1. The UK government has committed to obtaining 20% of the UK's energy from renewable sources by 2020 and to reducing CO2 emissions by 80% by 2050. In June 2008, the Crown Estate launched its "Round 3" leasing programme for the delivery of up to 25 GW of new offshore windfarm sites by 2020. European Directives such as the SEA, Birds and Habitats Directives, together with the United Nations Law of the Seas require that states accept responsibility for assessing the effects of major offshore development on the environment.
2. COWRIE previously published guidelines for ship and aerial survey of marine birds for offshore windfarm assessments (Camphuysen et al. 2004). The purposes of the current review are fourfold:
- to assess the extent to which these recommendations have been followed;
- to identify any differences in interpretation of the guidance between sites;
- to test the practicalities of using high definition cameras during aerial surveys;
- to provide more rigorous guidelines for the type of analytical techniques that should be used.