North American Birds: ABA Code 3 - Page 3

For its checklist, the American Birding Association assigns a code number for each bird that has been recorded in North America; generally speaking, the higher the code number, the rarer the bird. As defined by the ABA on its website, code 3 birds are "species that occur in very low numbers, but annually, in the ABA Checklist Area. This includes visitors and rare breeding residents." At this point, birds from other continents start dominating the list.