A wave energy test site is proposed for inshore waters off the west coast of County Mayo, Ireland. The test site has been selected for its high wave energy levels, due to full Atlantic exposure conditions. Some seabird data for the test site is available from past surveys of Irish waters. Detailed data is not available and baseline bird surveys as part of the Environmental Impact Assessment began in 2009. Surveys at sea followed standard European Seabird at Sea survey methods. Eight surveys were completed between October 2009 and October 2010, excluding the winter months. A total of 8,092 birds of 33 species were recorded. In March 2011 monitoring surveys began at the wave energy test site. The monitoring survey design has been adapted to detect effects of wave-energy related activities on bird densities within the immediate area surrounding each test berth. It is an experimental approach that uses test (berth) and control sites with pre- and post-activity monitoring. Because there are only two test berths, the ‘treatment’ sample size of our sampling design is limited to two in order to avoid pseudoreplication. This, coupled with natural variance in seabird numbers, means that power to detect small differences in seabird densities will be rather limited. Large scale differences should however be detectable. The key challenge has been how to develop an effective sampling strategy, within practical and budgetary limitations and for a novel development. Baseline survey work was financed by Tonn Energy Ltd.