The wind turbine has received some of the most heated and angry opposition any technology has had to endure in many years, and as we continue to study the effects of wind turbines and wind farms as a whole, we continue to discover that all of this negative attention has been misplaced.
Two recent studies disproved the ideas that wind farms affect health and property values, and now a new review by the British Trust for Ornithology and the University of Highlands and Islands’ Environmental Research Institute has found that 99% of seabirds are likely to alter their flight paths to avoid collision with offshore wind turbines.
Before highlighting the disclaimer, let’s dwell on those figures for a moment.
The study highlighted three scales of avoidance a bird may attempt:
Interestingly, the report does not focus on macro-/meso-avoidance, but rather macro-/meso-response — the idea that some birds may in fact avoid, but that others are specifically attracted to the wind turbines. In this way, for example, macro-response encompasses both those birds which make a decision to avoid the wind farm or turbine, and those who make an opposite choice. However, micro-avoidance refers to a more immediate avoidance, or “last-second” alterations to flight plans. This could be the case for birds which are attracted to wind turbines or farms for various reasons — such as roosting — or who need to take last-second action as a direct result of adverse weather conditions.
Meso-response is a bird’s response to turbines within a wind farm, such as cormorants who might consider the base of a wind turbine — below the reach of the turbine blade — a suitable place for nesting.
As such, the above figure, courtesy of Desholm & Kahlert (2005), on Avian collision risk at an offshore windfarm. Biology Letters 1: 296-298, represents flight trajectories of migrating waterbirds within and outside an offshore wind farm.
The disclaimer is a necessary part of this news, however. Aonghais Cook, Research Ecologist at BTO, who led the study, noted that it “is important not to get lulled into a false sense of security by these figures. Whilst 99% of birds may avoid turbines, collision may still be a significant risk at sites with large numbers of birds. Furthermore, there are still a number of key gaps in knowledge for some vulnerable species.”
So, as we have seen time and time again, the more we learn, the more we realise we need to learn. In the interim, however, it’s relatively safe to say that wind farms are not going to be competing with the average cat for bird-deaths.
Top image credit: Graeme Maclean, via Flickr