Bell's vireo (''Vireo bellii'') is a

songbird A songbird is a bird belonging to the suborder Passeri of the perching birds (Passeriformes). Another name that is sometimes seen as the scientific or vernacular name is Oscines, from Latin ''oscen'', "songbird". The Passeriformes contains 5000 ...

that migrates between a breeding range in Western North America and a winter range in

Central America Central America ( es, América Central or ) is a subregion of the Americas. Its boundaries are defined as bordering the United States to the north, Colombia to the south, the Caribbean Sea to the east, and the Pacific Ocean to the west. ...

. It is dull olive-gray above and whitish below. It has a faint white eye ring and faint wing bars. This bird was named by

Audubon The National Audubon Society (Audubon; ) is an American non-profit environmental organization dedicated to conservation of birds and their habitats. Located in the United States and incorporated in 1905, Audubon is one of the oldest of such org ...

for

John Graham Bell John Graham Bell (July 12, 1812 – October 22, 1889) was an American taxidermist and collector. He traveled with John James AudubonMissouri River in the 1840s. The least Bell's vireo (''Vireo bellii pusillus'') is an

endangered An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and in ...

subspecies in

Southern California Southern California (commonly shortened to SoCal) is a geographic and cultural region that generally comprises the southern portion of the U.S. state of California. It includes the Los Angeles metropolitan area, the second most populous urban a ...

. Consideration of Bell's vireo has been a factor in several land development projects, to protect least Bell's vireo habitat. The decline of the least Bell's vireo is mostly due to a loss of riparian habitat.

Description

Measurements: * Length: 4.5-4.9 in (11.5-12.5 cm) * Weight: 0.3-0.3 oz (7.4-9.8 g) * Wingspan: 6.7-7.5 in (17-19 cm)

Behavior and ecology

Bell's vireos often use dense shrubbery including willows (''Salix spp.''), mulefat (''Baccharis glutinosa''),

California wild rose ''Rosa californica'', the California wildrose, or California rose, is a species of rose native to the U.S. states of California and Oregon and the northern part of Baja California, Mexico. The plant is native to chaparral and woodlands and the ...

(''Rosa californica''),

mugwort Mugwort is a common name for several species of aromatic flowering plants in the genus '' Artemisia.'' In Europe, mugwort most often refers to the species ''Artemisia vulgaris'', or common mugwort. In East Asia the species ''Artemisia argyi'' is ...

(''Artemisia douglasiana''),

Fremont cottonwood ''Populus fremontii'', commonly known as Frémont's cottonwood, is a cottonwood (and thus a poplar) native to riparian zones of the Southwestern United States and northern through central Mexico. It is one of three species in ''Populus'' sect. ...

(''Populus fremontii''), and

Western poison oak ''Toxicodendron diversilobum'' (syn. ''Rhus diversiloba''), commonly named Pacific poison oak or western poison oak, is a woody vine or shrub in the sumac family, Anacardiaceae. It is widely distributed in western North America, inhabiting coni ...

(''Toxicodendron diversilobum'') shrubs or vines as nesting locations. Bell's vireos make a well-

camouflage Camouflage is the use of any combination of materials, coloration, or illumination for concealment, either by making animals or objects hard to see, or by disguising them as something else. Examples include the leopard's spotted coat, the b ...

d nest but when found they will stand its ground against intruders. As with many other North American songbirds,

brown-headed cowbird The brown-headed cowbird (''Molothrus ater'') is a small, obligate brood parasitic icterid native to temperate and subtropical North America. It is a permanent resident in the southern parts of its range; northern birds migrate to the southern ...

s parasitise Bell's vireo nests, letting the vireos raise their young. Historically, the least Bell's vireo was a common to locally abundant species in lowland riparian habitat, ranging from coastal southern California through the Sacramento and San Joaquin Valleys as far north as

Red Bluff Red Bluff(s) may refer to several places in North America: Places Canada *Red Bluff, British Columbia, a community near Quesnel, British Columbia, Canada ** Red Bluff First Nation, a First Nations band government headquartered near Quesnel, ...

in Tehama County. Populations also occurred in the foothill streams of the Sierra Nevada and Coast Ranges, and in

Owens Valley Owens Valley ( Numic: ''Payahǖǖnadǖ'', meaning "place of flowing water") is an arid valley of the Owens River in eastern California in the United States. It is located to the east of the Sierra Nevada, west of the White Mountains and Iny ...

Death Valley Death Valley is a desert valley in Eastern California, in the northern Mojave Desert, bordering the Great Basin Desert. During summer, it is the Highest temperature recorded on Earth, hottest place on Earth. Death Valley's Badwater Basin is the ...

, and scattered locations in the

Mojave Desert The Mojave Desert ( ; mov, Hayikwiir Mat'aar; es, Desierto de Mojave) is a desert in the rain shadow of the Sierra Nevada mountains in the Southwestern United States. It is named for the indigenous Mojave people. It is located primarily ...

. Least Bell's vireos winter in Baja California Peninsula. Unlike during the breeding season, they are not limited in winter to willow-dominated riparian areas, but occupy a variety of habitats including mesquite scrub within arroyos, palm groves, and hedgerows bordering agricultural and residential areas. At the time of endangered species listing by the

U.S. Fish and Wildlife Service The United States Fish and Wildlife Service (USFWS or FWS) is an agency within the United States Department of the Interior dedicated to the management of fish, wildlife, and natural habitats. The mission of the agency is "working with othe ...

in 1986, it had been extirpated from most of its historic range, and numbered just 300 pairs statewide. Populations were confined to eight counties south of Santa Barbara, with the majority of birds occurring in

San Diego County San Diego County (), officially the County of San Diego, is a county in the southwestern corner of the U.S. state of California. As of the 2020 census, the population was 3,298,634, making it California's second-most populous county and the f ...

. In the decade since listing, least Bell's vireo numbers have increased six-fold, and the species is expanding into its historic range. In 1998, the population size was estimated at 2,000 pairs. Nesting least Bell's vireos have recolonized the Santa Clara River in

Ventura County Ventura County () is a County (United States), county in Southern California, the southern part of the U.S. state of California. As of the 2020 United States Census, 2020 census, the population was 843,843. The largest city is Oxnard, California ...

, where 67 pairs nested in 1998, and the

Mojave River The Mojave River is an intermittent river in the eastern San Bernardino Mountains and the Mojave Desert in San Bernardino County, California, United States. Most of its flow is underground, while its surface channels remain dry most of the time, ...

San Bernardino County San Bernardino County (), officially the County of San Bernardino, is a county located in the southern portion of the U.S. state of California, and is located within the Inland Empire area. As of the 2020 U.S. Census, the population was 2,181, ...

. The northernmost reported sighting in recent years is of a nesting pair of least Bell's vireos near Gilroy in

Santa Clara County Santa Clara County, officially the County of Santa Clara, is the sixth-most populous county in the U.S. state of California, with a population of 1,936,259, as of the 2020 census. Santa Clara County and neighboring San Benito County together f ...

in 1997. Roughly half of the current least Bell's vireo population occurs on drainages within

Marine Corps Base Camp Pendleton Marine Corps Base Camp Pendleton is the major West Coast base of the United States Marine Corps and is one of the largest Marine Corps bases in the United States. It is on the Southern California coast in San Diego County and is bordered by O ...

in San Diego County, particularly in the lower

Santa Margarita River The Santa Margarita River which with the addition of what is now Temecula Creek, was formerly known as the Temecula River, is a short intermittent river on the Pacific coast of southern California in the United States, approximately U.S. Geologi ...

References

External links

Bell's Vireo Species Account
- Cornell Lab of Ornithology

- USGS Patuxent Bird Identification InfoCenter *
Bell's Vireo synopsis

Wisconsin Department of Natural Resources

- ttp://www.fws.gov/pacific/ U.S. Fish and Wildlife Service - Pacific Region
Video of Least Bell's Vireo
* * * * {{Taxonbar, from=Q1303897

Bell's vireo Bell's vireo (''Vireo bellii'') is a songbird that migrates between a breeding range in Western North America and a winter range in Central America. It is dull olive-gray above and whitish below. It has a faint white eye ring and faint wing bar ...

Native birds of the Plains-Midwest (United States) Fauna of the Sonoran Desert Fauna of the Yuma Desert Fauna of the Chihuahuan Desert Fauna of the Lower Colorado River Valley Birds of the Rio Grande valleys Birds of Mexico