A radar and ESAS study of seabird activity on a floating offshore wind power project
Creators: name: Machado, Rui
name: Nicolau, Pedro G
name: Moreira, Pedro
name: Gomes, Sara
name: Cardia, Pedro
name: Cidraes-Vieira, Nuno
name: Oliveira, Ricardo
name: Repas-Goncalves, Miguel
Publisher: name: Zenodo
Year: 2023
Subjects: Seabird activity
Floating wind power project
Birdtrack
Radar survey
ESAS survey

description: Offshore wind energy is rapidly expanding with significant impact on seabirds. Assessing those impacts requires methods to comprehensively survey seabird activity in the marine environment capturing both the annual and monthly variation as well as the circadian. We compared the results from seabird monitoring programs conducted at the Windfloat Atlantic II offshore floating wind power project where radar surveys and boat based ESAS surveys were conducted simultaneously on the three turbines (8.4 MW each), located 18km from the coast in offshore waters of northwest Portugal. The two datasets were collected between November 2020 and June 2022. The radar data was obtained on a long-range Birdtrack S-band radar system operating on surveillance mode at a range of 4,5 km which delivered continuous data on bird activity, flight direction, flight speed and behaviour. The ESAS survey data was obtained from six boat campaigns each year which delivered data on bird activity, species, number of individuals, flight direction, flight height and behaviour. Both Birdtrack radar and ESAS data showed higher seabird activity during pre- and post-nuptial migration and during winter. The observed flight directions were coherent with phenology of the species occurring in the region where most bird targets headed southwards during autumn and winter but headed mostly northwards during spring. Moreover, most radar targets were recorded during the day in spring, summer and winter, peaking in the morning and late afternoon. Noteworthy, the radar data shows an increment in bird activity at night (64%) during autumn most likely associated with nocturnal seabird migration. This information in unobtainable using standard visual monitoring methods, such as ESAS, and represent a novel aspect of seabird activity monitoring at offshore wind farms. Nocturnal activity of seabirds is known, in particular during migration, thus posing vulnerability of seabirds to collision with offshore turbines. The array of species likely to be active at night during migration in the region include gulls, terns, norther gannet and shearwaters, including the Critically Endangered Balearic Shearwater. Understating the circadian movement patterns during the 24h-period is crucial to carefully evaluate, assess and prevent impacts on seabirds. Monitoring seabirds with Birdtrack radar technology allowed further to characterize seabird activity during the night revealing an important nocturnal use of the area during migration. Key words: Seabird activity, Floating wind power project, Birdtrack, Radar survey, ESAS survey <em>SPECIES-SPECIFIC RESPONSES OF ONSHORE AND OFFSHORE WIND ENERGY PROJECTS</em> <em>Oral presentation</em><br> <em>Abstract code: EPIQEXYM6AOI586GT</em> <strong>A RADAR AND ESAS STUDY OF SEABIRD ACTIVITY ON A FLOATING OFFSHORE WIND POWER PROJECT</strong> <strong>Rui Machado<sup>1</sup>, Pedro Moreira<sup>1</sup>, Sara Gomes<sup>1</sup>, Pedro Cardia<sup>1</sup>, Nuno Cidraes-Vieira<sup>1</sup>, Ricardo Oliveira<sup>1</sup>, Miguel Repas-Goncalves<sup>1</sup></strong>, <sup>1</sup>STRIX, 4450-286 Matosinhos, Portugal<br> miguel.repas@strixinternational.com
description: Conference presentations and posters are typically about preliminary findings and are usually followed up by a detailed paper. This poster is based only on its abstract and may offer limited information. Please contact us for the detailed project brief, which may offer additional information that you can utilize for your research. This project was commissioned to STRIX by the Windfloat Atlantic developers Windplus, Ocean Winds, Repsol and Principal Power.