For serious birders in North America, it’s become a July tradition to wait for the annual supplement from the AOU Checklist Committee.
For everyone else, the geeky statement above needs some explanation. The American Ornithologists’ Union (AOU) Checklist of North American Birds was first published in 1886. For the last 130 years and through seven editions, it’s served as the official authority on classification and names of all bird species on this continent. That redbird you’re seeing in the backyard is officially called the Northern Cardinal (scientific name: Cardinalis cardinalis) and it’s classified in the family Cardinalidae. Why? Because the AOU Checklist says so. When it comes to communicating about birds, it’s incredibly helpful to have one standardized list of labels.
Yet names do change sometimes—and so do entire species. Half a century ago, that red bird was just called a “Cardinal”; its scientific name was Richmondena cardinalis, and it was classified in the family Fringillidae. The changes reflect how our understanding of birds and their relationships is always improving. The AOU Checklist Committee (technically the Committee on Classification and Nomenclature—North and Middle America) receives formal proposals based on published research, which they then consider and approve only if the evidence is compelling enough.
The most recent edition of the AOU Checklist was published in 1998. In the time since, the committee has issued numerous updates to keep up with the amount of research that’d been released. Since 2002, these supplements have been published annually in the July issue of The Auk, the journal of the American Ornithologists’ Union.