In science communications, as papers are published and projects reach their conclusion, we finally have the chance to shout about what we have done and why the world is different today. But, we also realise that sometimes good science is only of interest to those working in a specialised field. This can mean there is a temptation to try to sensationalise a story to make it more attention grabbing to everyone. Medical science is a perfect example where the wider public has a huge appetite for the announcement of cures rather than the myriad of vital breakthroughs that bring us ever closer to those cures. The publication of the Offshore Renewables Joint Industry Programme (ORJIP) Bird Collision Avoidance project is a timely reminder of how an attention grabbing headline can detract from good science as the media fixate on the dissonance between media release and published papers rather than what the story actually is.
The RSPB is supportive of well-sited renewable energy including offshore wind, which offers a vast opportunity to help the UK and other nations to achieve a de-carbonised energy sector and meet our climate emissions reduction targets. However UK and wider North Sea waters also support globally important seabird populations and other marine wildlife that are at risk from large scale deployment of offshore wind. We are focused on addressing these risks to ensure our ambitions for offshore wind deployment can be realized in harmony with nature, not in spite of it. It is for these reasons that we have been calling, for many years, for collaborative, evidence-based studies on seabird behaviour in and around windfarms to improve our understanding of the risks posed to these species. The Offshore Renewables Joint Industry Programme (ORJIP) Bird Collision Avoidance project is one such study, which we have been supportive of and in which we have been involved as a member of the Expert Panel. The valuable results of this impressive, ground-breaking study have just been published, but unfortunately the statement that accompanied the report misinterpreted its conclusions, and so press reporting of this work has been inaccurate.
The focus of the Bird Collision Avoidance project was to shed light on the potential impact of seabirds colliding with rotating turbine blades. Other impacts caused by offshore wind farms such as direct habitat loss, indirect habitat loss through barrier effects and displacement effects were outwith the scope of the study. Considerable uncertainty exists around each of these impact mechanisms and the extent to which they affect seabirds, none more so than the impact of collision mortality, so we welcomed this opportunity to collect new empirical data on this specific issue.
The study used a number of largely novel technologies to record bird behaviour at and around a small number of turbines at the edge of Thanet wind farm, located 12km off the coast of Margate, Kent, in the UK. Data were collected between July 2014 to April 2016 and the final project report was published on Thursday 19th April 2018. Whilst, as the report acknowledges, there were considerable limitations to the collected data, it did use a novel approach to shed new light on seabird avoidance behaviours in and around offshore wind turbines. However the project also made clear it would be wrong to extrapolate the results across the whole wind farm and therefore could not generate whole wind farm mortalities
This new dataset on seabird behaviour is an important step forward in minimizing the uncertainty around estimation of collision mortality impacts. However, a lot more work is needed before we can fully incorporate this into the assessment of collision risks of offshore wind projects. Such work is a recommendation of the project and is the focus of a new piece of work commissioned by a Government advisory body, the Joint Nature Conservation Committee. To understand the reasons why more research is needed requires a detailed look at how we currently assess collision mortality impacts. During the current environmental assessment process of offshore wind projects, the number of birds predicted to be killed through collision is estimated by Collision Risk Modelling. This modelling technique takes a number of input parameters, related to the turbines (e.g. blade size) and related to the birds (e.g. numbers present and flight height), and estimates the number of collisions that will occur. A key part of the model process is the application of a correction factor known as Avoidance Rate.
Avoidance Rate accounts for the discrepancy between predicted collision mortality and actual collision mortality. Such discrepancy arises because of natural variability and uncertainty in the input parameters, such as flight height and bird density, errors in the modelling process, errors in the model itself as well as any avoidance behaviour of the birds in response to the turbines. As such, “Avoidance Rate” is a misnomer; it is not exclusively related to avoidance behaviour per se. A number of studies have shown that Avoidance Rate has a disproportionate influence on the number of mortalities predicted by Collision Risk Modelling and there has been considerable debate around what its actual value should be (it is largely estimated) and how it could be better measured and refined. Improving understanding of the true value of the correction factor termed “Avoidance Rate” would allow us to predict collision mortality with greater confidence in the accuracy of models.
In contrast, the Bird Collision Avoidance project calculated what it called Empirical Avoidance Rates in order to distinguish these from the traditional Avoidance Rates as used in Collision Risk Modelling and described above. The project attempted to account for some sources of the variability and uncertainty that influence Avoidance Rates but was unable to quantify all of these. Attempting to compare the Empirical Avoidance Rates generated by this study with the correction factor know as Avoidance Rate that is used in collision risk modelling is akin to comparing apples with oranges.
The RSPB fully acknowledge this issue as being hugely nuanced and complex, however it is unfortunate that the press release that accompanied the publication of this study overstated and over simplified the applicability of the results. As a consequence the statement included figures on reductions in the risk of collision mortality posed by offshore turbines, figures which did not form part of the study nor are they found in the report itself and so had not been sighted by or agreed with the Expert Panel. The resulting press release has therefore drawn conclusions from the study that are simply wrong. This episode is tremendously frustrating as the very real gains of the project - an unprecedented amount of data on the behaviour of seabirds in and around an offshore wind farm, have now been overshadowed due to a misrepresentation of the project’s conclusions. We are committed to continuing to work with partners to use the data gained with a view to establishing more understanding of the behaviours of sea birds around offshore wind turbines. It remains criticially important to help the growing offshore industry minimize its impact on our globally important populations of seabirds whilst at the same time meeting our energy needs with clean renewable technologies.