296 © British Birds 102 • June 2009 • 296–341 ABSTRACT This is the fourth major review of the status of birds occurring in the UK, Channel Islands and Isle of Man.W e present Red, Amber and Green lists of conser vation concern based on assessments using objective listing criteria and using the most recent data.The listing criteria assess global conser vation status, historical population decline, recent population decline (numbers and geographical range), European conser vation status, rarity, localised distribution, and international impor tance of populations. Some changes have been made to the criteria since the last assessment, and the effect of these changes is discussed. O f 246 species assessed, 52 (21.1%) have been placed on the Red list, 126 (51.2%) on the Amber list and 68 (27.6%) on the Green list. Eighteen species have moved onto the Red list since the last assessment in 2002, and six have moved from Red to Amber. Birds of C onser vation Concern 3 The population status of birds in the U nited Kingdom, C hannel Islands and Isle of Man M ark A. Eaton, Andy F. Brown, David G. N oble, Andy J. M usgrove, Richard D. H earn, N icholas J. Aebischer, David W . Gibbons, Andy Evans and Richard D. Gregory Arctic Skua Stercorarius parasiticus Alan H arris BB June 2009 - edit pages 22/5/09 15:47 Page 296