Hutton's vireo
Hutton's vireo is a small songbird in the family Vireonidae, the vireos, greenlets, and shrike-babblers. It is found from southwestern Canada to Guatemala.
Taxonomy and systematics
Hutton's vireo was originally described in 1851 as Vireo huttoni, its current binomial. The bird's specific epithet and later its English name commemorate William Rich Hutton, "a zealous and talented young naturalist".The taxonomy of Hutton's vireo is unsettled. The IOC and AviList assign it these 12 subspecies:
- V. h. obscurus Alfred W. Anthony, 1891
- V. h. parkesi Amadeo M. Rea, 1991
- V. h. sierrae Rea, 1991
- V. h. huttoni Cassin, 1851
- V. h. oberholseri Lois B. Bishop, 1905
- V. h. unitti Rea, 1991
- V. h. cognatus Ridgway, 1903
- V. h. stephensi Brewster, 1882
- V. h. carolinae Herbert W. Brandt, 1938
- V. h. pacificus Phillips, AR, 1966
- V. h. mexicanus Ridgway, 1903
- V. h. vulcani Griscom, 1930
The more northerly coastal subspecies V. h. obscurus through V. h. cognatus in the list above are separated by a wide expanse of desert from the other five subspecies and the two groups differ significantly in their genetics as well. Some authors have suggested that the two groups should be recognized as separate species. Clements recognizes the differences within the species by calling them the "Pacific huttoni" and "interior stephensi" groups.
This article follows the 12-subspecies model.
Description
Hutton's vireo is long and weighs about. The sexes have the same plumage. Adults of the nominate subspecies V. h. huttoni have an olive crown and nape, pale lores, a wide, broken, pale whitish eye-ring, and pale olive ear coverts. Their upperparts are olive that becomes greener on the rump. Their wing coverts are dusky olive with wide pale yellowish olive tips that show as two wing bars. Their remiges and rectrices are dusky brownish to blackish with pale yellowish olive edges on the outer webs. Their underparts are yellowish white with a pale buff to grayish olive wash.The plumages of the Hutton's vireo subspecies generally follow Gloger's Rule, with the palest, most yellowish birds are in the north and gradually becoming grayer and darker to the south. The subspecies other than the nominate differ from it and each other thus:
- V. h. obscurus: bright greenish olive crown, nape, and back, yellowish eye-ring and wing bars, olive-buff flanks, and buff-yellow underparts
- V. h. parkesi: similar to obscurus with more yellowish upperparts, a brighter rump, and brighter yellow underparts
- V. h. sierrae: pale grayish crown and nape, pale yellow-green back, and yellowish white underparts
- V. h. oberholseri: slate-gray crown and nape, pale olive edges on rectrices, and whiter underparts than nominate
- V. h. unitti: dusky olive back, grayish wing bars, olive edges on rectrices, and olive-gray flanks
- V. h. cognatus: grayish olive back and pale buff-yellow underparts
- V. h. stephensi: paler overall than nominate with olive gray back, yellowish white eye-ring, wing bars, and rectrix edges, and olive-buff underparts
- V. h. carolinae: similar to stephensi but darker and greener crown, nape, and back
- V. h. pacificus: darker in general than stephensi but richer more yellowish crown, rump, and rectrix edges
- V. h. mexicanus: darkest subspecies; olive-gray to olive-brown back; underparts darker on breast, sides, and flanks than on belly
- V. h. vulcani: similar to mexicanus but richer colored overall with greener crown
Distribution and habitat
Hutton's vireo has a disjunct distribution. The "Pacific" subspecies' ranges are contiguous except for V. h. cognatus; the "interior" subspecies have several discrete ranges. The subspecies are found thus:- V. h. obscurus: south western British Columbia including Vancouver Island south through western Washington and Oregon into northwestern California
- V. h. parkesi: northwestern and western California south to Marin County
- V. h. sierrae: eastern California's northern and central Sierra Nevada
- V. h. huttoni: from Monterey County, California south coastally into northwestern Baja California; Santa Rosa and Santa Cruz islands
- V. h. oberholseri: California Coast Ranges from Monterey County south into southern California
- V. h. unitti: Santa Catalina Island
- V. h. cognatus: southern Baja California
- V. h. stephensi: Sierra Madre Occidental from central and eastern Arizona and southwestern New Mexico south to Zacatecas state in central Mexico
- V. h. carolinae: from southwestern Texas south in eastern Mexico to Zacatecas and northwestern Hidalgo
- V. h. pacificus: southwestern Mexico from Nayarit south to southwestern Jalisco
- V. h. mexicanus: southern Mexico between central Mexico state and northern Oaxaca
- V. h. vulcani: southwestern Guatemala
Hutton's vireo inhabits a variety of landscapes in the subtropical and temperate zones. The "Pacific" subspecies are mostly found in evergreen forest of both conifer and live oak types. In the U. S. the "inland" subspecies are found in pine, pine-oak, and pine-oak-juniper woodlands and in Mexico in these same associations and also fir forest. In Guatemala V. h. vulcani inhabits pine-oak forest and pine savanna. In elevation Hutton's vireo ranges from sea level to about in British Colombia. In Washington, Oregon, and California it ranges from sea level to. In Mexico and Guatemala the "inland" subspecies range mostly between.