The Lewis Peatlands Special Protection Area (SPA) was classified under the European Council Directive on the Conservation of Wild Birds (79/409/EEC) on December 7 2000; the site encompasses an area of 58,984.23 hectares.The relevant international population by which the importance of any bird species on an SPA can be assessed is expressed in terms of the biogeographic population from which it is drawn or is a part of.