A study led by BTO uses data from GPS tracking and other research to identify the likelihood of seabirds of 27 species interacting with areas of sea earmarked for 41 new offshore wind farms around the UK.
The UK’s seabirds have experienced substantial population declines in recent years, thanks to many pressures including overfishing, climate change, severe weather and most recently, Highly Pathogenic Avian Influenza. Another possible and growing pressure is the construction of offshore wind farms, which can displace birds from former marine feeding grounds, act as a barrier to movement or pose a risk of death if birds collide with them. However, the use of green energy is vital in mitigating climate change, so information on where to place turbines to minimise adverse effects on seabirds is critically important.
In 2012, BTO published an influential review using information from tracking studies and marine surveys to estimate how far seabirds of several species travel from their colonies to feed during the breeding season. These so-called foraging ranges were used as a screening tool to assess the potential impact of offshore wind farms on breeding seabirds. Since this review, there has been a rapid expansion in seabird GPS-tracking studies, so the evidence base for assessing the interactions between seabirds and wind farms is much improved.
This study updates the 2012 review. Among other findings, it shows that thanks to tracking data, the foraging ranges for eight species, including Kittiwake and Puffin, are more than 50% larger than those calculated previously. This highlights the danger of basing screening processes for offshore developments on limited data. With the continued expansion of tracking studies, it is important that these data are updated regularly in order to ensure that all decisions can be made on the basis of the best available evidence.
One of the key emerging pressures facing seabird populations is the development of offshore wind farms (OWFs). Estimates of seabird foraging ranges have been widely used to assess the potential of birds from specific colonies to interact with planned OWFs, and to apportion any predicted impacts to breeding populations. Ideally, these foraging range data would be site-specific estimates, collected from the colonies of interest using tracking devices within a timeframe of relevance to the planning process. However, logistical constraints linked to site accessibility, the availability of tags and suitably trained personnel to deploy them and the need to avoid deleterious tag effects mean that this is not always possible. Consequently, many assessments rely on previously published estimates of seabird foraging ranges. The rapid development of tracking technology means that there has been a substantial increase in both the number of individual birds and the number of seabird breeding colonies from which tracking data originate, increasing uncertainty as to whether assessments are based on the best available evidence. To address this, we carried out a systematic literature review of tracking studies for 27 species. By accounting for recently published data, we are able to generate more robust estimates of foraging ranges for many of these species. In some cases, these were more than double previous estimates. We investigate the potential for birds to interact with 41 new wind farms planned for UK waters. Whilst the collection of site-specific data to inform assessments for future OWFs is desirable, generic values, such as those presented here, are likely to play an important role for the foreseeable future. We discuss the limitations and issues to consider when using generic foraging ranges, and highlight the importance of having access to consolidated up-to-date information within the decision-making process.
Notes
This work was overseen by a steering group involving Melanie Kershaw (Natural England), Alex Robbins (Scottish Natural Heritage), Matthew Murphy (Natural Resources Wales), Orea Anderson and Julie Black (JNCC). The authors thank Julie Black for help with accessing data collected by JNCC describing tern foraging behaviour and, Ruben Fijn (Bureau Waardenburg) for help accessing Sandwich tern and Great Cormorant foraging data from the Netherlands. The work was funded by The Crown Estate as part of a series of projects being conducted to build the evidence base for the plan-level HRA for Offshore Wind Leasing Round 4. The project was managed by NIRAS Consulting Ltd. We thank Ed Salter (The Crown Estate) and Sara Pacitto (NIRAS) for their support of this project.
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