Flying colours – can colour-ringing of kittiwakes improve our understanding of the impact of offshore wind developments?
To facilitate the sustainable expansion in offshore wind it’s necessary to understand likely impacts on wildlife. Of concern in the UK is the Black-legged kittiwake – a seabird that feeds in offshore waters near where it nests on cliffs. Our latest report presents the findings of a recent study, managed by JNCC and undertaken by a consortium led by the British Trust for Ornithology (BTO), which explores whether colour-ringing of kittiwakes can improve understanding of the impact of offshore wind developments.
To assess the impacts of wind farms on kittiwake colonies, and the population as a whole, we need to better understand their life cycle. Following individual birds throughout their life cycle using a conspicuous marking system helps record information of where kittiwakes nest, what colonies they visit during the breeding season, whether they have survived or not from one year to the next. Colour-ringing, which is safe for the birds, offers a useful approach to address these questions: birds are equipped with a rigid colour ring that has a unique combination of letters and numbers and can be viewed at a distance with binoculars, enabling that bird to be identified without recapturing it. However, before embarking on extensive studies, it’s important to estimate just how many kittiwakes need to be ringed and re-sighted, how often and where, in order to get reliable data from which to draw firm conclusions; this is where a feasibility study comes in.
Key results from the study found that a 5-year colour-ringing programme would be insufficient to get sufficient data on adult or juvenile survival rates, even under the highest levels of ringing effort. However, studies of 10 years or longer could provide sufficiently precise measures of survival, depending on the age class of interest. 20-year studies were required to detect a 4% step change in adult survival. The study also presented data that showed 83% of juveniles were re-sighted within 100 km of their natal colony during the breeding season.
Dr Orea Anderson, JNCC Project Manager, said: "These findings are crucial for the industry sector to decide when and how to fund future colour-ringing studies. We need to be formulating and funding long-term strategies for getting hold of seabird demographic data – short-term wins are just not supported by this type of approach, and investment in getting hold of this type of data needs a long-term and strategic approach. Demographic data sourced by colour-ringing schemes can provide vital information for the offshore wind farm and other marine sectors, as to-date, there are no other proven methods to get at this type of demographic data for kittiwakes."
Dr Helen Baker, JNCC Marine Species Team Leader, said: "This study, generously funded by Vattenfall, was identified as a priority knowledge gap by the industry-led Offshore Wind Strategic Monitoring and Research Forum (OWSMRF). The work of the Forum is important for clarifying what information on seabirds is most likely to improve certainty in impact assessments and hence help stakeholders to make decisions that address the needs for both biologically diverse and healthy seas around the UK alongside measures for tackling climate change. It’s really good to see a project idea from OWSMRF being funded and we hope that this is just one of many more that are taken forward by stakeholders over the next few years."
Jesper Kyed Larsen, Bioscience Team leader, Vattenfall, said: "Vattenfall is committed to engagement in research to better understand how wind farms affect seabirds. Working with JNCC and leading UK experts, this study explored the potential of a strategic colour-ringing programme in order to improve current modelling of how offshore wind farms can potentially affect kittiwake populations. The findings of this study will help direct priorities for further research to facilitate future offshore wind development without getting in the way of thriving seabird populations."
The full report is available from our Resource Hub.