Potential impacts of offshore wind farms on gannets

27 January 2023

New blog by Dr Jude Lane, Conservation Scientist, RSPB

Power generation from offshore wind is vital to enable a shift away from fossil fuels and make it possible for the UK to achieve its net zero targets by 2050. The UK is a world leader in offshore wind but there are clear challenges to overcome to ensure that healthy seas and wildlife go hand in hand.

Seabirds are top predators in the marine ecosystem and excellent indicators of the health of our seas, but they are also potentially at risk from offshore wind farms. Risks to seabirds include colliding with turbine blades and displacement from foraging areas or travel routes. Gannets have been identified as being one of the seabirds most at risk from offshore wind farms due to the proximity of their colonies to developments and how high they fly.

My work as a Conservation Scientist at the RSPB includes monitoring the survival of Bass Rock gannets to identify any population impacts from the developments in the Forth and Tay region of the North Sea. I also collect data on how gannets behave at sea to better inform predictions about the impact of future developments on gannets.

Survival monitoring is a good way to establish if there are any population level impacts occurring due to increased mortality from collision with turbines. Since 2010 a small proportion of breeding adult gannets on the Bass Rock have been marked with coloured leg rings engraved with a unique code, work led until last year by the University of Leeds. Each summer I return with colleagues to make visual searches for these colour ringed birds, keeping a record of those that are seen and building up a dataset of survival rates from one year to the next. This data allows us to compare survival rates prior to and after construction of the turbines. In recognition of the value of this work and as part of post-consent monitoring requirements, developers of three of the offshore wind farms closest to the Bass Rock; the under construction Neart na Gaoithe (EDF Renewables and ESB) and Seagreen (SSE Renewables and Total Energies), and the proposed Berwick Bank project (SSE Renewables), have funded this work since 2020.

Tracking gannets using GPS tags is a useful way of understanding the behaviour of gannets at sea, where they go and what they do there. Tracking work has also been taking place at the Bass Rock since 2010, highlighting the overlap between where gannets go and offshore wind farm sites in the North Sea. Again, in recognition of how valuable this information is, in 2020 Neart na Gaoithe Offshore Wind Ltd, Seagreen Wind Energy Ltd and SSE Renewables’ Berwick Bank project, agreed to fund the tracking work so that detailed data on gannet behaviour could be collected within the footprints of the developments prior to construction.

The above graphic is taken from Lane et al. 2020, the windfarm boundaries shown were current at the time of paper publication.

Fieldwork 2022

In March 2022 I was excited to make my first trip of the year out to Bass Rock to install equipment that allows data collected by GPS tags to be downloaded without having to re-catch the birds. I’d never visited an empty Bass Rock before, it was eerily quiet without the thousands of birds that completely overload your senses later in the year, but the handful of early birds milling about hinted at the imminent arrival of the residents that would bring the rock to life again.

Our trip to fit GPS tags took place in late April during which we successfully fitted tags to 10 birds. The tags were designed and manufactured by the University of Amsterdam and collect not only GPS location data but also data on their behaviour and flight height from an in-built accelerometer and pressure logger. We then planned to return in July to deploy some more tags on birds raising chicks and to undertake the visual searches using binoculars, for birds marked with coloured leg rings.

HPAI outbreak

At the beginning of June, we heard the news we had all been dreading, unusual numbers of dead gannets being washed up along the coast. We had been hearing about the Highly Pathogenic Avian Influenza (HPAI) outbreaks in great skua and gannets in Shetland and Orkney but had been naïvely crossing our fingers and hoping that the virus might not make it as far south as the Bass Rock. Sadly, carcasses collected from the Bass Rock in early June by the Scottish Seabird Centre were tested by with the Animal and Plant Healthy Authority (APHA) and confirmed to be positive for HPAI.

We quickly modified our plans to enable us to record the impact of the virus on the Bass Rock gannets through visual observations, specifically focusing on the population of colour-ringed birds. This involved increasing the number of visits to the colony from what we had previously planned, the funding for which was provided by the wind farm developers. Knowing the colony so well and having these identifiable individuals meant we were in a unique position to record the unprecedented impact of the HPAI outbreak.

Whilst on the Bass Rock we followed strict health and safety and biosecurity protocols, drawn up in conjunction with the Animal and Plant Health Authority. These protocols ensured that we didn’t risk causing additional spread within the colony or from the colony to the mainland, and to ensure our own safety. These measures included wearing disposable overalls, masks, rubber boots and ensuring stringent levels of hand and equipment sanitisation.

On a personal level, it was a difficult summer. Watching birds suffering and seeing nests being abandoned daily, knowing there was nothing that could be done to stop it was awful. However, I was grateful of the opportunity to make the observations and collect the data we did that will contribute to informing how gannet populations respond to this and potential future outbreaks of avian influenza.

For all of us who love and care about the Bass Rock gannets, it was terrible to see the impact the virus had, but to end on a more positive note, there were some glimmers of hope in that we did see adult birds that remained healthy and chicks that fledged. What will happen in 2023 is impossible to predict, but whatever happens we will be monitoring it closely in conjunction with the Scottish Seabird Centre and all our partners and funders. In the meantime, we are currently in the process of writing up the findings of the monitoring and work undertaken during the 2022 outbreak, and I hope to be able to bring you news of this later this year.