffering long-term population declines, which makes the unforeseen impacts of the wind energy plant on wildlife all the more troubling. Only two raptors casualties were reported, which may be more a reflection of reduced search efforts in this period, although winter raptor surveys on the island revealed higher numbers of several species compared with the previous year, in particular, Rough-legged Hawk and Short-eared Owl. However, raptors do not appear to be using the habitat on which the wind plant in the north-west corner of the island is situated, and where the turbine density is highest. Three migratory species of bats, including Hoary, Eastern Red, and Silver-haired, comprised the balance of the bat casualties. Unlike birds, which are struck by the fast spinning tips of the turbine blades, bats are killed due to “barotrauma,” a condition caused by the sudden change of pressure around the blades that result in damage to their lungs.
The report presents the findings of monitoring programs that began in June 2009, which will produce reports approximately every 6 months over the first three years of the wind plant’s operations. The current report represents the third six-month period of monitoring. (The first Report was for a two-month period). Several aspects of the plant’s impact on birds and bats are monitored, including casualty rates of birds and bats, displacement of waterfowl and distribution and behaviour of raptors.
The results of the report reinforce the significance for birds and bats of the open scrubland habitat on the offshore islands at the eastern end of Lake Ontario, and onshore alvar habitats such as those found on Ostrander Point in Prince Edward County or Amherst Island. Wind energy plants, transmission towers, and other types of developments that put birds and bats at high risk should be excluded from these significant areas. All of Wolfe Island and a portion of its surrounding waters were recognized as a globally significant Important Bird Area (IBA) by BirdLife International’s Canadian partners, Nature Canada and Bird Studies Canada.
Taken together, the reports show that TransAlta’s Wolfe Island Wind Energy plant has one of the highest annual rates of casualties, reporting 16.5 birds per turbine and 43.7 bats per turbine, based on the 6 month study period from July 1 to December 31, 2010. Over a year, this would amount to approximately 1,500 birds and about 3,800 bats. Only one wind plant of the 45 reported on in a landmark 2010 study cited in the TransAlta Report by the US National Wind Coordinating Committee killed more birds per turbine. That plant, the Buffalo Mountain Wind Farm in Tennessee, which is consisted of only three .66 MW turbines at the time of the study, and so makes for a poor comparison. Most wind energy projects have much lower casualty rates for birds and bats.
It is also becoming clear that the July to September period (when the Swallows congregate and the bats migrate) is the most devastating for birds and bats. In my view, it is time that TransAlta implement serious mitigation, and turn off the turbines during this high risk period. This would save the lives of hundreds, if not thousands of birds and bats.