During the summer months of each year, the annual supplement to the AOS (formerly AOU) Check-list of North American Birds is released. This supplement reflects recent accepted proposals to change the nomenclature and classification of birds on the official check-list including inclusions or removal of species level taxa. Since eBird generally follows the AOS checklist, as with previous supplements, we can expect name changes from the 2018 supplement to be shown in our eBird lists. Sometimes eBird deviates from AOS, and this year that happened with two species. More details below.
Of primary concern to many birders is whether or not certain species are “split” or “lumped”. This year, the Central American region gains three additional, newly recognized species as the result of splits, but “loses” two species because of lumping.
These are the changes that affect the region:
The Splits
Buff-throated Foliage-gleaner (Automolus ochrolaemus) [map] [media] [my records] is split into two species, a bird of the same name that mostly occurs on the Atlantic (Caribbean) slope of Central America to eastern Panama and South America, and the newly described Chiriqui Foliage-gleaner (Automolus exsertus) [map] [media] [my records] endemic to southern Costa Rica and western Panama.
This split was based on genetic studies that indicated a 6% difference between these two taxa along with playback experiments whereby there was no significant recognition of each other’s songs. It may be of further note to eBirders that there are at least two other distinct song types found in Buff-throated Foliage-gleaners that may indicate additional splits awaiting this species, notably in taxa from eastern Panama and the Choco region, and the Amazon basin.
This Chiriqui Foliage-gleaner may not look much different from the related Buff-throated Foliage-gleaner but it does make distinct vocalizations, especially for a Furnarid. Compare the following songs. Photo © Armand Munteanu / Macaulay Library.
A Buff-throated Foliage-gleaner from Rancho Naturalista, the Caribbean slope of Costa Rica. Recording © Mary Beth Stowe / Macaulay Library.
A Chiriqui Foliage-gleaner from southern Costa Rica. Recording © Jay McGowan / Macaulay Library.
And, as a reminder for eBirders to never shy away from uploading recordings and other media, note the difference in the song of a Buff-throated Foliage-gleaner from the Amazon:
Buff-throated Foliage-gleaner. Recording © Will Sweet / Macaulay Library.
Paltry Tyrannulet (Zimmerius vilissimus) was split into four species, two of which occur in Central America. Guatemalan Tyrannulet (Zimmerius vilissimus) [map] [media] [my records] occurs in the highlands of Chiapas (Mexico), Guatemala, Honduras, and El Salvador. Mistletoe Tyrannulet (Zimmerius parvus) [map] [media] [my records] occurs in the lowlands of southern Belize, the Petén (Guatemala) south along the Caribbean slope of Honduras to the Chocó region in nw Colombia. The two new South American tyrannulets are Spectacled Tyrannulet (Zimmerius improbus) in the Santa Marta, Sierra de Perijá, and northern Andes of Colombia and Venezuela; and Venezuelan Tyrannulet (Zimmerius petersi) of the coastal cordillera of n Venezuela (s Lara east to Miranda).
Guatemalan Tyrannulet – Zimmerius vilissimus. Photo © Tim Lenz / Macaulay Library.
Mistletoe Tyrannulet – Zimmerius parvus. Photo © Jay McGowan / Macaulay Library.
Vermiculated Screech-Owl (Megascops guatemalae) was also split. Three new species are the result, two of which occur in Central America. Middle American Screech-Owl (Megascops guatemalae) [map] [media] [my records] occurs from Mexico south to Costa Rica, and possibly east to central Panama on the Atlantic coast (more documentation of vocalizations are needed from Panama west of the Canal Zone). Also new is Choco Screech-Owl (Megascops centralis) [map] [media] [my records] which occurs from central Panama (possibly west to the Pacific Slope of se. Costa Rica–again, more audio recordings are needed from this zone) south to western Ecuador. A third split from Vermiculated Screech-Owl occurs outside the Central American region: Foothill Screech-Owl (Megascops roraimae) which has fairly widely-separated populations on the tepuis of southern Venezuela, adjacent northern Brazil, southern Guyana, and Suriname and Andean foothills from Venezuela and Colombia south to Bolivia. Both Middle American Screech-Owl and Foothill Screech-Owl have two subspecies groups that are also recognized.
Middle American Screech-Owl – Megascops guatemalae. Photo © Luis Trinchan / Macaulay Library.
Choco Screech-Owl – Megascops centralis. Photo © John van Dort / Macaulay Library.
Of concern for birders who travel to western Mexico is the recognition of Cinnamon-rumped Seedeater (Sporophila torqueola). The split of this endemic to western Mexico from White-collared Seedeater (Sporophila torqueola) has also resulted in the renaming of White-collared Seedeater to Morelet’s Seedeater (Sporophila morelleti) [map] [media] [my records], a bird found in many parts of Central America.
The Lumps
Scarlet-rumped Tanager (Ramphocelus passerini) [map] [media] [my records] is again considered to be one species and not the Passerini’s Tanager (R. passerini) and Cherrie’s Tanager (R. costaricensis) due to low genetic differences and mutual song recognition.
It’s easy to see why Scarlet-rumped Tanager is a much more descriptive name. Photo © Ken Murphy / Macaulay Library.
Similar arguments were used to lump the subspecies of Masked Yellowthroat (Geothlypis aequatorialis chiriquensis) from the border area of southern Costa Rica and western Panama with the Olive-crowned Yellowthroat (Geothlypis semiflava). Often considered a separate species known as Chiriqui Yellowthroat [map] [media] [my records], despite at least one pronounced morphological difference, this distinct subspecies was lumped with its Caribbean slope counterpart based on low genetic difference and mutual song recognition.
New Families
Two new avian families are now recognized in Central America, both of which have been split from currently recognized ones based on genetic studies.
Hydrobatidae, the storm-petrel family has been split into two families. These are:
- Hydrobatidae – Northern Storm-Petrels
- Oceanitidae – Southern Storm-Petrels
Wilson’s, White-faced, and Black-bellied Storm-Petrels are the members of the Oceanitidae that are expected to occur in Central America. All other storm-petrel species in our region pertain to the Hydrobatidae family.
The other addition to bird families found in Central America is a “new” family of flycatchers known as the Onychorhynchidae. This includes the royal-flycatchers, Ruddy-tailed Flycatcher, and Myiobius species and was recognized as a distinct family after genetic studies showed that these taxa are more closely related to the Sharpbill than tyrant-flycatchers!
Name Changes
These are a few changes to English and Latin names for species on the AOS Check-list of North American Birds.
Tahiti Petrel (Pterodroma rostrata) changes to (Pseudobulweria rostrata)
Ladder-backed Woodpecker (Picides scalaris) changes to (Dryobates scalaris)
Hairy Woodpecker (Picoides villosus) changes to (Dryobates villosus)
Smoky-brown Woodpecker (Picoides fumigatus) changes to (Dryobates fumigatus)
Red-rumped Woodpecker (Picoides kirkii) changes to (Dryobates kirkii)
Mouse-colored Tyrannulet (Phaeomyias murina) changes to (Nesotriccus murina)
There is also one name change in English:
Red-breasted Blackbird (Leistes militaris) changes to Red-breasted Meadowlark.
These and other changes to the taxonomy followed by the AOS are made by the AOS’s Committee on Classification and Nomenclature for North and Middle America. Although eBird generally tracks and incorporates the decisions of this committee, since eBird uses the Clements taxonomy, eBird also incorporated changes to Central American taxonomy not taken into consideration by the AOS. For more details about the changes made to the eBird taxonomy, please see eBird Central’s world-wide 2018 taxonomy update article.