VULNERABILITY OF SCOTTISH SEABIRDS TO OFFSHORE WIND

2.2 Proportion of biogeographic population in Scotland

The percentage of the biogeographic population (usually based on continuous distribution of the relevant subspecies, taken as the North Atlantic or European or Palearctic population as seems appropriate for particular species) occurring in Scotland was assessed from Forrester et al. (2007) where this statistic was reported, or by comparing the population estimate in Forrester et al. (2007) with the biogeographic population estimates given in del Hoyo et al. (1992, 1996) ( Table 1). Threshold values for scores were selected in order to classify species into similar numbers in each category. Thus scores were allocated as: 1 for less than 1%, 2 for 1 to 4%, 3 for 5 to 9%, 4 for 10 to 19%, 5 for 20% or more. Since this metric may vary seasonally, we used the highest seasonal score for each species.