2021 eBird Taxonomy Update

By Graham Sorenson and Denis Lepage, Birds Canada August 18, 2021
Short-billed Gull Larus brachyrhynchus


eBird data are currently being updated as a part of eBird’s 2021 Taxonomy Update. It is normal to see life list numbers change this week and to see some names displaying inconsistently as the changes are applied. If you see any unexpected behaviors in eBird, please check again after 20 August and write to us if you’re still seeing something unexpected after that date.

If you use eBird Mobile, make sure you go to the App Store or Google Play Store and update to the latest version. This’ll make sure you have the new taxonomy and the most up-to-date lists for reporting.

What’s happening?

Every day, new and fascinating discoveries are made by birders and ornithologists alike. Technological advances are helping us learn more about bird species around the world, from eBird reports of a species outside its known range to more complete understandings of genetic relationships among bird species. This month, we’re going through your more than 1,053,114,868 eBird observations and updating them to the most current ornithological knowledge. Taxonomy Day (as we like to call it at eBird) is a time to reflect on all that we have learned about birds throughout our lifetimes—and how much there still is to learn!

This year’s taxonomy update (v2021) includes 17 newly-described species, an increase of 94 new species from ‘splits’ of one species into two or more different species, and 8 ‘lumps’—birds that were formerly considered to be multiple species, but now are considered to be a single species. This results in an increase of 103 species to a global total of 10,824 species. In Canada, a lump and a split will result in no net changes to Canada’s species totals. There are also many changes to scientific names and taxonomic ordering of species based on their evolutionary relationships. Recognizing a species isn’t just about changing the name or adding a new lifer; full species status can have significant impacts for conservation or research as well.

Many times new species emerge after years of detective work, examining museum specimens, genetic data, and audio recordings. Other times well-known subspecies are separated after stronger data showing physical, genetic, and/or vocal differences become available. Your observations can be the spark that inspires ornithologists to examine taxonomic relationships among species. Maybe your media played a part in helping separate or lump species this year? Thank you for your eBird checklists and media contributions to the Macaulay Library—you help make this possible!

What do you need to do?

For the most part, you can sit back, keep eBirding, and check out your lists after the update is complete. This complex process may require a couple weeks before it is fully complete. We update all of your records automatically, so you don’t have to do anything to have your lists reflect the latest taxonomy. The best thing you can do is read on to learn more about the changes.

2021 eBird Taxonomy Changes Impacting Canada

Most taxonomic changes do not impact species found in Canada, but below we highlight the few splits, lumps, and name changes that will be noticed by Canadian eBirders. To look at a full comparison of the changes from the 2019 taxonomy, explore the Avibase compare tool.


Mew Gull Larus canus is split into:

Birders who enjoy challenging gull ID can now try to find Common Gull (typically found in East Asia and Europe) in North America and Short-billed Gull (the North American species) in other regions. Check ‘Mew Gulls’ in the Eastern US and Canada with care, as both species may occur in that area. If you have seen Mew Gull in Western Canada (BC, AB, SK, MB, YT and NT), these will automatically be changed to Short-billed Gull. If you have seen Mew Gull in Eastern Canada (ON, QC, NB, NS, PE, NL and NU) and did not specify subspecies when reporting them, they will now show as Common/Short-billed Gull. Either species can be observed in the East, and they can be difficult to separate, but this article provides some good identification tips.


Sedge Wren Cistothorus platensis is split into:

This split recognizes the distinctive song, plumage, and migratory behavior of each species. The migratory Sedge Wren breeds in central-northern North America and winters in the southern US; it sings a fairly uniform song, while the non-migratory Grass Wren occurs from Mexico to South America and sings a more complex song. The two species co-occur only in Mexico in the northeastern state of Veracruz (though at opposite ends of the state, not at a single site). If you have seen Sedge Wren in Canada/US and in Central/South America, this is a new species for you.


Northwestern Crow Corvus caurinus is lumped with American Crow Corvus brachyrhynchos [map] [media] [my records].

Restricted to the Pacific Northwest of the United States, the Pacific Coast of Canada, and southeastern Alaska, Northwestern Crow has always been a controversial entity, especially at the southern margins of its range where it is believed to hybridize extensively with American Crow. New genetic data (from this paper) highlight the extent of that hybridization, suggesting that Northwestern Crow does not warrant species status and should be lumped with the widespread American Crow. For anyone that has seen crows in coastal British Columbia, these are now considered American Crows and are a loss of a life list species.


Common and Scientific Name Changes:

Thick-billed Longspur will replace McCown’s Longspur as the common name for Rhynchophanes mccownii. The French name for the species will now be Plectrophane à ventre gris.

Ruby-crowned Kinglet has a scientific name change to Corthylio calendula, putting it in its own genus separate from Golden-crowned Kinglet (Regulus satrapa).

New genera for most cormorant species found in Canada: genus change from Phalacrocorax to Urile for Brandt’s and Pelagic cormorant, genus change from Phalacrocorax to Nannopterum for Double-crested and Neotropic cormorants, and no change to Great Cormorant (Phalacrocorax carbo).

Spruce Grouse is changing genera from Falcipennis canadensis to Canachites canadensis.


Splits and Lumps of Potential Interest to Canadian Birders:

Vaux’s Swift has a subspecies split, but the common and scientific names for the parent species remain the same. Ashy-tailed Swift (Chaetura Andrei) is split into a new Venezuelan endemic.

Barred Owl has the same situation as Vaux’s Swift, with Cinereous Owl (Strix sartorii) being split from Barred Owl into a rare endemic to Mexico.

Crested and Southern caracara will be lumped, resulting in a scientific name change for Crested Caracara, now Caracara plancus.  The French name for the species now reverts to Caracara huppé, instead of Caracara du Nord.


To read further about global changes made in the 2021 eBird Taxonomy update, please explore this article on eBird.org or read the full report from eBird here.