The maps below shows 10-km squares and whether more than or less than 8 tetrads have been surveyed at least once in either winter or the breeding season during 2007-11. Yellow indicates less than eight tetrads surveyed; Red indicates 8 or more surveyed in that 10km square. Our aim is to colour all parts of the map in yellow or red. To help make that a reality, go to the main Atlas pages for more detailed descriptions of the Atlas survey and mapping methods.