If you keep your lists in eBird, it’s possible that some of them just changed. The folks at the Cornell Lab of Ornithology are currently updating their database to reflect changes to the eBird/Clements taxonomy. Splits of Yellow Warbler, Whimbrel, and Fea’s Petrel are of most consequence to birders in North America, and you will see them explained below. For further details about these changes and to see changes from further afield, click here.
This eBird/Clements taxonomy update results in another difference with the North American Checklist of the American Ornithological Society. Other differences between the AOS and eBird/Clements checklists, such as they were then, are summarized toward the end of 2024 ABA Checklist report (Pyle 2024). Nowadays, it can be assumed that any change in taxonomy is due at least partly to analysis of new genetic data, so that is not always mentioned here. Species marked with a single asterisk (*) below are those which are not known to occur in the ABA Area but are known to occur elsewhere in North America. Those which are not known from North America are marked with double asterisks (**).
Split of Yellow Warbler
Mangrove Yellow Warbler (Setophaga petechia)
Northern Yellow Warbler (Setophaga aestiva)
This split treats the migratory populations as Northern Yellow Warbler, whose adult males lack rust on the crown, and the two “classic” nonmigratory Neotropical populations, “Golden” and “Mangrove”, as Mangrove Yellow Warbler (sensu lato). Northern Yellow Warbler is quite widespread as a breeder across the mainland ABA Area, whereas Mangrove Yellow Warbler is restricted to coastal mangrove-lined islands and inlets of southern Florida (“Golden”) and southern Texas (“Mangrove” sensu stricto). There also exist vagrant regards of Mangrove Yellow Warbler from California (2), Arizona (1), and Louisiana (1) (eBird 2025).
Adult males of the “Golden” group, which is mostly Caribbean in distribution, tend to have a rusty crown patch, whereas adult males of the “Mangrove” group (sensu stricto), which is mostly mainland in distribution, have wholly rusty heads. These plumage distinctions don’t hold up, though, across all populations within each group, which is in part why they are treated together as a single species in this new taxonomy. (Of course, these days, genetic data usually constitute the main reason for a split.)
Compared to Northern, Mangrove has shorter wings and a slightly thinner, more decurved bill. Adult males are slightly darker and greener above (Sibley 2014). This is especially noticeable on the crown of “Golden” Mangrove Yellow Warblers. Female Mangroves average duller and greener than Northerns, and many immature Mangroves appear strikingly different; they are mostly gray with faint greenish tones and very little in the way of yellow. “Subadult” male Mangroves have variable amounts of rust on the head where the local males are thus colored. This makes Mangrove Yellow Warbler one of the few New World warblers with obviously prolonged, field-notable plumage maturation (e.g., American Redstart).
The two species also differ vocally. Compared to Northern, the vocalizations of Mangrove average richer, lower, and more penetrating—sometimes appreciably so (Retter at al. 2025).
Split of Whimbrel
Eurasian Whimbrel (Numenius phaeopus)
Hudsonian Whimbrel (Numenius hudsonicus)
The dark-rumped Hudsonian Whimbrel is the species expected in the Americas, whereas the white-rumped Eurasian Whimbrel is the species expected in the Old World. However, both species are known to hop oceans and appear as vagrants in the wrong hemisphere, so be on the lookout for Eurasian Whimbrels in North America! Eurasian is regular in the Bering Sea region, rare in Atlantic Canada and the northeastern U.S., and casual in the Hawaiian Islands, where Hudsonian is of more frequent occurrence (Floyd 2025). Records also exist in the “east” for Texas, Ohio, Michigan, Ontario, Québec, Bermuda, Cuba, and the Lesser Antilles; and in the “west” for the Yukon Territory, Washington, and California.
Note that the American Ornithological Society’s North American Checklist Committee (AOS-NACC) recently voted against splitting this species, making it another taxonomical difference between the two checklists.
Split of Fea’s Petrel
Cape Verde Petrel (Pterodroma feae)**?
Desertas Petrel (Pterodroma deserta)
These two species are nearly identical, and, indeed, Howell (2012) includes them in the same account “because it is unclear how they can be distinguished at sea except perhaps by molt timing”. Thus, it seems uncertain whether there are any verifiable photographic records of Cape Verde Petrel from North American waters. However Howell (2012) does include a photo of a bird, molting inner primaries in late May, that may be that species.
Split of Striated Heron
Striated Heron (Butorides striata)*
Lava Heron (Butorides sundevalii)**
Little Heron (Butorides atricapilla)**
This split doesn’t affect us here in North America, but if you’ve been to the Galápagos Islands or the Old World, you may have added a species to your life list.
——-
In accordance with actions taken by AOS-NACC in July 2025, this eBird/Clements update splits Warbling Vireo and Squirrel Cuckoo. See this year’s Checklist Redux for details.
References
eBird. 2025. An online database of bird distribution and abundance. Cornell Lab of Ornithology. ebird.org. Accessed 29 Oct 2025.
Floyd, Ted. 2025. National Geographic Field Guide of the United States and Canada, Eighth Edition. National Geographic.
Howell, Steve N. G. 2012. Petrels, Albatrosses, and Storm-Petrels of North America.
Pyle, Peter, Luke DeCicco, Douglas Gochfeld, Lauren Harter, Matt Heindel, Alvaro Jaramillo, Andrew W. Kratter, Marky Mutchler, and David Sibley. 2024. 35th Report of the ABA Checklist Committee. North American Birds. 75(2): 36–45.
Retter, Michael L. P., Luke Seitz, and Eric Antonio Martínez. A Photographic Guide to the Birds of Mexico, Guatemala, and Belize. Unpublished manuscript, referenced Oct 2025.
Sibley, David Allen. 2014. The Sibley Guide to Birds, Second Edition.
Recommended Citation: Retter, Michael L. P. 2025. The 2025 eBird/Clements Update. North American Birds. 77(1).
If you keep your lists in eBird, it’s possible that some of them just changed. The folks at the Cornell Lab of Ornithology are currently updating their database to reflect changes to the eBird/Clements taxonomy. Splits of Yellow Warbler, Whimbrel, and Fea’s Petrel are of most consequence to birders in North America, and you will see them explained below. For further details about these changes and to see changes from further afield, click here.
This eBird/Clements taxonomy update results in another difference with the North American Checklist of the American Ornithological Society. Other differences between the AOS and eBird/Clements checklists, such as they were then, are summarized toward the end of 2024 ABA Checklist report (Pyle 2024). Nowadays, it can be assumed that any change in taxonomy is due at least partly to analysis of new genetic data, so that is not always mentioned here. Species marked with a single asterisk (*) below are those which are not known to occur in the ABA Area but are known to occur elsewhere in North America. Those which are not known from North America are marked with double asterisks (**).
Split of Yellow Warbler
Mangrove Yellow Warbler (Setophaga petechia)
Northern Yellow Warbler (Setophaga aestiva)
This split treats the migratory populations as Northern Yellow Warbler, whose adult males lack rust on the crown, and the two “classic” nonmigratory Neotropical populations, “Golden” and “Mangrove”, as Mangrove Yellow Warbler (sensu lato). Northern Yellow Warbler is quite widespread as a breeder across the mainland ABA Area, whereas Mangrove Yellow Warbler is restricted to coastal mangrove-lined islands and inlets of southern Florida (“Golden”) and southern Texas (“Mangrove” sensu stricto). There also exist vagrant regards of Mangrove Yellow Warbler from California (2), Arizona (1), and Louisiana (1) (eBird 2025).
Adult males of the “Golden” group, which is mostly Caribbean in distribution, tend to have a rusty crown patch, whereas adult males of the “Mangrove” group (sensu stricto), which is mostly mainland in distribution, have wholly rusty heads. These plumage distinctions don’t hold up, though, across all populations within each group, which is in part why they are treated together as a single species in this new taxonomy. (Of course, these days, genetic data usually constitute the main reason for a split.)
Compared to Northern, Mangrove has shorter wings and a slightly thinner, more decurved bill. Adult males are slightly darker and greener above (Sibley 2014). This is especially noticeable on the crown of “Golden” Mangrove Yellow Warblers. Female Mangroves average duller and greener than Northerns, and many immature Mangroves appear strikingly different; they are mostly gray with faint greenish tones and very little in the way of yellow. “Subadult” male Mangroves have variable amounts of rust on the head where the local males are thus colored. This makes Mangrove Yellow Warbler one of the few New World warblers with obviously prolonged, field-notable plumage maturation (e.g., American Redstart).
The two species also differ vocally. Compared to Northern, the vocalizations of Mangrove average richer, lower, and more penetrating—sometimes appreciably so (Retter at al. 2025).
Split of Whimbrel
Eurasian Whimbrel (Numenius phaeopus)
Hudsonian Whimbrel (Numenius hudsonicus)
The dark-rumped Hudsonian Whimbrel is the species expected in the Americas, whereas the white-rumped Eurasian Whimbrel is the species expected in the Old World. However, both species are known to hop oceans and appear as vagrants in the wrong hemisphere, so be on the lookout for Eurasian Whimbrels in North America! Eurasian is regular in the Bering Sea region, rare in Atlantic Canada and the northeastern U.S., and casual in the Hawaiian Islands, where Hudsonian is of more frequent occurrence (Floyd 2025). Records also exist in the “east” for Texas, Ohio, Michigan, Ontario, Québec, Bermuda, Cuba, and the Lesser Antilles; and in the “west” for the Yukon Territory, Washington, and California.
Note that the American Ornithological Society’s North American Checklist Committee (AOS-NACC) recently voted against splitting this species, making it another taxonomical difference between the two checklists.
Split of Fea’s Petrel
Cape Verde Petrel (Pterodroma feae)**?
Desertas Petrel (Pterodroma deserta)
These two species are nearly identical, and, indeed, Howell (2012) includes them in the same account “because it is unclear how they can be distinguished at sea except perhaps by molt timing”. Thus, it seems uncertain whether there are any verifiable photographic records of Cape Verde Petrel from North American waters. However Howell (2012) does include a photo of a bird, molting inner primaries in late May, that may be that species.
Split of Striated Heron
Striated Heron (Butorides striata)
Lava Heron (Butorides sundevalii)**
Little Heron (Butorides atricapilla)**
This split doesn’t affect us here in North America, but if you’ve been to the Galápagos Islands or the Old World, you may have added a species to your life list.
——-
In accordance with actions taken by AOS-NACC in July 2025, this eBird/Clements update splits Warbling Vireo and Squirrel Cuckoo. See this year’s Checklist Redux for details.
References
eBird. 2025. An online database of bird distribution and abundance. Cornell Lab of Ornithology. ebird.org. Accessed 29 Oct 2025.
Floyd, Ted. 2025. National Geographic Field Guide of the United States and Canada, Eighth Edition. National Geographic.
Howell, Steve N. G. 2012. Petrels, Albatrosses, and Storm-Petrels of North America.
Pyle, Peter, Luke DeCicco, Douglas Gochfeld, Lauren Harter, Matt Heindel, Alvaro Jaramillo, Andrew W. Kratter, Marky Mutchler, and David Sibley. 2024. 35th Report of the ABA Checklist Committee. North American Birds. 75(2): 36–45.
Retter, Michael L. P., Luke Seitz, and Eric Antonio Martínez. A Photographic Guide to the Birds of Mexico, Guatemala, and Belize. Unpublished manuscript, referenced Oct 2025.
Sibley, David Allen. 2014. The Sibley Guide to Birds, Second Edition.
Recommended Citation: Retter, Michael L. P. 2025. The 2025 eBird/Clements Update. North American Birds. 77(1).
