Black-throated Gray Warbler
Encyclopedia
The Black-throated Gray Warbler (Dendroica nigrescens) is a songbird
of the New World warbler
family. It is 13 cm (5 in) long and has black, grey, and white plumage. It breeds in western North America from British Columbia
to New Mexico
, and winters in Mexico and the southwestern United States. Common in its forest habitats, it does not seem to be seriously threatened by human activities, unlike many migratory warblers.
and Blackpoll Warbler
s, which although black have entirely different patterns.
It is typically 13 cm (5 in) long, weighing 8.4 g (0.29 oz). Wing lengths are 5.6–6.9 cm (2.2–2.7 in), tail lengths 4.7–5.5 cm (1.9–2.2 in), bill lengths 8.4–9.6 cm (3.3–3.8 in), and tarsus
lengths 1.66–1.88 cm (0.65–0.74 in), with females slightly smaller than males.
This bird gives a sharp tup or thick call, like that of Townsend's Warbler
but flat and unmusical, as well as a high see flight call. The male's song is a series of buzzy notes, with the earlier notes doubled and the next to last note high. This song has three variations, including a quiet "soft song" given by the males while following females gathering material for a nest.
from a specimen collected near today's Portland, Oregon
. It was known to the Chinook inhabitants of the northwest coast, who called it Ah Kah a qual. Townsend described the species as Sylvia nigrescens, placing it with the other New World warlblers and the unrelated Old World warbler
s in the genus Sylvia. It is now placed in the genus Dendroica
, along with about thirty other species. Within this genus, it is part of a group with black throats and yellow face markings that includes the Hermit Warbler
and Townsend's Warbler
. Among these species, it is usually considered an early offshoot, but genetic studies suggest a close relation to Grace's Warbler
.
Of these relatives, Townsend's Warbler and the Hermit Warbler overlap with the Black-throated Gray Warbler, but inhabit different habitats. While these two species hybridize commonly, records of hybridization with the Black-throated Gray Warbler are uncommon.
There are two subspecies
, which are highly similar in appearance but genetically distinct. The nominate subspecies D. n. nigrescens occurs on the Pacific coastal region from British Columbia to northern California, while D. n. halseii, described by Giraud in 1841, occupies the remainder of its range. D. n. halseii birds are slightly larger and more gray in their upperparts.
along the Pacific coast, and east to New Mexico and southern Montana. It winters mostly in Mexico, from southern Baja California
to Oaxaca
state. It has spread into parts of Wyoming and Montana only recently, as Juniperus osteosperma
has expanded its range due to a warming climate. Vagrants
have been recorded across eastern North America. It breeds in open coniferous and mixed forest
with a brushy understory, in dry open oak forests, and in chaparral
and other scrubland. It is particularly associated with pinyon pine
s, juniper
s, and oaks. It migrates to the south late in the fall, returning north in mid-spring. While migrating, it forages in any woodland or scrub it passes through. In its wintering grounds, it occurs in dry woodland and tall scrub. Though its status is not well known, it does not appear to be seriously threatened by habitat destruction
or other human activities, unlike many migratory warblers. It is a fairly common bird, among the most common in some localities. Because of its commonality, it is assessed as Least Concern
on the IUCN Red List
.
said "almost no information is available". It forages, often in flocks with other species. It feeds on insects gleaned
on low branches, especially caterpillar
s.
The nest is usually placed on a horizontal tree branch or in a shrub, a few metres above the ground. The nest is an open cup constructed of grass stalks and other fibres, and lined with feathers and hair. The female lays 3–5 pinkish eggs with brown dots from May to July. Incubation and fledgeing periods are not recorded. It has been recorded giving a distraction display
, pretending to be injured to distract predators from its nest. Both parents feed the young, though the female may do so more frequently.
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"...
of the New World warbler
New World warbler
The New World warblers or wood-warblers are a group of small, often colorful, passerine birds restricted to the New World. They are not related to the Old World warblers or the Australian warblers....
family. It is 13 cm (5 in) long and has black, grey, and white plumage. It breeds in western North America from British Columbia
British Columbia
British Columbia is the westernmost of Canada's provinces and is known for its natural beauty, as reflected in its Latin motto, Splendor sine occasu . Its name was chosen by Queen Victoria in 1858...
to New Mexico
New Mexico
New Mexico is a state located in the southwest and western regions of the United States. New Mexico is also usually considered one of the Mountain States. With a population density of 16 per square mile, New Mexico is the sixth-most sparsely inhabited U.S...
, and winters in Mexico and the southwestern United States. Common in its forest habitats, it does not seem to be seriously threatened by human activities, unlike many migratory warblers.
Description
The Black-throated Gray Warbler has mostly black, gray, and white plumage, which is soft, lacking gloss. With its striping and the small yellow spot between its eye and bill, it is a distinctive bird. The sexes differ slightly, both having gray upperparts with black streaks, and white underparts with black streaks on the flanks. The adult male is striped on its head, with a black crown, throat, and stripe below the eye, and white around its chin and above its eye. The adult female has more dingy plumage on its head, with a white throat and dark gray cheeks. The most similar birds to the Black-throated Gray Warbler are the Black-and-whiteBlack-and-white Warbler
The Black-and-white Warbler is a small New World warbler. It breeds in northern and eastern North America from southern Canada to Florida....
and Blackpoll Warbler
Blackpoll Warbler
The Blackpoll Warbler, Dendroica striata , is a New World warbler. Breeding males are mostly black and white. They have a prominent black cap, white cheeks and white wing bars. The Blackpoll breeds in northern North America, from Alaska, through most of Canada, and into the Great Lakes region and...
s, which although black have entirely different patterns.
It is typically 13 cm (5 in) long, weighing 8.4 g (0.29 oz). Wing lengths are 5.6–6.9 cm (2.2–2.7 in), tail lengths 4.7–5.5 cm (1.9–2.2 in), bill lengths 8.4–9.6 cm (3.3–3.8 in), and tarsus
Tarsus (skeleton)
In tetrapods, the tarsus is a cluster of articulating bones in each foot situated between the lower end of tibia and fibula of the lower leg and the metatarsus. In the foot the tarsus articulates with the bones of the metatarsus, which in turn articulate with the bones of the individual toes...
lengths 1.66–1.88 cm (0.65–0.74 in), with females slightly smaller than males.
This bird gives a sharp tup or thick call, like that of Townsend's Warbler
Townsend's Warbler
The Townsend's Warbler, Dendroica townsendi, is a small songbird of the New World warbler family.These birds have a yellow face with a black stripe across their cheeks, a thin pointed bill, white wing bars, olive upperparts with black streaks on their backs and flanks, and a white belly...
but flat and unmusical, as well as a high see flight call. The male's song is a series of buzzy notes, with the earlier notes doubled and the next to last note high. This song has three variations, including a quiet "soft song" given by the males while following females gathering material for a nest.
Taxonomy
The Black-throated Grey Warbler was first described by John Kirk TownsendJohn Kirk Townsend
John Kirk Townsend was an American naturalist, ornithologist and collector.Townsend was born in Philadelphia and trained as a physician and pharmacist. He developed an interest in natural history in general and bird collecting in particular...
from a specimen collected near today's Portland, Oregon
Portland, Oregon
Portland is a city located in the Pacific Northwest, near the confluence of the Willamette and Columbia rivers in the U.S. state of Oregon. As of the 2010 Census, it had a population of 583,776, making it the 29th most populous city in the United States...
. It was known to the Chinook inhabitants of the northwest coast, who called it Ah Kah a qual. Townsend described the species as Sylvia nigrescens, placing it with the other New World warlblers and the unrelated Old World warbler
Old World warbler
The "Old World Warblers" is the name used to describe a large group of birds formerly grouped together in the bird family Sylviidae. The family held over 400 species in over 70 genera, and were the source of much taxonomic confusion. Two families were split out initially, the cisticolas into...
s in the genus Sylvia. It is now placed in the genus Dendroica
Dendroica
Dendroica is a genus of birds of the New World Warbler family Parulidae. It contains 29 species. The males in breeding plumage are often highly colorful...
, along with about thirty other species. Within this genus, it is part of a group with black throats and yellow face markings that includes the Hermit Warbler
Hermit Warbler
The Hermit Warbler, Dendroica occidentalis, is a small perching bird. It is a species of New World warbler.Mature Hermit Warblers normally grow to be 4½ to 5 inches long. Hermit Warblers are dark gray in coloration on top, and white below, and their flanks are streaked with black. The wings...
and Townsend's Warbler
Townsend's Warbler
The Townsend's Warbler, Dendroica townsendi, is a small songbird of the New World warbler family.These birds have a yellow face with a black stripe across their cheeks, a thin pointed bill, white wing bars, olive upperparts with black streaks on their backs and flanks, and a white belly...
. Among these species, it is usually considered an early offshoot, but genetic studies suggest a close relation to Grace's Warbler
Grace's Warbler
Grace's Warbler, Dendroica graciae, is a small perching bird and a species of New World warbler.Grace's Warbler was discovered by Dr. Elliott Coues in the Rocky Mountains in 1864...
.
Of these relatives, Townsend's Warbler and the Hermit Warbler overlap with the Black-throated Gray Warbler, but inhabit different habitats. While these two species hybridize commonly, records of hybridization with the Black-throated Gray Warbler are uncommon.
There are two subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
, which are highly similar in appearance but genetically distinct. The nominate subspecies D. n. nigrescens occurs on the Pacific coastal region from British Columbia to northern California, while D. n. halseii, described by Giraud in 1841, occupies the remainder of its range. D. n. halseii birds are slightly larger and more gray in their upperparts.
Distribution and habitat
The Black-throated Gray Warbler breeds in western North America, its range extending from southwestern British ColumbiaBritish Columbia
British Columbia is the westernmost of Canada's provinces and is known for its natural beauty, as reflected in its Latin motto, Splendor sine occasu . Its name was chosen by Queen Victoria in 1858...
along the Pacific coast, and east to New Mexico and southern Montana. It winters mostly in Mexico, from southern 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...
to 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...
state. It has spread into parts of Wyoming and Montana only recently, as Juniperus osteosperma
Juniperus osteosperma
Juniperus osteosperma is a shrub or small tree reaching 3-6 m tall. It is native to the southwestern United States, in Utah, Nevada, Arizona, western New Mexico, western Colorado, Wyoming, southern Montana, southern Idaho and eastern California...
has expanded its range due to a warming climate. Vagrants
Vagrancy (biology)
Vagrancy is a phenomenon in biology whereby individual animals appear well outside their normal range; individual animals which exhibit vagrancy are known as vagrants. The term accidental is sometimes also used...
have been recorded across eastern North America. It breeds in open coniferous and mixed forest
Temperate broadleaf and mixed forests
Mixed forests are a temperate and humid biome. The typical structure of these forests includes four layers. The uppermost layer is the canopy composed of tall mature trees ranging from 33 to 66 m high. Below the canopy is the three-layered, shade-tolerant understory that is roughly 9 to...
with a brushy understory, in dry open oak forests, and in chaparral
Chaparral
Chaparral is a shrubland or heathland plant community found primarily in the U.S. state of California and in the northern portion of the Baja California peninsula, Mexico...
and other scrubland. It is particularly associated with pinyon pine
Pinyon pine
The pinyon pine group grows in the southwestern United States and in Mexico. The trees yield edible pinyon nuts, which were a staple of the Native Americans, and are still widely eaten...
s, juniper
Juniper
Junipers are coniferous plants in the genus Juniperus of the cypress family Cupressaceae. Depending on taxonomic viewpoint, there are between 50-67 species of juniper, widely distributed throughout the northern hemisphere, from the Arctic, south to tropical Africa in the Old World, and to the...
s, and oaks. It migrates to the south late in the fall, returning north in mid-spring. While migrating, it forages in any woodland or scrub it passes through. In its wintering grounds, it occurs in dry woodland and tall scrub. Though its status is not well known, it does not appear to be seriously threatened by habitat destruction
Habitat destruction
Habitat destruction is the process in which natural habitat is rendered functionally unable to support the species present. In this process, the organisms that previously used the site are displaced or destroyed, reducing biodiversity. Habitat destruction by human activity mainly for the purpose of...
or other human activities, unlike many migratory warblers. It is a fairly common bird, among the most common in some localities. Because of its commonality, it is assessed as Least Concern
Least Concern
Least Concern is an IUCN category assigned to extant taxon or lower taxa which have been evaluated but do not qualify for any other category. As such they do not qualify as threatened, Near Threatened, or Conservation Dependent...
on the IUCN Red List
IUCN Red List
The IUCN Red List of Threatened Species , founded in 1963, is the world's most comprehensive inventory of the global conservation status of biological species. The International Union for Conservation of Nature is the world's main authority on the conservation status of species...
.
Behaviour
The Black-throated Gray Warbler is usually approachable, and can easily be observed while foraging. Despite this, it is poorly known, especially in its breeding behaviour, of which Birds of North AmericaBirds of North America
Birds of North America is a comprehensive encyclopedia with substantial articles about each individual bird species.It was first published as a series of 716 printed booklets, prepared by over 5000 individual researchers, and made available in no particular order from 1992 through 2003...
said "almost no information is available". It forages, often in flocks with other species. It feeds on insects gleaned
Gleaning (birds)
Gleaning is a term for a feeding strategy by birds in which they catch invertebrate prey, mainly arthropods, by plucking them from foliage or the ground, from crevices such as rock faces and under the eaves of houses, or even, as in the case of ticks and lice, from living animals. This behavior is...
on low branches, especially caterpillar
Caterpillar
Caterpillars are the larval form of members of the order Lepidoptera . They are mostly herbivorous in food habit, although some species are insectivorous. Caterpillars are voracious feeders and many of them are considered to be pests in agriculture...
s.
The nest is usually placed on a horizontal tree branch or in a shrub, a few metres above the ground. The nest is an open cup constructed of grass stalks and other fibres, and lined with feathers and hair. The female lays 3–5 pinkish eggs with brown dots from May to July. Incubation and fledgeing periods are not recorded. It has been recorded giving a distraction display
Distraction display
Distraction displays, also known as deflection display, diversionary display or paratrepsis, are anti-predator behaviours used to attract the attention of an enemy away from an object, typically the nest or young, that is being protected. They are particularly well known in birds but noted also in...
, pretending to be injured to distract predators from its nest. Both parents feed the young, though the female may do so more frequently.
External links
- Black-throated Gray Warbler at All About Birds
- Black-throated Gray Warbler at the Internet Bird Collection