'Kittiwakery' Nesting Towers
Compensation For Offshore Wind Developments
Habitats Directive (IROPI) For Offshore Wind
Offshore wind farm projects are required to offset the predicted collision mortality of kittiwakes from turbines to comply with the Habitats Directive (IROPI rules). On shore nesting structures are a preferred compensation measure and FLI has worked with global authorities in the field to develop an off-the-shelf compensation tower system known as ‘kittiwakery’ to meet the needs of the industry.
IROPI compliance specialists Shoney Wind Limited (SWL), produced a design brief through consultation with the Institute for Seabird Research and Conservation (ISRC) and EcoNort. Then, SWL brought in FLI as design engineers to develop, manufacture and install kittiwake towers. FLI and SWL were supported by the Offshore Wind Growth Partnership (OWGP) in developing a prototype in mid 2022. The first in-service tower was built for RWE at Gateshead in early 2023, demonstrating a rapid turnaround of the prototype into a real solution with all feedback taken on board. Therefore, this multi-discipline collaboration has succeeded in producing a high-functioning and economically viable solution meeting a need within the sector.
Colonisation Success and Higher Fledging Rates
The research carried out by SWL and the ISRC has produced a set of site selection, site survey and micro-climate creation protocols that deliver higher colonisation and fledging rates.
Full access for ornithologists to the nesting modules is via the stairwell, so that there is no need for rope access or elevated work platforms.
Hatches, windows and apertures facilitate safe monitoring, biometrics, ringing and supplementary feeding, at scale, from inside the tower.
Modular Design Flexibility
The design enables the experimental and developmental changing out of ledge types and sizes from inside the tower, with hand tools, to establish the impact on nesting of various configurations. Any under-performing faces can be altered at minimal cost, to improve fledging success.
Towers are secure from land-based predators and unauthorised access.
Additional capacity can be added to the existing structure via additional levels of nesting modules.
The towers, complete with their foundations, can be quickly and easily re-located if they are not colonised, removing investment risk.
Rapid Installation and Low Cost
The off-the-shelf product system offers site-specific solutions at minimal design cost. Tower heights, capacities and a range of nest ledge designs are existing options.
Screw pile foundations avoid all use of concrete (subject to ground conditions). This means no wet trades or chemicals. There is no excavation or cart away, which reduces the environmental impact. The process is clean and quiet with minimal vibration.
The foundation can be installed in a week and the tower takes 2-3 weeks to erect, including the nesting modules.
Both the tower and the screw pile foundation can be relocated. They can also be easily and entirely removed from site and completely recycled at end of life, which is another ‘Green’ benefit.