Taxonomy update Central America 2017

By eBird Centroamérica agosto 14, 2017

Cabanis's Ground-Sparrow (Melozone cabanisi), a new Costa Rican endemic © Juan D Astorga / Macaulay Library

by John van Dort

Each year, the AOS (formerly AOU) updates their taxonomy, to reflect the latest insights into the taxonomic relationships of the birds of North America, which includes Central America. This year’s taxonomy changes are published in the Fifty-eighth supplement to the American Ornithological Society’s Check-list of North American Birds, published 5 July 2017 in the journal The Auk. eBird generally follows the AOS taxonomy, and on 15 August 2017, your old records will automatically be changed to reflect this new taxonomy. After the update, take a look at your life list and who knows, maybe you gained a few ‘armchair lifers’!

The following treats the relevant changes for the Central American region. All name changes are treated below. Some orders, families, and genera were rearranged, to better reflect current understanding of their evolutionary relationships. All name changes will be implemented into eBird, but not all order changes will be implemented into eBird this year. See the Fifty-seventh and Fifty-eighth supplements for more information about the new taxonomic order.

Magnificent Hummingbird (Eugenes fulgens)

Magnificent Hummingbird is split into Rivoli’s Hummingbird (Eugenes fulgens), found from southwestern USA to northern Nicaragua, and Talamanca Hummingbird (Eugenes spectabilis), found in Costa Rica and western Panama. Subtle differences between adult males of the two new species include the color of the gorget (yellow-green in Rivoli’s; turquoise in Talamanca) and the color of the underparts (blackish in Rivoli’s; dark green in Talamanca).

Adult male Talamanca Hummingbird (Eugenes spectabilis), February 2017, Savegre Mountain Lodge, San José, Costa Rica. Note the turquoise gorget and the green underparts. Photo © René Laperrière / Macaulay Library.

In comparison to the Talamanca Hummingbird, the Handbook of the Birds of the World (HBW Alive) mentions a stronger green back, slightly deeper green glittering throat and richer glittering purple crown for Rivoli’s. The adult males in northern Central America appear to be somewhat intermediate, showing a dark chest and a green belly. In the past, this group, isolated from the others by the Isthmus of Tehuantepec in the north and the Nicaragua Depression in the south, was described as a third subspecies—viridiceps—but for now the AOS decided to leave it with fulgens, pending further studies. Vocal differences may be a significant marker for species delineation, so we encourage birders in northern Central America to make recordings of this species.

Adult male Rivoli’s Hummingbird (Eugenes fulgens), October 2014, Montaña de Izopo, Francisco Morazán, Honduras. Photo © John van Dort / Macaulay Library. The dark chest band is absent in Talamanca Hummingbird.

Northern Harrier (Circus cyaneus)

Northern Harrier is split into Northern Harrier (Circus hudsonius) of the New World and Hen Harrier (Circus cyaneus) of the Old World. There are some plumage differences between juveniles and adult males, whereas adult females of the two species are quite similar. For birders in Central America, only the scientific name changes.

Split of Anas dabbling ducks into four genera

Some of our dabbling ducks have new scientific names now.

Blue-winged Teal (Anas discors) > Spatula discors

Cinnamon Teal (Anas cyanoptera) > Spatula cyanoptera

Northern Shoveler (Anas clypeata) > Spatula clypeata

Gadwall (Anas strepera) > Mareca strepera

American Wigeon (Anas americana) > Mareca americana

Others, like Northern Pintail and Green-winged Teal, remain in Anas.

New families for Passerellidae and Icteriidae

The New World Sparrows, such as Rusty Sparrow and Lincoln’s Sparrow, are now in their own family, Passerellidae. Yellow-breasted Chat, long considered a warbler in the Parulidae family but suspected not to be, now has its own family, the Icteriidae. This last family should not be confused with the Icteridae, i.e. the New World Blackbirds.

Emerald Toucanet split

Emerald Toucanet was split into Northern Emerald-Toucanet (Aulacorhynchus prasinus), found in Mexico and throughout Central America, and Southern Emerald-Toucanet (Aulacorhynchus albivitta), found in South America. This means that the white-throated form in northern Central America and the blue-throated form in southern Central America continue to form one species, at least according to AOS, now named Northern Emerald-Toucanet. (Note that the HBW and BirdLife International Checklist of the Birds of the World does not follow the AOS and has the blue-throated form from southern Central America split off from the white-throated form.)

For now, these two distinct forms will remain a single species, with a new name: Northern Emerald-Toucanet (Aulacorhynchus prasinus). Photos © Brian Sullivan (White-throated form from Belize) and Zak Pohlen (Blue-throated form, Costa Rica) / Macaulay Library.

Prevost’s Ground-Sparrow split

Prevost’s Ground-Sparrow was split into White-faced Ground-Sparrow (Melozone biarcuata), found from southern Mexico to central Honduras, and Cabanis’s Ground-Sparrow (Melozone cabanisi), endemic to Costa Rica. Facial patterns in the two newly-declared species are quite distinct, and the presence (Cabanis’s) or absence (White-faced) of a breast spot is another distinguishing mark.

Left: White-faced Ground-Sparrow (Melozone biarcuata), May 2017, Guatemala © Ian Davies / Macaulay Library. Right: Cabanis’s Ground-Sparrow (Melozone cabanisi), now a Costa Rican endemic © Andrew Spencer / Macaulay Library.

Genus change for Violet-bellied Hummingbird

Violet-bellied Hummingbird (Damophila julie), found in Panama, Colombia, and Ecuador, becomes Juliamyia julie.

Genus change for Red-breasted Meadowlark

Red-breasted Meadowlark (Sturnella militaris) becomes Leistes militaris.

Mangrove Rail is added to the Check-list

Populations of large rails on the Pacific coast of Central America were recently described as Mangrove Rail (Rallus longirostris), a species previously known from South America only. This change to the AOS checklist had already been silently implemented into eBird, but is now officially part of the AOS taxonomy.

It may be worth noting that avian taxonomy, at the end of the day, is always a work in progress, reflecting the latest insights into phylogenetic relationships and the evolution of birds. It should also be noted that such insights are often open for multiple interpretations: some taxonomists are ‘splitters’ and others are ‘lumpers’. Changes to AOS taxonomy are decided by the AOS’s Committee on Classification and Nomenclature—North and Middle America. eBird uses the Clements taxonomy for the world’s birds, which follows taxonomy decisions from multiple regions, and sometimes incorporates changes for birds in Central America before the AOS considers them.