27 Mar Onshore Wind Research: nightjar, red kite and curlew studies
In recent years BSG Ecology has completed night jar and red kite research to address information gaps in onshore wind farm impact assessments. As ecologists we see value in committing time and resources to these sorts of study, as they make our assessment work more robust, and demonstrate that the industry is keen to understand and quantify impacts accurately, thereby building relationships and trust with nature conservation stakeholders. The outcome of both of these projects work were publicly accessible research reports.
The nightjar and red kite projects led to a request from Natural Resources Wales (NRW) for BSG to co-ordinate a GIS-led data collation exercise on breeding curlew and other waders in Wales. This involved accessing data held by renewables developers.
An overview of these projects and links to the reports resulting from them are below.
Nightjar Research
BSG completed a review of the findings of over 30 years of pre and post construction nightjar survey and monitoring at wind farm sites in west, south and north Wales respectively: Pen y Cymoedd (Rhondda Cynon Taf and Neath Port Talbot County Boroughs); Brechfa Forest West (Carmarthenshire) and Clocaenog Forest (Conwy and Denbighshire)
Studies at all three sites involved repeat survey of churring males and the capture and radio tracking of birds (to assist in locating nest sites). The review established that the wind farms have increased the breeding habitat available to nightjar at the sites, that birds bred productively within the operational wind farms (including very close to the turbines) and that there was little evidence of collision fatality. Pre and post construction data showed that there appears to be considerable natural variation in breeding numbers between years.
The work was published in Milvus, the Journal of the Welsh Ornithological Society in November 2025, and is available here: Operational Effects of Wind Farms in Commercial Plantation on European Nightjar
Red Kite Research
BSG identified the need for a study to determine the extent to which consented, proposed and aspirational wind farm developments were likely to result in cumulative impacts on the re-established Welsh red kite population. BSG collaborated with the British Trust for Ornithology (BTO) and Cardiff University to complete Population Viability Analysis work to explore the question. This involved accessing data on red kite from raptor workers and the Welsh Kite Trust, wind farm monitoring reports and information on current and future schemes from wind farm developers.
An initial study, published in 2024, was supplemented by further work in 2025 that responded to specific queries from NRW with regard to red kite populations associated with Special Protection Areas (SPA). Modelling results indicated that cumulative collision fatality had a very low probability of affecting populations at any geographical level, including the populations within the SPAs.
The work was published as BTO Research reports (see links below) and in an article published in Milvus.
Original Report: Modelling population-level impacts of wind farm collision risk on Welsh Red Kites
Curlew Research
BSG completed a GIS-led project to source, standardise, collate and provide Wales-wide data on breeding curlew (and other waders) that had been collected to inform renewables projects to NRW. The purpose of the work was to inform NRW’s ongoing efforts to drive curlew recovery, and in particular help refine the scope of a repeat survey of breeding waders in Wales in 2026.
The project resulted in the collation, standardisation and provision of GIS data for over 700 square kilometres of land. It was sourced from 53 proposed wind and solar projects, with information provided including wader territories, null results, areas surveyed, technique employed and number of visits completed. NRW subsequently made the data (no site details or developer information was included) available to the BTO who used it to design the approach to survey in 2026.
The results of the work were issued to NRW and are confidential.
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For advice on wind farm related bird or ecology issues anywhere in the UK please contact us at info@bsg-ecology.com