Puntarenas

As you may have heard or noticed while eBirding recently, the eBird/Clements annual taxonomy update is in the process of being implemented. In this article, we will summarize the changes that affect Central America. For a global perspective, please see this article from Team eBird.

We would also like to highlight that currently, until 28 October 2024, all species accounts in Birds of the World are freely accessible, including every species affected by the taxonomy split. Birds of the World offers comprehensive life history information on each of the world’s 11,145 bird species, and is now bilingual, with all content available in English and Spanish. Check it out!

In a nutshell, the main taxonomy changes affecting the region are the following:

Old name in Central America	New name in Central America
Herring Gull (Larus argentatus)	American Herring Gull (Larus smithsonianus)
Cory’s Shearwater (Calonectris diomedea)	Cory’s Shearwater (Calonectris borealis) and Scopoli’s Shearwater (Calonectris diomedea)
Brown Booby (Sula leucogaster)	Brown Booby (Sula leucogaster) and Cocos Booby (Sula brewsteri)
Barn Owl (Tyto alba)	American Barn Owl (Tyto furcata)
Cooper’s Hawk (Accipiter cooperii)	Cooper’s Hawk (Astur cooperii)
Bicolored Hawk (Accipiter bicolor)	Bicolored Hawk (Astur bicolor)
House Wren (Troglodytes aedon)	Southern House Wren (Troglodytes musculus)
Rufous-naped Wren (Campylorhynchus rufinucha)	Rufous-backed Wren (Campylorhynchus capistratus)
Northern Flicker (Colaptes auratus)	Guatemalan Flicker (Colaptes mexicanoides)
Crested Bobwhite (Colinus cristatus)	Spot-bellied Bobwhite (Colinus leucopogon) and Crested Bobwhite (Colinus cristatus)
Long-tailed Woodcreeper (Deconychura longicauda)	Piping Woodcreeper (Deconychura typica)
Plain Xenops (Xenops minuta)	Northern Plain-Xenops (Xenops mexicanus)
Red-throated Ant-Tanager (Habia fuscicauda)	Red-throated Ant-Tanager (Driophlox fuscicauda)
Black-cheeked Ant-Tanager (Habia atrimaxillaris)	Black-cheeked Ant-Tanager (Driophlox atrimaxillaris)
White-throated Magpie-Jay (Calocitta formosa)	White-throated Magpie-Jay (Cyanocorax formosus)
Brown Jay (Psilorhinus morio)	Brown Jay (Cyanocorax morio)
Spot-tailed Nightjar (Hydropsalis maculicaudus)	Spot-tailed Nightjar (Antiurus maculicaudus)
Mangrove Hummingbird (Amazilia boucardi)	Mangrove Hummingbird (Chrysuronia boucardi)
Yellow-breasted Crake (Hapalocrex flaviventer)	Yellow-breasted Crake (Laterallus flaviventer)
Least Bittern (Ixobrychus exilis)	Least Bittern (Botaurus exilis)
Western Cattle Egret (Bubulcus ibis)	Western Cattle Egret (Ardea ibis)
Slaty-winged Foliage-gleaner (Phylidor fuscipenne)	Slaty-winged Foliage-gleaner (Neophylidor fuscipenne)
White-fronted Tyrannulet (Phyllomyias zeledoni)	White-fronted Tyrannulet (Acrochordopus zeledoni)
Rough-legged Tyrannulet (Phyllomyias burmeisteri)	Rough-legged Tyrannulet (Acrochordopus burmeisteri)

Please read on for a bit more information on some of these taxonomic changes.

Herring Gull split

As many gull aficionados already knew or suspected, Herring Gull (Larus argentatus) is really four species. Thus, the taxon that occurs in Central America is now called American Herring Gull (Larus smithsonianus). The other three do not normally occur in Central America, although European Herring Gull (Larus argentatus) could occur as a vagrant.

• American Herring Gull Larus smithsonianus [map] [media] [my records]
  • • RANGE: northern North America (Alaska to Atlantic coast); winters to Central America

Cory’s Shearwater split

Seabird experts have long been expecting the split of Cory’s Shearwater Calonectris diomedea into Cory’s Shearwater Calonectris borealis from Scopoli’s Shearwater Calonectris diomedea and it has finally arrived. The fact that these birds can tell each other apart (probably using smell more than we might expect) doesn’t mean that our birding lives will be better or easier–these are VERY hard to identify in the field! Also, make sure you pay attention to the tricky name change: the English name stays the same on one and the scientific name switches and the reverse happens for Scopoli’s.

The main thing to know about these two is that Scopoli’s breeds primarily in the Mediterranean Sea and then disperses out from there, while Cory’s breeds primarily on Atlantic islands (e.g., Azores, Canary Islands) and disperses widely from there. While Cory’s Shearwater is more likely in Central America, both are possible and thus both will need thorough documentation when reported in the region.

• Cory’s Shearwater Calonectris borealis [map] [media] [my records]
  • • RANGE: eastern Atlantic, breeding from Azores southward to Canary Islands and eastward to Galicia (northwestern Spain) and Berlengas Islands (off west-central Portugal); outside breeding season ranges widely in Atlantic, but mainly in upwelling systems of the Benguela and Agulhas currents
• Scopoli’s Shearwater Calonectris diomedea [map] [media] [my records]
  • • RANGE: breeds Mediterranean islands, outside breeding season moving to winter mainly in upwelling systems of tropical eastern Atlantic

For detailed field ID, be sure to refer to Flood and Gutiérrez (2021), which give detailed information on the range of variation in both species and stress that while entirely dark underprimaries can be a safe field mark for Cory’s, safe identification of Scopoli’s requires a tenth primary (p10) that shows 20% or more white (as measured from the white underprimary coverts). Other traits like structure (Scopoli’s is more delicately built on average), extent of dark on the underwing coverts, and presence of one or two spots on the underprimary coverts can be supportive, but that the extent of whitish on the tenth primary is by far the most important field mark. Extent of white on the ninth, eighth, and other primaries seems to have extensive overlap so should not be used as a field mark.

Even after reading and re-reading (and re-reading) Flood and Guitiérrez though, you should expect to have a lot of birds “get away” unidentified, either because of distance or because, even with excellent looks and point blank photos, they were intermediate or showed inconsistent field marks. Please use the slash option below liberally (and remember, we are treating almost all eBird records as slashes unless the user has specified the finer-scale ID themselves.

• Cory’s/Scopoli’s Shearwater Calonectris borealis/diomedea [map] [media] [my records]

and, since other species are always a concern for distant shearwaters, these slashes also exist:

• Cory’s/Scopoli’s/Cape Verde Shearwater Calonectris borealis/diomedea/edwardsii [map] [media] [my records]
• Cory’s/Scopoli’s/Great Shearwater Calonectris borealis/diomedea/Ardenna gravis [map] [media] [my records]

Brown Booby split

Cocos Booby (Sula brewsteri) is split from Brown Booby (S. leucogaster). Cocos Booby occurs mostly on the Pacific coast from northern South America to southern California, and increasingly in Hawaii and more widely in the Pacific. Brown Booby includes all Atlantic and Indian Ocean populations (S. l. leucogaster), plus subspecies plotus of the Indian and tropical Pacific Oceans.

Both species come into contact in the Hawaiian Islands, and the lack of hybridization there was a major reason for the split. “True” Brown Booby has yet to be found near the Pacific coast, but will be one to watch for, since all taxa in this group seem to be expanding their ranges as the oceans warm.

• Brown Booby Sula leucogaster [map] [media] [my records]
  • Brown Booby (Atlantic) Sula leucogaster leucogaster[map] [media]
    • RANGE: islands in Gulf of Mexico, Caribbean, and tropical Atlantic
  • Brown Booby (Forster’s) Sula leucogaster plotus[map] [media]
    • RANGE: breeds on islands in the Red Sea, tropical Indian Ocean, and tropical western and central Pacific Ocean
• Cocos Booby Sula brewsteri [map] [media] [my records]
  • Cocos Booby (Brewster’s) Sula brewsteri brewsteri [map] [media] 
    • RANGE: islands in Gulf of California and off western Mexico
  • Cocos Booby (Colombian) Sula brewsteri etesiaca [map] [media] 
    • RANGE: Pacific islands off Central America and Colombia

The identification of these two species is extremely challenging and just being worked out. See VanderWerf (VanderWerf, E. A. 2018. Geographic variation in the Brown Booby: Field identification of males and females by subspecies. Birding 50 (5): 48–54) for the best treatment on separation of adults; key field marks are shown below:

• adult male brewsteri (and to a lesser extent, etesiaca) are highly distinctive with variable amounts of frosty white coloration on the head, neck, nape, and forehead; any pale coloration in this area on birds of any age distinguishes Cocos Booby from both subspecies of Brown Booby, which always has a dark brown head
• female brewsteri and estesiaca can be quite dark headed, so focus on other field marks:
  • compared to plotus, a yellow-based bill that is pinkish from the midpoint to the tip should indicate Cocos; plotus is always yellow with a faint green cast
  • plotus averages a smaller dark spot in front of the eye compared to brewsteri
• On all ages, brewsteri averages more dark in the underwing coverts, usually showing a line of dark partially bisecting the white of the underwing
• brewsteri has a slimmer bill
• Not mentioned in the article, but maybe worth watching: it seems that plotus consistently shows a narrow band of bar skin behind the eye, while in brewsteri (and etesiaca?) the pale orbital ring touches dark feathering at the rear of the eye. In preliminary assessments, this field mark seems to hold on young birds as well as adults.

Even with the above identification tips though, a large number of distant or tricky birds will evade identification. Please use the slash liberally when needed!

• Brown/Cocos Booby Sula leucogaster/brewsteri [map] [media] [my records]

Barn Owl split

Barn Owl (Tyto alba) is split into three species, generally separated at the continental level: American Barn Owl Tyto furcata, of North and South America; Western Barn Owl Tyto alba of Europe, Africa, and the Middle East (east to central Iran); and Eastern Barn Owl Tyto javanica which occurs Pakistan, India, and Sri Lanka east through Southeast Asia, Indonesia, and Australasia. These owls generally look similar, but some subtle differences in coloration and pattern may be apparent, although each has multiple subspecies which also vary intraspecifically. Genetic differences were one of the main reasons for the split, but are supported by vocal differences, especially the unique clicking vocalization made by American Barn Owl which appears not to be present in other Barn Owl taxa.

• American Barn Owl Tyto furcata [map] [media] [my records]
  

Worldwide genus Accipiter split into 5 genera

The genus Accipiter is split into 5 genera, but no species are split. This means that two Central American raptors previously considered members of Accipiter will now have a different genus name, while two others will remain in Accipiter. For Central America, this has the following implications:

Cooper’s Hawk (Accipiter cooperii) now becomes Cooper’s Hawk (Astur cooperii).

Bicolored Hawk (Accipiter bicolor) now becomes Bicolored Hawk (Astur bicolor).

Sharp-shinned Hawk (Accipiter striatus) remains Accipter striatus. This includes forms grouped under Accipiter striatus such as chionogaster (White-breasted). No change for this species. The marginal Gray-bellied Hawk (Accipiter poliogaster) remains Gray-bellied Hawk (Accipiter poliogaster). (Note that Tiny Hawk used to be grouped in Accipiter as well, but this was assigned its own genus last year: Microspizias.)

House Wren split

The House Wren (Troglodytes aedon) is split into 7 species; 2 species are widespread, while the remaining 5 species are island endemics. Northern House Wren (Troglodytes aedon) occurs in North America and Mexico south to the Isthmus of Tehuantepec, while Southern House Wren (Troglodytes musculus) occurs in Mexico, Central America, and South America. So in Central America, House Wren (Troglodytes aedon) becomes Southern House Wren (Troglodytes musculus).

• Southern House Wren Troglodytes musculus [map] [media] [my records]

Rufous-naped Wren split

The Rufous-naped Wren (Campylorhynchus rufinucha) is split into three species: Rufous-backed Wren (Campylorhynchus capistratus) from southern Mexico to Costa Rica, and two Mexican endemics, the Veracruz Wren (Campylorhynchus rufinucha) in Veracruz, and the Russet-naped Wren (Campylorhynchus humilis) in western Mexico. In Central America, that means that Rufous-naped Wren (Campylorhynchus rufinucha) becomes Rufous-backed Wren (Campylorhynchus capistratus).

• Rufous-backed Wren Campylorhynchus capistratus [map] [media] [my records]

Northern Flicker split

Guatemalan Flicker is split from the widespread Northern Flicker (Colaptes auratus). The latter is partially migratory but doesn’t reach Central America, so all resident flickers in northern Central America (Guatemala to Nicaragua) are now Guatemalan Flicker (Colaptes mexicanoides).

• Guatemalan Flicker Colaptes mexicanoides [map] [media] [my records]

Crested Bobwhite split

Crested Bobwhite is split into two species: Spot-bellied Bobwhite Colinus leucopogon from Guatemala to Costa Rica, and Crested Bobwhite Colinus cristatus from Costa Rica to northern Brazil. Note that the latter’s range in Costa Rica is tenuous; a population from adjacent Panama spread into extreme southwestern Costa Rica in the 1970s, and during the 1980s was even quite common there, but this range expansion does not seem to have been successful, with Costa Rican records having become scarcer each year since the early 1990s. Maybe the split provides a new incentive to look for (and document!) it in southwestern Costa Rica.

• Spot-bellied Bobwhite Colinus leucopogon [map] [media] [my records]
  • RANGE: Central America, from s. Guatemala to west-central Costa Rica
• Crested Bobwhite Colinus cristatus [map] [media] [my records]
  • RANGE: sw. Costa Rica to sw. Colombia, n. Brazil, and the Guianas

Long-tailed Woodcreeper split

The widespread Long-tailed Woodcreeper (Deconychura longicauda) has been split into three species, based on pronounced vocal differences. Central American populations are now called Piping Woodcreeper (Deconychura typica).

• Piping Woodcreeper Deconychura typica [map] [media] [my records]
  • RANGE: Middle America from se. Honduras to w. Panama, e. Panama (Darién), and n. Colombia

Plain Xenops split

Similar to the woodcreeper split, the Plain Xenops (Xenops minutus) is split into three species, based on vocal differences. All Central American populations are now Northern Plain-Xenops (Xenops mexicanus).

• Northern Plain-Xenops Xenops mexicanus [map] [media] [my records]
  • RANGE: Middle America (from tropical s. Mexico south) to nw. Colombia, w. Ecuador, and northernmost Venezuela

New genus Driophlox

Research has shown that the ant-tanagers of the genus Habia are not monophyletic, which means they are not each other’s closest relatives. To resolve monophyly in Habia, a new genus Driophlox was erected. In Central America, Red-throated Ant-Tanager Habia fuscicauda and Black-cheeked Ant-Tanager Habia atrimaxillaris will now be known as Red-throated Ant-Tanager Driophlox fuscicauda and Black-cheeked Ant-Tanager Driophlox atrimaxillaris.

The genera Calocitta and Psilorhinus are merged into Cyanocorax

The two magpie-jays, one of which occurs in our region, and the Brown Jay, join the other jays of the region into Cyanocorax. Thus, White-throated Magpie Calocitta formosa is now White-throated Magpie-Jay Cyanocorax formosus, and Brown Jay Psilorhinus morio is now Brown Jay Cyanocorax morio.

Other small name changes include the common names for all the parrots in the genus Amazona, which are now called Amazons. So, Yellow-naped Amazon, White-fronted Amazon, and so forth. They were already known by these names in other taxonomies (e.g. BirdLife International), so this change forms part of an ongoing unification effort into a standard world taxonomy for birds, carried out by the Working Group Avian Checklists. Another common name change only is the case of Audubon’s Shearwater Puffinus lherminieri, which now will known as Sargasso Shearwater Puffinus lherminieri.

It may take a week or so for the taxonomic dust to settle, so don’t be alarmed when at first you see your life list totals move around a little bit. These taxonomic changes reflect advances in our knowledge of avian systematics. Hopefully you will end up with a couple of armchair lifers!