Windfarm developers are obliged by law to undertake pre and post-construction surveys of the seabird population at and in the vicinity of proposed windfarm sites. The two standard tools for these surveys are aerial and ship-based surveys. Of these two, aerial surveys are the more affordable, and provide the most practical and cost effective means for gathering contemporaneous data on a large area due the limited speed of boats.
In a previous COWRIE study, HiDef Aerial Surveying Ltd. demonstrated the feasibility of applying high definition video technology to seabird surveys through trial surveys. This trial demonstrated the ability to use the HiDef surveying technique for surveying sensitive species such as common scoter in shallow waters.
In order to demonstrate the techniques capability further, to further show the feasibility of using the technique for such sensitive species in inshore areas and to provide further confidence in the technique as a practical tool for windfarm surveying, COWRIE commissioned a further trial in the Rhyl Flats area. This trial was successfully completed over two days in April 2009. The objective of this report is to record and analyse the output from this trial.
The aim of this trial was to demonstrate the ability to identify red throated divers from video data. Example images of divers are shown in section 3.3. A total of 15 divers were identified using the HiDef survey technique giving a population estimate of 75. This is in line with the population estimates described in ‘Aerial Surveys of Waterbirds in Strategic Wind Farm Areas: 2004/05 Final Report (May 2006)’.