Sixty-third Supplement to the AOS Check-list of North American Birds Publishes Today in Ornithology

The Sixty-third Supplement to the Check-list of North American Birds, a publication of the American Ornithological Society (AOS), is published today in the journal Ornithology and includes numerous updates to the classification of North American bird species. A few highlights from this year’s supplement, detailed below, include species splits in meadowlarks, kites, and several hummingbird species, among others; the addition of a giant-petrel; and a reclassification of the extinct Labrador Duck. 

Every summer, ornithologists, government agencies, NGOs, conservationists, and bird lovers who regularly consult the Check-list eagerly anticipate the annual update by the AOS’s North American Classification Committee (NACC), the official authority on the names and classification of the region’s birds. The Check-list was first published in 1886. 

The full Check-list Supplement is available at: 

Species Splits

Eastern Meadowlark Split

It’s time to add a new species of meadowlark to your checklist. The NACC revisited a proposed split in meadowlarks that was last considered in 2016. This year, Johanna K. Beam, now a Ph.D. student at Pennsylvania State University, based her proposal (Proposal 2022-C-2) to split Chihuahuan Meadowlark (Sturnella lilianae) from Eastern Meadowlark (Sturnella magna) on new evidence from her undergraduate research at the University of Colorado. She employed a quantitative vocal analysis and whole genome sequencing for individuals of Western Meadowlark (Sturnella neglecta), Eastern Meadowlark, and the populations that are being split into Chihuahuan Meadowlark. “The genetic data show that Eastern Meadowlark and this new meadowlark, which were previously lumped as the same species, are actually not each other’s closest relatives,” NACC chair Terry Chesser of the U.S. Geological Survey explains, adding, “Eastern and Western Meadowlarks are more closely related to each other than to the newly split Chihuahuan Meadowlarks.” Additionally, the quantitative vocal analysis in Beam’s new study showed differences between vocalizations of Eastern and Chihuahuan meadowlarks. Both the genetic and vocal analyses indicated that the Chihuahuan Meadowlark includes two subspecies: lilianae, whose breeding grounds are primarily in Arizona, New Mexico, and northern Mexico, and auropectoralis, which occurs further south in western Mexico. 

Caribbean Bird Splits

Several species of Caribbean and Neotropical birds are newly recognized in this latest Supplement, including species of hummingbirds and kites. Oscar Johnson (University of Texas, El Paso), a member of the Committee’s Early Career Systematics Group, and Committee member Blanca E. Hernández (Universidad Nacional Autónoma de México) presented convincing evidence (Proposal 2022-C-4) that the species formerly known as the Antillean Mango (Anthracothorax dominicus) should be separated into two species, the Puerto Rican Mango (A. aurulentus) and the Hispaniolan Mango (A. dominicus), based on differences in plumage similar in degree to those between other recognized species of mango.

On Jamaica, what were previously considered to be two subspecies of the endemic Streamertail (Trochilus polytmus), are being elevated to species status: the Red-billed Streamertail (T. polytmus) and Black-billed Streamertail (T. scitulus). Committee member Shawn Billerman (Cornell University) proposed (Proposal 2022-A-19) that the streamertails on Jamaica be split into separate species due to the narrow and stable hybrid zone between them, indicating strong selection against hybrids, and sharp turnover in bill color and some genetic characters, despite low levels of genetic divergence overall. These birds “have an incredibly narrow hybrid zone in eastern Jamaica,” Chesser explains, and, as Billerman states in his proposal, “they do not form a freely and randomly breeding population.” The Red-billed Streamertail is widespread across most of Jamaica, whereas the Black-billed Streamertail is found only on the eastern end of the island. 

Due primarily to its distinct morphology, the Cuban Kite (Chondrohierax wilsonii) is being split from the Hook-billed Kite (C. uncinatus), a raptor found from central Mexico to Argentina, thanks to a persuasive proposal by Oscar Johnson (Proposal 2022-B-4). These morphological differences include bill and plumage coloration. “The Hook-billed Kite, throughout its whole range from the southern U.S. and far into the Neotropics, tends to be pretty uniform, whereas the Cuban Kite, based on available museum specimens, is quite distinct morphologically,” Chesser says.

Additions & Deletions

Northern Giant-Petrel Added to Main List

A proposal from Committee member Jon L. Dunn (Proposal 2022-C-8) resulted in the Northern Giant-Petrel (Macronectes halli) being added  to the Main List. In an exciting sighting by a fisherman in 2019, a Northern Giant-Petrel was spotted and photographed off the coast of Ocean Park, Washington (U.S.). “We added Northern Giant-Petrel to the Checklist — it’s typically a bird of the Southern oceans, so it’s pretty spectacular to find it that far north, off Washington state,” remarks Chesser. Previous records of giant-petrel (the Northern Giant-Petrel and Southern Giant-Petrel were long considered the same species) in the Check-list area were poorly substantiated and have long been discounted; the account for Southern Giant-Petrel in the Appendix, based on these old records, has now been deleted. 

New Classification

Changing the Classification of the Labrador Duck

Based on a proposal from Shawn Billerman (Proposal C-18-A), the Committee voted to change the taxonomic placement of the Labrador Duck (Camptorhynchus labradorius), an extinct sea duck last reported in 1875. According to a phylogenetic analysis of mitochondrial genomes, the nearest relative of the Labrador Duck is the Steller’s Eider (Polysticta stelleri). “The Labrador Duck is more closely related to the eiders than it is to the scoters, which is where it had previously been placed,” states Chesser.

Other Changes

Additional changes introduced in this year’s Check-list Supplement include the split of the Broad-billed Hummingbird (Cynanthus latirostris) into three species, two of which are endemic to Mexico; the lump of the Long-tailed Sabrewing (Pampa excellens) with the Wedge-tailed Sabrewing (P. curvipennis); and others.

About the Journal
Ornithology (formerly, The Auk: Ornithological Advances) is a peer-reviewed, international journal of ornithology published by the American Ornithological Society. The journal’s name changed to Ornithology in January of 2021. Ornithology commenced publication in 1884 and in 2009 was honored as one of the 100 most influential journals of biology and medicine over the past 100 years.


  1. Thank you for the Supplement each year. Much appreciated, and grateful.
    And I am curious if there are plans afoot for a new book to incorporate and synthesize the many annual Supplements together.
    If I am not mistaken, the last “classification book” of North Amerian birds was circa 1998?

Leave a Reply

Your email address will not be published. Required fields are marked *