Warbling Vireo
Encyclopedia
The Warbling Vireo, Vireo gilvus, is a small North America
n songbird
.
Its breeding habitat is open deciduous
and mixed woods from Alaska
to Mexico
and the Florida Panhandle
. It often nests along streams. It migrate
s to Mexico
and Central America
.
Adults are 12 cm long and weigh 12 g. They are mainly olive-grey on the head and upperparts with white underparts; they have brown eyes and the front of the face is light. There is a white supercilium
. They have thick blue-grey legs and a stout bill. Western birds are generally smaller and have darker grey crowns.
They forage for insects in trees, hopping along branches and sometimes hovering. They also eat berries, especially before migration and in winter quarters, where they are – like other vireos – apparently quite fond of Gumbo-limbo seeds, though they will not venture into human-modified habitat to get them.
They make a deep cup nest suspended from a tree branch or shrub, placed relatively high in the east and lower in the west. The male helps with incubation and may sing from the nest.
Their song is a cheerful warble, similar to that of the Painted Bunting
. There are subtle differences in song between eastern and western birds, at least where the ranges meet in Alberta
. Some authorities split the eastern and western races of this species into separate species:
The Western Warbling Vireo, V. swainsonii, includes V. g. swainsonii, which breeds from southeastern Alaska and southwestern Northwest Territories
to the Sierra San Pedro Mártir
, Baja California
, and V. g. brewsteri, which breeds from southern Idaho
, Wyoming
, and Montana
to south-central Oaxaca
. These two subspecies winter in Mexico. The swainsonii group also includes V. g. victoriae, an isolated population breeding in the Sierra de la Laguna
, Baja California Sur
, and migrating to unknown wintering grounds.
The Eastern Warbling Vireo, V. gilvus, breeds from central Alberta and northern Montana
east and south through most of the United States and parts of southern Canada
, outside the range of the previous group. It winters south of the Isthmus of Tehuantepec
from south-central Chiapas
to Nicaragua
. It completes its autumn molt on the breeding grounds, while the swainsonii group completes it after leaving.
The Brown-capped Vireo
(Vireo leucophrys), resident in Central America and northern South America
, is sometimes considered conspecific with the Warbling Vireo.
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
n songbird
Songbird
A songbird is a bird belonging to the suborder Passeri of the perching birds . Another name that is sometimes seen as scientific or vernacular name is Oscines, from Latin oscen, "a songbird"...
.
Its breeding habitat is open deciduous
Deciduous
Deciduous means "falling off at maturity" or "tending to fall off", and is typically used in reference to trees or shrubs that lose their leaves seasonally, and to the shedding of other plant structures such as petals after flowering or fruit when ripe...
and mixed woods from Alaska
Alaska
Alaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...
to Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
and the Florida Panhandle
Florida Panhandle
The Florida Panhandle, an informal, unofficial term for the northwestern part of Florida, is a strip of land roughly 200 miles long and 50 to 100 miles wide , lying between Alabama on the north and the west, Georgia also on the north, and the Gulf of Mexico to the south. Its eastern boundary is...
. It often nests along streams. It migrate
Bird migration
Bird migration is the regular seasonal journey undertaken by many species of birds. Bird movements include those made in response to changes in food availability, habitat or weather. Sometimes, journeys are not termed "true migration" because they are irregular or in only one direction...
s to Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
and Central America
Central America
Central America is the central geographic region of the Americas. It is the southernmost, isthmian portion of the North American continent, which connects with South America on the southeast. When considered part of the unified continental model, it is considered a subcontinent...
.
Adults are 12 cm long and weigh 12 g. They are mainly olive-grey on the head and upperparts with white underparts; they have brown eyes and the front of the face is light. There is a white supercilium
Supercilium
The supercilium is a plumage feature found on the heads of some bird species. It is a stripe which runs from the base of the bird's beak above its eye, finishing somewhere towards the rear of the bird's head. Also known as an "eyebrow", it is distinct from the eyestripe, which is a line which runs...
. They have thick blue-grey legs and a stout bill. Western birds are generally smaller and have darker grey crowns.
They forage for insects in trees, hopping along branches and sometimes hovering. They also eat berries, especially before migration and in winter quarters, where they are – like other vireos – apparently quite fond of Gumbo-limbo seeds, though they will not venture into human-modified habitat to get them.
They make a deep cup nest suspended from a tree branch or shrub, placed relatively high in the east and lower in the west. The male helps with incubation and may sing from the nest.
Their song is a cheerful warble, similar to that of the Painted Bunting
Painted Bunting
The Painted Bunting is a species of bird in the Cardinal family, Cardinalidae, that is native to North America.-Taxonomy:...
. There are subtle differences in song between eastern and western birds, at least where the ranges meet in Alberta
Alberta
Alberta is a province of Canada. It had an estimated population of 3.7 million in 2010 making it the most populous of Canada's three prairie provinces...
. Some authorities split the eastern and western races of this species into separate species:
The Western Warbling Vireo, V. swainsonii, includes V. g. swainsonii, which breeds from southeastern Alaska and southwestern Northwest Territories
Northwest Territories
The Northwest Territories is a federal territory of Canada.Located in northern Canada, the territory borders Canada's two other territories, Yukon to the west and Nunavut to the east, and three provinces: British Columbia to the southwest, and Alberta and Saskatchewan to the south...
to the Sierra San Pedro Mártir
Sierra San Pedro Mártir
Sierra de San Pedro Mártir is a mountain range that is one of the Peninsular Ranges of the Baja California peninsula, Mexico. At , the highest peak is the Picacho del Diablo, also known as Cerro de la Encantada or Picacho la Providencia...
, Baja California
Baja California
Baja California officially Estado Libre y Soberano de Baja California is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is both the northernmost and westernmost state of Mexico. Before becoming a state in 1953, the area was known as the North...
, and V. g. brewsteri, which breeds from southern Idaho
Idaho
Idaho is a state in the Rocky Mountain area of the United States. The state's largest city and capital is Boise. Residents are called "Idahoans". Idaho was admitted to the Union on July 3, 1890, as the 43rd state....
, Wyoming
Wyoming
Wyoming is a state in the mountain region of the Western United States. The western two thirds of the state is covered mostly with the mountain ranges and rangelands in the foothills of the Eastern Rocky Mountains, while the eastern third of the state is high elevation prairie known as the High...
, and Montana
Montana
Montana is a state in the Western United States. The western third of Montana contains numerous mountain ranges. Smaller, "island ranges" are found in the central third of the state, for a total of 77 named ranges of the Rocky Mountains. This geographical fact is reflected in the state's name,...
to south-central Oaxaca
Oaxaca
Oaxaca , , officially Estado Libre y Soberano de Oaxaca is one of the 31 states which, along with the Federal District, comprise the 32 federative entities of Mexico. It is divided into 571 municipalities; of which 418 are governed by the system of customs and traditions...
. These two subspecies winter in Mexico. The swainsonii group also includes V. g. victoriae, an isolated population breeding in the Sierra de la Laguna
Sierra de la Laguna
The Sierra de la Laguna is a mountain range on the Baja California Peninsula of Mexico. It lies at the southern end of the peninsula in the state of Baja California Sur, and is the southernmost range of the Peninsular Ranges....
, Baja California Sur
Baja California Sur
Baja California Sur , is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. Before becoming a state on October 8, 1974, the area was known as the South Territory of Baja California. It has an area of , or 3.57% of the land mass of Mexico and comprises...
, and migrating to unknown wintering grounds.
The Eastern Warbling Vireo, V. gilvus, breeds from central Alberta and northern Montana
Montana
Montana is a state in the Western United States. The western third of Montana contains numerous mountain ranges. Smaller, "island ranges" are found in the central third of the state, for a total of 77 named ranges of the Rocky Mountains. This geographical fact is reflected in the state's name,...
east and south through most of the United States and parts of southern Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
, outside the range of the previous group. It winters south of the Isthmus of Tehuantepec
Isthmus of Tehuantepec
The Isthmus of Tehuantepec is an isthmus in Mexico. It represents the shortest distance between the Gulf of Mexico and the Pacific Ocean, and prior to the opening of the Panama Canal was a major shipping route known simply as the Tehuantepec Route...
from south-central Chiapas
Chiapas
Chiapas officially Estado Libre y Soberano de Chiapas is one of the 31 states that, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 118 municipalities and its capital city is Tuxtla Gutierrez. Other important cites in Chiapas include San Cristóbal de las...
to Nicaragua
Nicaragua
Nicaragua is the largest country in the Central American American isthmus, bordered by Honduras to the north and Costa Rica to the south. The country is situated between 11 and 14 degrees north of the Equator in the Northern Hemisphere, which places it entirely within the tropics. The Pacific Ocean...
. It completes its autumn molt on the breeding grounds, while the swainsonii group completes it after leaving.
The Brown-capped Vireo
Brown-capped Vireo
The Brown-capped Vireo, Vireo leucophrys, is a small passerine bird. It breeds in highlands from southern Mexico south to northwestern Bolivia. It is sometimes considered to be conspecific with the similar Warbling Vireo....
(Vireo leucophrys), resident in Central America and northern South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
, is sometimes considered conspecific with the Warbling Vireo.
External links
- Warbling Vireo Species Account - Cornell Lab of Ornithology
- Warbling Vireo - Vireo gilvus - USGS Patuxent Bird Identification InfoCenter
- Warbling Vireo Information and Photos - South Dakota Birds and Birding
- Warbling Vireo photo gallery - VIREO