Systematics

Up to 14 subspecies of Brown-capped Vireo are recognized:

eleanorae, described as Vireo gilvus eleanorae Sutton and Burleigh 1940; type locality 6 miles north of Jacala, Hidaldgo, Mexico.

Occurs in northeastern Mexico (southern Tamaulipas, San Luis Potosí, and northern Hidalgo) (Blake 1968). Phillips (1991) suggests that eleanorae is partially migratory, with part of the population moving south to Puebla in the nonbreeding season.

dubius, described as Vireosylva amauronota (?) dubia (Phillips 1991); type locality Galindo, Tamaulipas, Mexico.

Occurs in southwest central Tamaulipas, Mexico.

"Paler and duller above than eleanorae or amauronota. Somewhat darker and browner above than V. [gilvus] swainsonii sympatrica, particularly on crown, but remarkably similar" (Phillips 1991: 217).

amauronotus, described as Vireo amauronotus Salvin and Godman 1881; type locality Orizaba, Mexico.

Occurs in south central Mexico in Puebla and Veracruz (Blake 1968, Phillips 1991).

strenuus, described as Vireo amauronotus strenuus Nelson 1900; type locality Tumbala, Chiapas, Mexico.

Occurs in northern Chiapas (Phillips 1991); presumably this also is the subspecies that occurs in central Guatemala (see Eisermann and Avendaño 2007: 26).

bulli, described as Vireo gilvus bulli Rowley 1968; type locality Cerro Baúl, above Rancho Vicente, Oaxaca, Mexico.

Occurs in eastern Oaxaca, Mexico; presumably this also is the subspecies that occurs in southwestern Guatemala (see Eisermann and Avendaño 2007: 26).

"Crown and nape darker (more blackish brown) than any of the presently recognized Mexican geographic races of Vireo gilvus; upper parts, including wing coverts, blackish olive rather than light brownish olive-green as in amauronotus, connectens, 'eleanorae', and strenuus; primaries and rectrices more black than those of all specimens of other races used in this study; breast and belly more white and with less greenish tinge; crissum very pale lemon yellow, much lighter in color than in the other subspecies" (Rowley 1968). "Still darker, sootier above, than strenua, less rufescent; crissum paler yellowish. (Larger?)" (Phillips 1991: 218).

Rowley named this subspecies in honor of his "esteemed friend Dan Bernard Bull, of La Mesa, California, who has devoted a lifetime to the study of ornithology and oölogy" (Rowley 1968: 7).

palmeri, described as Vireosylva amauronota palmeri Phillips 1991; type locality Cantoral, Honduras.

Occurs in Honduras and possibly El Salvador.

"Back bright (rather greenish) Citrine Drab (¿) to almost Saccardo's Olive (¿) in decided contrast to crown, which is a bit paler, less rufescent, then strenua (but still sootier than amauronota and [northern] races. Bend of wing and under wing-coverts more definitely tinged with yellowish than in these races, and crissum strongly washed with deep Ivory Yellow. Thus decidedly brighter, less uniform, than races to W and N, but less so than V. leucophrys costaricensis, etc." (Phillips 1991: 218).

Phillips named this subspecies after Ralph S. Palmer, "in slight recognition of the importance and lasting value of his extensive contributions to the zoology, and especially ornithology, of this continent" (Phillips 1991: 218).

costaricensis, described as Vireo josephæ costaricensis Ridgway 1904; type locality San José, Costa Rica.

Occurs in northern and central Costa Rica.

"Similar to V. j. josephæ but pileum paler sooty brown, yellow of under parts deeper, wing shorter, and tail longer; also resembling V. amauronota, but color of pileum browner and extending over hindneck, back, etc. oily olive-green, superciliary stripe more sharply defined (especially the posterior portion), and under parts of body wholly light yellow" (Ridgway 1904). "Underparts (posterior to chest) distinctly pale yellow, and rump more yellowish olive. Crown paler, more brownish" (Phillips 1991: 218).

chiriquensis, described as Vireo josephae chiriquensis Bangs 1903; type locality Boquete, Volcán de Chiriquí, Panama.

Occurs in southern Costa Rica and western Panama.

"Similar to V. j. costaricensis but much grayer above, the pileum and hindneck dark hair brown instead of deep sooty brown, the back, etc., grayish olive or dull grayish olive-green instead of bright brownish olive-green, superciliary stripe more extensively grayish posteriorly, brownish postocular streak grayer and less distinct, and yellow of under parts decidedly paler" (Ridgway 1904: 161). "Very slightly duller, darker, and grayer above than costaricensis, and paler yellow below" (Phillips 1991: 219).

dissors, described as Vireo gilvus dissors Zimmer 1941; type locality Cerro Munchique, west of Popoyan, Colombia. Includes disjunctus Zimmer 1941 (see Olson 1981).

Occurs in eastern Panama (Darién) and in the western and central Andes of Colombia (Zimmer 1941, Olson 1981).

"Differs from V. g. leucophrys of eastern Colombia by slightly darker cap of a more grayish, less warmly hued, brown; back distinctly greener, less brownish olive; under parts not distinctive. Differs from V. g. josephae of western Ecuador by somewhat lighter colored cap, paler and more greenish-olive back, and more restricted white throat patch with stronger yellowish flammulations on its lower portion. Differs from V. g. chiriquensis of Panamá by duller and more greenish-olive back and paler yellow under parts. Differs from V. g. maranonicus of north-central and northwestern Perú by lighter cap, paler and duller (often more greenish) back, and lighter yellow under parts" (Zimmer 1941: 18).

leucophrys, described as Hylophilus leucophrys (Lafresnaye 1844); type locality Colombia

Occurs from the Eastern Andes of Colombia (including the head of the Magdalena Valley) south along the east slope of the Andes of Ecuador to central Peru.

mirandae, described as Vireo josephae mirandae Hartert 1917; type locality Galiparo [= Galipán], Cerro del Avila, Venezuela

Occurs in the Sierra Nevada de Santa Marta, Colombia, in the Andes of Venezuela, and in the coastal mountains of Venezuela east to Sucre.

josephae, described as Vireo josephae Sclater 1859; type locality Pallatanga, Ecuador.

Occurs in western Ecuador, and extreme southwestern Colombia.

"The birds of western Ecuador [josephae] are distinguished from those of adjacent parts of most of Colombia, eastern Ecuador, and Perú by their dark caps (usually dark Chaetura Drab), dark olive backs, and extensive white area on the throat, usually carried well over the chest where, however, then may be some yellowish edging or flammulation. The extent of this white usually is as great as in mirandae although the latter form has a distinctly paler cap" (Zimmer 1941: 17).

maranonicus, described as Vireo gilvus maranonicus Zimmer 1941; type locality Chaupe, near San Ignacio, Río Chinchipe, Peru

Occurs on both slopes of the western Andes of northern Peru.

"Similar to the lighter examples of V. g. josephae of western Ecuador in respect to the color of the back but with the top of the head not so dark, the yellow of the under parts averaging deeper, and the whitish gular area less purely white, with more of a yellowish tinge, and more restricted in extent, not spreading over the chest. Differs from V. g. leucophrys of eastern Colombia by more greenish, less brownish back and darker cap, less brownish and more drab in tone" (Zimmer 1941: 17).

laetissimus, described as Vireosylva leucophrys laetissima Todd 1924; type locality Incachaca, Bolivia

Occurs along the east slope of the Andes from southern Peru south to central Bolivia.

Some authors have combined all taxa breeding from Canada south to Bolivia as a single species, Vireo gilvus Warbling Vireo (e.g. Zimmer 1941, Blake 1948). Most authors recognize two species in this complex, Vireo gilvus, breeding from Canada south to Mexico, and Vireo leucophrys, breeding from Mexico south to Bolivia. Phillips (1991) recognized two species in the leucophrys group, amauronotus from Mexico south to Honduras, and leucophrys from Costa Rica south to Bolivia.

There is no comprehensive phylogeny for Vireo. Starch gel electrophoresis of protein coding loci identified a clade containing leucophrys, gilvus, and philadelphicus, which was sister to a clade containing Vireo olivaceus (Red-eyed Vireo) and Vireo flavoviridis (Yellow-green Vireo) (Johnson et al. 1988). Within the gilvus clade, leucophrys was identified as sister to Vireo gilvus swainsonii, suggesting that Vireo gilvus is polyphyletic (Johnson et al. 1988). A phylogenetic analysis of mitochondrial DNA sequence data, with a smaller sample of taxa (and with no examples of leucophrys) confirmed the sister group relationship between the gilvus and olivaceus clades (Murray et al. 1994).