Supplements to the AOS Checklist of North American Birds, 7th edition, are published annually in the July issue of Ornithology (formerly The Auk). Each AOS checklist supplement incorporates changes accepted in proposals considered by the North American Classification Committee (NACC) from mid-year of one year to mid-year of the next. Prior to 2012, proposals were numbered by the first year of the two years (i.e., proposals numbered 2011 covered the year 2011–2012, proposals numbered 2010 covered the year 2010–2011, etc.). Beginning with 2012, proposals are numbered by the second year which corresponds to the published supplement (i.e., proposals numbered 2013 cover the year 2012–2013 and are published in the July 2013 issue of The Auk). Because of this change, no proposals are numbered 2012.