447

COSTA RICAN [BAND-BACKED] WREN  Campylorhynchus [zonatus] costaricensis (p. 336). Vocal and

morphological differences indicate that the costaricensis group (s. Nicaragua to w. Panama) is best treated

as specifically distinct from zonatus group (Mexico to n. Nicaragua; Mesoamerican Wren) and brevirostris

group of nw. S America; also supported by molecular data (Vázquez-M. & Barker 2021).

HOUSE WREN  Troglodytes aedon (p. 344). Differences in voice, plumage, and ecology suggest that the

aedon group (N America; Northern House Wren), brunneicollis group (Mexico; Brown-throated Wren)

and musculus group (s. Mexico to S America; Southern House Wren) may represent separate species, along

with some Caribbean taxa in the House Wren complex.

PLAIN WREN  Cantorchilus modestus complex (p. 338). Although usually now treated as 3 species

(Cabanis’s Wren, Canebrake Wren, Isthmian Wren), we find the case for splitting Plain Wren into 3

species unconvincing, another instance of divergent mitochondrial lineages elevated to the level of species

by sophistry rather than science. With respect to possible vocal differences, the paper by Saucier et al.

(2015) and Saucier’s follow-up proposal to NACC were misleading at best, cf. Boesman (2016) and our

own analysis. Song differences among taxa are not at all clear, although there may be some differences

in scolding calls. Moreover, and perhaps unsurprisingly, Freeman & Montgomery (2017) found zero

discrimination between ‘Isthmian Wren’ and ‘Cabanis’s Wren’ in song playback experiments, yet their

finding of much greater discrimination led to lumping of Scarlet-rumped Tanager (Howell & Dyer 2022).

MIDDLE AMERICAN [WHITE-BREASTED] WOOD WREN  Henicorhina [leucosticta] prostheleuca

(p.  342). Vocal and morphological differences indicate that the prostheleuca group (Mexico to w.

Colombia) is best treated as specifically distinct from other S American populations.

WHISTLING [SOUTHERN NIGHTINGALE-] WREN  Microcerculus [marginatus] luscinia (p. 342)

Vocal and morphological differences indicate that the luscinia group (Costa Rica to Panama) is best

treated as specifically distinct from S American populations.

GRASS [SEDGE] WREN  Cistothorus [platensis] elegans (p. 344). We follow the study by Robbins &

Nyári (2014) who advocated splitting the Sedge Wren complex into 8 species, including elegans of Middle

America.

ROCK WREN  Salpinctes obsoletus (p. 344). Differences in voice and plumage suggest that the obsoletus

group (N America to cen. Mexico; Northern Rock Wren) and guttatus group (s. Mexico to Costa Rica;

Southern Rock Wren) may represent separate species.

NORTHERN [LONG-BILLED/TRILLING] GNATWREN  Ramphocaenus [melanurus] rufiventris

(p. 346). Differences in voice and plumage indicate that the rufiventris group (Mexico to nw. Peru) is best

treated as specifically distinct from other S American populations of the R. melanurus complex.

CENTRAL AMERICAN [WHITE-LORED] GNATCATCHER  Polioptila [albiloris] albiloris (p.  346).

Differences in morphology and voice between the vanrossemi group (w. Mexico; Van Rossem’s Gnatcatcher)

and albiloris group (Guatemala to Costa Rica) indicate that cryptic species are probably involved.

YELLOW-GREEN [SCRUB] GREENLET  Hylophilus [flavipes] viridiflavus (p. 348). Differences in voice

and plumage indicate the viriflavidus group (Costa Rica to Panama) and flavipes group (n. S America;

Scrub Greenlet) are best treated as separate species.

MANGROVE VIREO  Vireo pallens (p. 350). Differences in voice, morphology, and ecology suggest the

pallens group (Mexico to Costa Rica, Pacific coast) and semiflavus group (Mexico to Nicaragua; Mayan

Vireo) may best be treated as separate species. Differences between them are as great or greater than

between other vireo taxa treated as species, such as Red-eyed Vireo and Chivi Vireo V. chivi.

SOUTHERN BROWN-CAPPED VIREO  Vireo [leucophrys] leucophrys (p. 352). Differences in voice and

plumage indicate that the amauronotus group (Mexico to Nicaragua; Northern Brown-capped Vireo) and

leucophrys group (Costa Rica to S America) are best treated as separate species.

EASTERN WARBLING VIREO  Vireo [gilvus] gilvus (p. 352). Differences in voice, morphology, and

ecology indicate that the gilvus group (breeding in e. N America) and swainsoni group (breeding w. N

America to Mexico) may best be considered separate species.

MANGROVE WARBLER  Setophaga petechia (p. 434). Taxonomy of Mangrove Warbler complex remains

vexed; taxon aureola of Cocos and Galapagos Islands perhaps best treated as a full species, Galapagos Warbler.