Changes to North America’s bird list in 2021

This year’s supplement to the official Check-list of North American Birds makes several changes at the genus level — for grouse, kinglets, cormorants, and other species. It also splits a few species from related birds found outside Canada and the United States. And it rearranges the sequence of 69 families of the continent’s passerines (songbirds).

Last month, I posted a summary of the potential changes that we’d get this year. Below is a roundup of the decisions announced today by the American Ornithological Society’s Committee on Classification and Nomenclature of North and Middle American Birds.

Hello, Short-billed Gull

The birds previously known as Mew Gull have been separated into two species: Short-billed Gull of North America and Common Gull of Asia and Europe. The committee based the split “largely on differences in display vocalizations,” and it noted “the species also show genetic and morphological differences and had been treated as conspecific [the same species] based on weak evidence.”

Short-billed Gulls breed in Alaska and western Canada and winter mostly along the Pacific coast.

More splits and lumps

Cape Verde Storm-Petrel (Hydrobates jabejabe), a small seabird that lives year-round at the Cape Verde Islands of the eastern Atlantic Ocean, has been split from Band-rumped Storm-Petrel (H. castro), which is found in the Gulf of Mexico and the western Atlantic.

Crested Caracara of North America and northern South America is being lumped with Southern Caracara, which is found in most of South America. The lumped species will be known as Crested Caracara (Caracara plancus). The two had been split only two decades ago but are considered one species again in part because of extensive hybridization in the Amazon region. 

Sedge Wren is now split from its nonmigratory relative, Grass Wren. Sedge Wren breeds in the Great Plains and Great Lakes region and winters mainly in the southeastern U.S. Grass Wren is found from Mexico south to Chile, Argentina, and the Falkland Islands.

Barred Owl is being split from Cinereous Owl, which is found in a handful of locations in Mexico. The split is based on differences in voice, mitochondrial DNA, habitat, and plumage.

Bahama Nuthatch is being spilt from Brown-headed Nuthatch. After Hurricane Dorian in 2019, the Bahama birds may be extinct.

West Mexican Euphonia is being split from Scrub Euphonia. The new Mexican endemic species is found on the country’s Pacific slope. Scrub Euphonia is found from southern Mexico to Costa Rica.

St. Kitts Bullfinch is being recognized as a species distinct from Puerto Rican Bullfinch. Sadly, the St. Kitts bird hasn’t been seen since 1929 and is listed as extinct.

New genera

Spruce Grouse is being returned to the genus Canachites.

Five of North America’s cormorants are moving genera. Great Cormorant remains in the genus Phalacrocorax. Brandt’s, Red-faced, and Pelagic are moving to the genus Urile, and Double-crested and Neotropic are moving to Nannopterum.

Ruby-crowned Kinglet is moving to its own genus: Corthylio. The change distinguishes the species from Golden-crowned Kinglet, which remains in Regulus.

Five-striped Sparrow, a bird of Mexico and southeastern Arizona, moves to Amphispizopsis and out of the genus Amphispiza, which it shared with Black-throated Sparrow.

Java Sparrow, an Asian species that is established in Hawai’i, is now in the genus Padda.

Lavender Waxbill, a finch of central Africa that is found in Hawai’i, is moving to Glaucestrilda.

Rejections

The committee considered but rejected splits to Magnificent Frigatebird, Swainson’s Thrush, and Rufous-backed Robin. And it said no to a proposal to lump McKay’s Bunting and Snow Bunting.

For more information on the changes to the check-list, you can download a PDF of the announced changes from Oxford University Press or see this post from the American Birding Association.