In 2009, we refined the statistical set-up for the assessment of displacement effects on seabirds by wind farms in the Belgian part of the North Sea, more precisely at the Thorntonbank and Bligh Bank. The observed seabird densities were modelled through quasilikelihood estimation. The resulting models allowed to test for the difference in seabird occurrence between control and impact areas during the reference period. In case of Northern gannet, Sandwich tern, Common guillemot and Razorbill at the Thorntonbank, as well as for Northern gannet, Black-legged kittiwake and Common guillemot at the Bligh Bank, the delineated control area held highly similar densities compared to the impact area. This of course makes a good base for future BACI-comparison. Moreover, this modelling process is the first crucial step towards a power analysis, which will give insight in the probability of being able to statistically detect specified changes in bird numbers. In 2008, the first six turbines were installed at the Thorntonbank wind farm site. As expected, we were not yet able to discern any displacement effects. However, there are still about two hundred turbines to be installed at the Thorntonbank (C-Power), Bligh Bank (Belwind) and Bank Zonder Naam (Eldepasco), and as such it is too soon to draw any conclusions.