2004-2006, British Trust for Ornithology, Greater Gabbard Offshore Wind Farm, The Potential Effects on Birds series https://portal.medin.org.uk/portal/start.php?tpc=015_6191a0c8a74d52039398e0e6ee7f2619 Greater Gabbard Winds Ltd (GGOWL) has contracted the British Trust for Ornithology (BTO) and Environmentally Sustainable Systems (ESS) to undertake surveys and to assess the impacts of the proposed wind farm on bird populations. The North Sea and Suffolk coast are important areas for many waterbirds including divers, seaducks, gulls and auks. Offshore surveys were carried out between February 2004 and April 2006 to asertain the abundance and distribution of birds in the "footprint" area of the proposed wind farm, plus an extended "reference" survey area. Aerial and boat surveys were used in accordance with COWRIE recommendations. Centre for Marine and Coastal Studies Ltd (CMACS) was commissioned by Greater Gabbard Offshore Wind Limited (GGOWL) to analyse marine mammal sightings data collected by ESS Ltd during site-specific surveys of the proposed offshore wind farm development area. These data were used to support the project baseline description of marine mammals and the subsequent environmental impact assessment. The purpose of this report is to provide the marine mammal sightings data. Survey methods and all analyses used to inform the marine mammals baseline and to support the impact assessment are detailed in the environmental statement (GGOWL 2005). 20040101 20060601