The immediate study area and the main subject of this chapter is the footprint of the Islay Offshore Wind Farm site, which covers an area of 94.6 km2. Boat-based surveys of the site included the site footprint plus an additional 4 km buffer covering a total area of 311.8 km2 (hereafter described as the ‘site+buffer’). The width of the buffer was based on the theoretical displacement distance of auk species determined at constructed offshore wind farms in Danish waters (Petersen & Fox, 2007). Although it has subsequently been shown that auks habituated to the constructed wind farm and displacement was only short term (DONG et al., 2006), this distance was deemed sufficient to determine any gradient effects in bird density which might occur during or post-construction. Beyond the site+buffer, an extended study region was defined in order to understand the zone of influence of the proposed development on the ornithology of the surrounding area during the breeding, passage and wintering periods. As bird behaviour and distribution differs between these periods, it was appropriate to define the relevant area for each period in a different way and, where necessary, on a species by species basis. The methods employed for doing this are described in the following sections.
2012, Islay Offshore Wind Farm, Environmental Statement, Interim Ornithology Chapter