The data set is indicating important spots where sea- and shore birds breed in the Baltic Sea area. This dataset depicts breeding areas of birds as polygon regions used for the BRISK project (Sub-regional risk of spill of oil and hazardous substances in the Baltic Sea, http://www.brisk.helcom.fi/). This dataset has been produced by COWI (http://www.cowi.dk). Based on data collected from Baltic sea countries (Denmark, Estonia, Finland (Finnish data Copyright: SYKE, The Finnish data is lacking small bays of the Finnish coastline. These bays are important for birds), Germany, Latvia, Poland, Russia, Sweden). The dataset includes data provided by the BRISK Project Partner organisations from various Baltic Sea countries. The detailed documentation of what partner provided what data is given in the Annex of the document: 70618-3.1.2.2 Data Collection Report. About 20 species of seabirds breed along the coast of thee Baltic. The Archipelago areas in Finland and Sweden are the most important breeding areas. They are very vulnerable to oil spill. The data includes important spots where seabirds nests.