Neotropical Birds taxonomy update 2014

Neotropical Birds follows the taxonomy and nomenclature of the eBird/Clements Checklist, which is updated annually in August. Here we briefly review some of the more important changes, at the species level, that are incorporated in the 2014 revisions to the eBird/Clements Checklist; full documentation of all changes will be posted on the eBird and Clements Checklist websites. The eBird/Clements Checklist, in turn, is based on work of the two checklist committees of the American Ornithologist’s Union, the AOU Committee on Classification and Nomenclature of North and Middle American Birds (“North American Classification Committee,” NACC) and the South American Classification Committee (SACC).

Important changes at the species level (splits and lumps) in 2014 are:

1) Split within Herald Petrel (Pterodroma arminjoniana)

Pterodroma petrels are poorly known seabirds: they typically breed on remote oceanic islands, are highly pelagic for most of their lives, many species have relatively simple plumage patterns, and the differences between species sometimes are obscured by the presence of two or more color morphs within some species. This year’s taxonomic change affects species that are only rare (but regular) nonbreeding visitors to the Neotropics. Following an influential paper by the great seabird biologist Robert Cushman Murphy (Murphy and Pennoyer, 1952, Larger petrels of the genus Pterodroma, American Museum Novitates number 1580), populations breeding in the Atlantic and Indian Oceans (subspecies arminjoniana, Trindade Petrel) were considered conspecific with populations breeding in the central Pacific Ocean (subspecies heraldica, Herald Petrel). Modern seabird biologists have shown a greater tendency to classify Trindade and Herald petrels as separate species, and SACC recently followed suit. This split is based on consideration of several factors, including size, structure, and plumage differences between the two, and the fact that Trindade is sexually dimorphic in size but Herald is not. Both species also breed on Round Island, in the Indian Ocean, although Herald Petrel is very rare there, and there are complicated patterns of hybridization on Round Island that also involve other species of Pterodroma that breed there (Kermadec Petrel Pterodroma neglecta and Henderson Petrel Pterodroma atrata) (Brown, R.M., W.C. Jordan, C.G. Faulkes, C.G. Jones, L. Bugoni, V. Tatayah, R.L. Palma, and R.A. Nichols. 2011. Phylogenetic relationships in Pterodroma petrels are obscured by recent secondary contact and hybridization. PLoS ONE 6(5): e20350). Otherwise these taxa seem to maintain their genetic distinctiveness, and so, on balance, are best considered as separate species.

Herald Petrel is a rare but probably regular nonbreeding visitor to the northeastern Pacific Ocean, north to ca 15º N (off of western Mexico), and breeds well of the coast of Chile (Easter Island). Trindade Petrel breeds on islands in the South Atlantic, off the coast of Brazil, and occurs north to the Gulf Stream off the east coast of the United States. It is now found regularly on pelagic trips off North Carolina, and probably occurs regularly in deep, warm water as far north as waters off of New York and Massachusetts. There also are three records from the Caribbean (Bahamas, Puerto Rico, and Guadeloupe).

2) Multiples splits within the Clapper/King Rail complex (Rallus longirostris/Rallus elegans)

Clapper and King rails occur in marshes and mangroves from the northern United States south, locally, to southern Brazil. Both species are geographically variable. In many areas Clapper and King rails are completely allopatric, or have distributions that are parapatric, meeting narrowly along an environmental gradient. Locally, in the eastern United States, Clapper and King rails hybridize where they come into contact with one another. Consequently some authors considered these to represent a single widespread but highly variable species (e.g. Ripley, 1977, Rails of the world, Godine Publishing, Boston, Massachusetts). Most authors continued to recognize two species, however, partitioned by habitat: King Rails are restricted to fresh water marshes, with Clapper Rails in salt water marshes and in mangroves. This solution seems logical on the face of it, but never was completely satisfactory either. To cite just one apparent problem, populations of California and northwestern Mexico, that are “Clapper” Rails because they occur in salt water marshes, more closely resemble King Rails than they do many other subspecies of Clapper Rails.

Early surveys of the Clapper/King rail complex with molecular approaches were inconclusive. More recently Maley and Brumfield (2013, Mitochondrial and next-generation sequence data used to infer phylogenetic relationships and species limits in the Clapper/King rail complex, Condor 115: 316-329) undertook a more comprehensive approach with more powerful DNA sequencing techniques, and emerged with a well resolved phylogeny for these rails. Among the results of this phylogeny are that “King” Rails of fresh water marshes of the highlands of central Mexico are more closely related to the “Clapper” Rails of salt water marshes of California and northwestern Mexico than they are to “true” King Rails of eastern North America; and that King Rails of eastern North America are more closely related to Clapper Rails of eastern North America and the Caribbean, than these Clapper Rails are to “Clapper” Rails of mangroves of South America.

The resulting taxonomy leaves us with a split of King Rail into two species (Chesser et al., 2014, Fifty-fifth supplement to the American Ornithologists’ Union Check-list of North American Birds, Auk: in press): King Rail (Rallus elegans) of eastern North America, and Aztec Rail (Rallus tenuirostris) of central Mexico; and a split of Clapper Rail into three species: Clapper Rail (Rallus crepitans) of eastern North America and the Caribbean; Ridgway’s Rail (Rallus obsoletus) of California and northwestern Mexico); and Mangrove Rail (Rallus longirostris) of coastal South America. Note that the scientific name Rallus longirostris, which formerly was associated with Clapper Rail, now is assigned to Mangrove Rail; and that Clapper Rail now has a different scientific name. The English name of Rallus obsoletus honors Robert Ridgway (1850-1929), an ornithologist who was a founder of the American Ornithologists’ Union, who described dozens of new species and subspecies of birds (including both Rallus obsoletus and Rallus tenuirostris), and whose monumental Birds of North and Middle America continues to be a valuable reference on bird plumages, morphometrics, molts, and taxonomy.

3) Split of Bearded Helmetcrest (Oxypogon guerinii) into four species

Helmetcrests are attractive but poorly known hummingbirds of paramo habitats in the Andes of Colombia and Venezuela. The distribution of helmetcrests is disjunct, with four main populations isolated from one another in different regions of the Andes: in the central Andes of Colombia (stubelii); in the eastern Andes of Colombia (guerinii); in the Sierra Nevada de Santa Marta, in northern Colombia (cyanolaemus); and in the Andes of northwestern Venezuela (lindenii). Each population is morphologically distinct, but at least since 1945, most authors have included all four within a single species. Collar and Salaman (2013, The taxonomic and conservation status of the Oxypogon helmetcrests, Conservación Colombiana 19: 31-38) reviewed geographic variation within helmetcrests, and concluded that the differences between each subspecies were as great the differences between different species in other genera of hummingbirds. SACC agreed with this proposal, and so now four species of helmetcrest are recognized: Buffy Helmetcrest (Oxypogon stubelii), Blue-bearded Helmetcrest (Oxypogon cyanolaemus), White-bearded Helmetcrest (Oxypogon lindenii), and Green-bearded Helmetcrest (Oxypogon guerinii). All of these helmetcrests are rather poorly known, but Blue-bearded Helmetcrest of the Santa Martas emerges as a species of heightened conservation concern, as it has not been reported since 1946.

4) Split Bicolored Antbird (Gymnopithys leucaspis) into two species

A medium sized, brown and white (“bicolored”) antbird is widespread in the lowlands from Honduras south to northwestern Amazonia. Throughout its range, this is an “obligate” ant follower, meaning that it always forages at swarms of army ants, preying on arthropods that are trying to escape the ants. Despite the simplicity of the overall plumage pattern, there nonetheless are subtle plumage differences between the populations in Central America and in South America west of the Andes (the “true” “Bicolored” group), and the populations in Amazonia (the “White-cheeked” group): western birds have black cheeks, bordered above the gray, and the flanks and sides of the breast are brown, whereas Amazonian birds have black and white cheeks that are bordered above with brown, and have black sides to the breast and flanks. Many authors have recognized two species, separated by the Andes, while other authors treated them all as a single species. Brumfield et al. (2007, Phylogenetic conservatism and antiquity of a tropical specialization: army-ant-following in the typical antbirds (Thamnophilidae), Molecular Phylogenetics and Evolution 45: 1-13) prepared a phylogeny of all ant-following antbirds, using DNA sequence data. One interesting, and unexpected, result was that the Bicolored Antbirds of western Amazonia were more closely related to Rufous-throated Antbird (Gymnopithys rufigula), a brown and rufous antbird of northeastern South America, than they were to more similar appearing populations of Bicolored Antbird west of the Andes. Therefore both NACC (Chesser et al. 2014) and SACC have split Bicolored Antbird into two species, the northern and western Bicolored Antbird (Gymnopithys bicolor), from Honduras south to western Ecuador; and White-cheeked Antbird (Gymnopithys leucaspis) of Amazonia.

5) Spotted Antpitta (Hylopezus macularius) is split into two species, and a related species (Alta Floresta Antpitta Hylopezus whittakeri) is described as new to science

Antpittas are notoriously shy and difficult to observe, usually staying within dense cover. Some Andean species of antpittas now are seen regularly at feeding stations, but Amazonian antpittas remain particularly poorly known and difficult to study. Spotted Antpitta is widespread in central Amazonia, with more isolated populations scattered across northwestern Amazonia. A species of antpitta from southwestern Amazonia, Masked Antpitta (Hylopezus auricularis), formerly was classified as a subspecies of Spotted Antpitta, until Maijer (1998, Rediscovery of Hylopezus (macularius) auricularis: distinctive song and habitat indicate species rank, Auk 115: 1072-1073) documented that it was vocally distinct. Masked Antpitta also was, by antpitta standards, distinctive in plumage as well. All other populations of Spotted Antpitta are similar to one another in size and plumage. Carneiro et al. (2012, Systematic revision of the Spotted Antpitta (Grallariidae: Hylopezus macularius), with description of a cryptic new species from Brazilian Amazonia, Auk 129: 338-351) reviewed variation in plumage and in song across the range of Spotted Antpitta, and also used DNA sequence data to construct a phylogeny for these populations. Patterns of variation across these different data sets were similar, and indicated three major groups within Spotted Antpitta: one north of the Amazon, from Peru to eastern Brazil; one south of the Amazon and east of the Xingu River; and one south of the Amazon, between the Madeira and Xingu rivers. This last population did not have a name (!), and so Carneiro et al. described it as a new species, Alta Floresta Antpitta (Hylopezus whittakeri). Each of the two other groups is split as a separate species, Spotted Antpitta (Hylopezus macularius) north of the Amazon, and Snethlage’s Antpitta (Hylopezus paraensis) of eastern Brazil south of the Amazon. The English name for Hylopezus paraensis honors Emilie Snethlage (1868-1929), an extraordinary woman who was a pioneering ornithologist in Brazil, famous in particular for her explorations of Amazonia. Alta Floresta Antpitta is named whittakeri in honor of “Andrew (‘Andy’) Whittaker, whose contributions to Amazonian ornithology over the past 20 years resulted in the description and rediscovery of several species, new country records, and many noteworthy range extensions” (Carneiro et al. 2012).

6) Split White-winged Black-Tyrant (Knipolegus aterrimus) into two species

Males of most species of Knipolegus are black, which perhaps has obscured the relationships within the genus. White-winged Black-Tyrant is one of the most widespread and familiar members of the genus, occurring in the Andes from northern Peru south to Argentina, and also occurs in the lowlands in central Argentina. There also is a very disjunct population in eastern Brazil, franciscanus, that traditionally has been classified as a subspecies of White-winged; some recent authors have classified franciscanus as a separate species, however (e.g. Ridgely and Tudor, 2009, Field guide to the songbirds of South America: the passerines, University of Texas Press, Austin, Texas). Hosner and Moyle (2012, A molecular phylogeny of black-tyrants (Tyrannidae: Knipolegus) reveals strong geographic patterns and homoplasy in plumage and display behavior, Auk 129: 156-167) constructed a phylogeny of black-tyrants, using data from DNA sequences. Perhaps not surprisingly, they found that franciscanus of eastern Brazil is more closely related to two other Brazilian species of black-tyrant, Crested Black-Tyrant (Knipolegus lophotes) and Velvety Black-Tyrant (Knipolegus nigerrimus), than it is to White-winged Black-Tyrant of the Andes. Therefore franciscanus is split as a separate species, Caatinga Black-Tyrant (Knipolegus franciscanus).

7) Split Andean Tyrant (Knipolegus signatus)

Andean Tyrant includes two subspecies, signatus of northern and central Peru, and cabanisi, from southeastern Peru to northern Argentina. These are poorly known birds, and signatus, in particular, is not often seen (and apparently was not reported at all between 1873 and 1973!). These two were classified in different genera (!) until Traylor (1982, Notes on tyrant flycatchers (Aves: Tyrannidae), Fieldiana Zoology new series number 13) clarified their status as congeners. A phylogeny of Knipolegus based on DNA sequence data confirms that signatus and cabanisi are sister taxa (Hosner and Moyle, 2012, A molecular phylogeny of black-tyrants (Tyrannidae: Knipolegus) reveals strong geographic patterns and homoplasy in plumage and display behavior, Auk 129: 156-167), and that the level of genetic divergence between them is relatively high. These two populations also differ from one another in plumage in both males and in females. They now are recognized as separate species, Jelski’s Black-Tyrant (Knipolegus signatus) and Plumbeous Black-Tyrant (Knipolegus cabanisi). The English name of Knipolegus signatus honors Konstanty Jelski, a Polish naturalist who made important 19th collections in Peru, and who collected the first specimens of signatus.

8) Sirystes (Sirystes sibilator) is split into four species

Sirystes is a flycatcher that is widespread in the lowlands, from Panama south to southern Brazil. These birds are similar in size and proportions to Myiarchus flycatchers, and, like Myiarchus, Sirystes nest in cavities in trees. There are four subspecies of Sirystes, which some authors have divided into two species, separated by the Andes, based in large part of vocal differences between these groups (e.g. Ridgely and Tudor, 2009, Field guide to the songbirds of South America: the passerines, University of Texas Press, Austin, Texas). Donegan (2013, Vocal variation and species limits in the genus Sirystes (Tyrannidae), Ornitología Colombiana 19: 11-30) made a case, however, that there also is significant variation in vocalizations within the three subspecies of Sirystes from east of the Andes. This results in the recognition of four species of Sirystes: Choco Sirystes (Sirystes albogriseus), from Panama to northwestern Ecuador; White-rumped Sirystes (Sirystes albocinereus), of western Amazonia; Todd’s Sirystes (Sirystes subcanescens) of northeastern South America; and Sibilant Sirystes (Sirystes sibilator) of eastern and east central Brazil, Paraguay, and northeastern Argentina. Donegan’s review of the Sirystes complex also suggests that these flycatchers are not as widespread as previously was thought, and that these flycatchers are absent – or at least rare and patchy – in large areas, especially in south central Amazonia.

9) Plain-breasted Earthcreeper (Upucerthia jelskii) is lumped with Buff-breasted Earthcreeper (Upucerthia validirostris)

The current trend in bird systematics is for phylogenetic analyses and reviews of geographic variation to discover previously unrecognized or underappreciated levels of divergence; as a result, taxonomic splits are more frequent that lumps. But sometimes a comprehensive review of variation reveals that “there is no there there”, and that differences between different species are trivial or nonexistent. Such is the case with a group of earthcreepers (Upucerthia) that occur from central Peru to northern Argentina. Traditionally these were recognized as two species, Plain-breasted Earthcreeper (Upucerthia jelskii) from Peru south to northernmost Argentina, and Buff-breasted Earthcreeper (Upucerthia validirostris) of northwestern Argentina. These two long have been recognized as closely related, but most authors considered them to form two species. This classification was based in part on a report of Buff-breasted from southern Bolivia (Cabot, 1990, First record of Upucerthia validirostris from Bolivia and new Bolivian distributional data, Bulletin of the British Ornithologists’ Club 110: 103-107), implying that these two would overlap geographically. This critical specimen apparently has not been reexamined, but now is suspected to represent a Plain-breasted Earthcreeper, not Buff-breasted (e.g., Mazar Barnett and Pearman, 2001, Lista comentada de las aves Argentinas/Annotated checklist of the birds of Argentina, Lynx Edicions, Barcelona). Areta and Pearman (2013, Species limits and clinal variation in a widespread high Andean furnariid: the Buff-breasted Earthcreeper (Upucerthia validirostris), Condor 115: 131-142) documented that there is a narrow (ca 80 km wide) distributional gap in Argentina between the two, but also that the vocalizations of Plain-breasted and Buff-breasted earthcreepers are identical, and that the two “species” respond to playback of vocalizations of the other. Areta and Pearman recommended that only a single species be recognized, Buff-breasted Earthcreeper (Upucerthia validirostris), a proposal that was endorsed by SACC. And yes, the scientific name jelskii honors the same Polish naturalist who discovered Andean Tyrant (Knipolegus signatus).

10) Split within Dark-eyed Junco

Juncos breed in forests across much of North America. Across this vast region, juncos vary noticeably in plumage. Previously almost every taxon of junco was considered to be a different species. Almost all juncos have a similar song, a simple trill; although contact between adjacent populations of juncos usually is limited, they typically hybridize where they meet; and to date there is little evidence of genetic differentiation across the genus, despite the variation in plumage. Consequently most taxa have been “lumped” into a single species (Dark-eyed Junco Junco hyemalis). In a sharp break from this trend, the junco population that is endemic from the island of Guadalupe on the west coast of Baja California, is elevated to species rank as Guadalupe Junco (Junco insularis), in accord with NACC (Chesser et al. 2014). The insular Guadalupe Junco is most similar morphologically to the Pink-sided Junco (J. h. mearnsi) of the Rocky Mountains. Guadalupe Junco differs from other Dark-eyed Junco populations in having a more complex song (the song is not a trill at all), and recent genetic (mtDNA) and morphometric evidence supports the elevation of J. insularis to full species (Mirsky 1976; Aleixandre et al. 2013). Guadalupe Junco is considered to be Critically Endangered, owing primarily to intense habitat degradation by introduced herbivores (feral goats). Goat removal beginning in the early 2000’s, and several management and conservation initiatives alongside the establishment of Guadalupe Island and its surrounding marine zone as a biosphere reserve in 2005, show potential to increase population numbers (Junak et al. 2003; Luna-Mendoza 2011). Watch an informative video about the Guadalupe Junco here.

11) Add a newly described species, Tropeiro Seedeater (Sporophila beltoni)

Several new species are described globally each year, with many of these new species coming from the Neotropics. Often new species are restricted to remote and rarely visited regions, but sometimes a new species is detected when a long-known pattern of geographic variation received renewed attention. Such is the case with the newly described Tropeiro Seedeater of southern Brazil. Hellmayr (1938, Catalogue of birds of the Americas, Part XI, Field Museum of Natural History Zoological Series volume 13, part 11: footnote, page 178) noted that some specimens of the widespread Plumbeous Seedeater (Sporophila plumbea) had bills that were bright orange rather than the typical dusky, and noted that specimens with both bill colors had been collected at the same site. This variation attracted little further attention until Repenning and Fontana (2013, A new species of gray seedeater (Emberizidae: Sporophila) from upland grasslands of southern Brazil, Auk 130: 791-803) documented that the yellow-billed birds differed from Plumbeous Seedeater not only in bill color, but also in morphometrics, in male plumage, in song, and in breeding habitat. This evidence indicates that the yellow-billed seedeater represents a distinct species; as it lacked a name, Repenning and Fontana described it as Tropeiro Seedeater (Sporophila beltoni). The English name of this species “refers to the breeding distribution and migratory pattern of the species, which is congruent with the Rota dos Tropeiros (Herders’ Trail). This inland trail was used for general travel and to drive herds (cattle, mules, and horses) and transport charque (beef jerky) from the south to markets in southeastern Brazil. This cycle began in the early 18th century and continued until 1930″ (Repenning and Fontana 2013: 794). The species name, beltoni, honors the late William “Bill” Belton, “an American diplomat who brilliantly revealed with extreme skill and scientific rigor the fantastic world of the birds of Rio Grande do Sul [Brazil]” (Repenning and Fontana 2013: 794).