Guillemots and razorbills are among the seabirds considered most vulnerable to displacement by offshore wind farms. Due to the challenge of tracking seabirds for a prolonged period of time, there is a knowledge gap when it comes to following their movements during non-breeding season and assessing the impact of offshore wind developments on these movements.
This project will use the geolocator tags to collect movement data over several years. The tags are small enough to be fitted to a leg ring and have a battery life of up to five years. They can record light intensity and sea surface temperature (SST) on a time base memory chip. The combination of both measurements allows for a refined position estimate for guillemots and razorbills, particularly because SST varies considerably in different locations.
Both species have long lifespans and adults come back to the same nest site year after year. A number of ringing groups regularly visit accessible colonies and this project will make use of their knowledge and expertise to support in attaching tags to birds’ legs. Once the birds return to the same spot in the years after, the tags and data they have captured will be recovered and analysed by a PhD student.
Initial deployment of the tags was carried out in summer 2017 with a combined total of 436 tags deployed at ten colonies from Canna to the Farne Islands. A PhD student has been appointed to this project from June 2018. We plan to recover some of these tags in June-July 2018, and to deploy another 200 or so tags at these and another group of colonies. This should mean that preliminary maps of migration routes from different colonies used in 2017-18 will be available in late 2018.
Ultimately, this should inform any displacement concerns and allow for less uncertainty in impact assessment for these species which will be key to planning for future developments.
Professor Bob Furness, Principal Ornithologist at MacArthur Green, said: “It is very exciting to be able to deploy tags on guillemots and razorbills to learn about their migration routes and wintering areas. Until now, our knowledge of their migrations has mainly come from recoveries of ringed birds found dead on beaches in winter, which can give a very biased picture. This project will allow us to track the routes used by birds, and which areas they spend time in throughout the winter.
“We are particularly interested to find out if these migrations differ between birds from different colonies, and whether individuals use different areas from year to year or consistently go back to favourite locations. That knowledge will not only help in assessment of the impacts of offshore wind farms but will also help us understand how best to conserve these internationally important seabird populations that are an iconic part of Scotland’s wildlife heritage.”