Concerns monitoring data. The Offshore Wind Park Egmond aan Zee is the first offshore wind farm to be built in the North Sea off the Dutch coast. The park consists of 36 wind turbines, each with a capacity of 3 MW. The location of the park is 10 to 18 kilometers off the coast at Egmond aan Zee. It is a demonstration park: The knowledge and experience developed here is important for the further development of offshore wind energy. This involves technology, ecology, economic and social feasibility. NoordzeeWind, a consortium of Nuon and Shell and owner of OWEZ, won the tender for OWEZ in combination with the so-called MEP-NSW research programme, a research program set up by the national government in 2006. This program contains learning objectives for the development of offshore wind. The MEP-NSW has made an important contribution to the learning objectives of offshore wind energy. The monitoring and evaluation program focuses on the following ecological issues: • Birds: flight patterns, presence, intensity, season, day/night in connection with the assessment of collision risks: Birds: disruption of habitat/foraging area, barrier effect. The influence of underwater noise on fish and marine mammals. The variation and densities of marine life and its functioning as a refugium.