Red warbler | |
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Cardellina rubra melanauris Sinaloa, Mexico | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Aves |
Order: | Passeriformes |
Family: | Parulidae |
Genus: | Cardellina |
Species: | C. rubra |
Binomial name | |
Cardellina rubra (Swainson, 1827) | |
Range of the red warbler Blue = ssp. melanauris green = ssp. rubra brown = ssp. rowleyi | |
Synonyms | |
The red warbler (Cardellina rubra) is a small passerine bird of the New World warbler family Parulidae endemic to the highlands of Mexico, north of the Isthmus of Tehuantepec. It is closely related to, and forms a superspecies with, the pink-headed warbler of southern Mexico and Guatemala. There are three subspecies, found in disjunct populations, which differ in the color of their ear patch and in the brightness and tone of their body plumage. The adult is bright red, with a white or gray ear patch, depending on the subspecies; young birds are pinkish-brown, with a whitish ear patch and two pale wingbars .
Breeding typically occurs between February and May. The female lays three or four eggs in a domed nest, which she builds on the ground. Though she alone incubates the eggs, both sexes feed the young and remove fecal sacs from the nest. The young fledge within 10–11 days of hatching. The red warbler is an insectivore, gleaning primarily in understory shrubs. Although this bird is considered to be a least-concern species according to the International Union for Conservation of Nature (IUCN), its numbers are thought to be declining due to habitat destruction.
English jeweler and naturalist William Bullock and his son traveled to Mexico soon after its independence, spending six months in 1823 collecting archaeological artifacts and many bird and fish species new to science. [4] The bird specimens were given to naturalist William John Swainson, their countryman, to formally describe, which he did in 1827. Among these was the red warbler, which was assigned to the genus Setophaga , as Setophaga rubra. [2] Over the next half century, other authorities moved it to Cardellina , with the red-faced warbler, and to the widespread tropical warbler genus Basileuterus , as well as to the Old World warbler genus Sylvia and the Old World tit genus Parus . In 1873, English naturalists Philip Lutley Sclater and Osbert Salvin moved the species to the genus Ergaticus , where it remained for more than a century. [3]
The red warbler forms a superspecies with the pink-headed warbler of Chiapas and Guatemala. Despite their disjunct ranges and considerably different plumages, the two have sometimes been considered conspecific. [5] Conversely, it has also been suggested that the red warbler should be split into a northern gray-eared species (C. melanauris) and a southern white-eared species (C. rubra). [6] A comprehensive 2010 paper by Irby Lovette and colleagues analyzing mitochondrial and nuclear DNA of the New World warblers found that the red and pink-headed warblers are each other's closest relative and that their common ancestor diverged from a lineage that gave rise to the red-faced warbler. The authors recommended moving the red and pink-headed warblers to the genus Cardellina, [7] a suggestion which has been adopted by the International Ornithologists' Union (IOC). [8]
There are three subspecies, which differ slightly in appearance: [5]
"Red warbler" has been designated the official name by the IOC. [8] It is a straightforward reference to its color. The genus name Cardellina is the diminutive of the Italian cardella, a regional name for the European goldfinch, [14] while its specific name, rubra, is Latin for "red". [15]
The red warbler is a small passerine, measuring 12.5–13.5 cm (4.9–5.3 in) in length, [9] [nb 1] and weighing from 7.6 to 8.7 g (0.27 to 0.31 oz). [5] As an adult, it is red overall, with either a white or dark gray (depending on the subspecies) auricular patch on each side of its head. Its wings and tail are slightly darker, dusky red, [17] and edged in pinkish-red. [9] Its legs are a dull red-brown, and its thin bill is pinkish-gray [18] with a dark tip. [9] The iris is dark brown to blackish. Plumage varies little between the sexes, although the female tends to be a little duller or more orange-tinged. Adult pairs separate and molt fully from August, after the breeding season. [18]
The adult red warbler is hard to confuse with any other bird species in its range; the scarlet tanager and summer tanager have similar mostly-red plumage but are larger with thick conical bills. [18]
As a juvenile, the red warbler is pinkish-brown with a whitish auricular patch. Its darker wings and tail show pinkish-cinnamon edges, with two paler wingbars on the former. [9]
The red warbler has several common calls, including a high, thin tsii and a stronger pseet. Its song is a mix of short trills and richer warbles, interspersed with high-pitched chips. [19] Unlike other species in the same habitat zone, it tends to sing only during bright morning hours during the breeding season. It does not sing – and even its calling frequency decreases – in cloudy weather, regardless of season. [20]
Endemic to the highlands of Mexico north of the Isthmus of Tehuantepec, the red warbler has three disjunct populations that correspond to the three subspecies: from southwestern Chihuahua to northern Nayarit, from southern Jalisco and southern Hidalgo to Oaxaca, and from Guerrero into southern Oaxaca in the Sierra Madre del Sur mountains. [5] [9] It is fairly common to common in the country's interior and on adjacent slopes, where it occurs at elevations ranging from 1,800 to 3,900 metres (5,900 to 12,800 ft) above sea level; it does not occur along either coast. [9] [21] It is an altitudinal migrant, moving from higher humid or semi-humid pine, pine-oak and fir forests in the breeding season to lower elevations, often in oak forests, in the winter. [5] [9] It is among the most common of the small birds in its woodland habitat, second only to the golden-crowned kinglet in fir forests in one study [22] and the third most common warbler in oak-conifer woodlands in another. [23]
Though the species was reported to have been collected in Texas in the late 19th century, the record's location was not widely believed, and there is no strong evidence that it ever occurred there. [24] It has strayed as far north as southeastern Arizona, where a bird was found on Mount Lemmon in 2018. [25]
Though it occasionally joins mixed-species flocks, the red warbler is more typically found alone or in pairs. [9] Youngsters probably choose mates in the autumn of their first year, and pairs remain together year-round, [5] except during severe weather and during post-breeding molt. [20]
The red warbler breeds primarily in early spring, from February until May, [5] though at least one nest containing young has been found as late as the end of June. [26] By late February, the male establishes a territory that averages about 40 square metres, defending it with song. Other males may intrude by silently flying in at a height of around 3 m (10 ft) and back to their own territory. Deep incursions result in combat, after which the interloper usually leaves. Beginning in mid-March, the male courts the female by chasing her through the undergrowth. [20] The pair then perch together while the male sings and the female calls softly. [27] The female alone builds the nest, [28] a task which typically takes 4–6 days. [20] She chooses a sunlit area, such as an area of windfall, the brushy edge of a trail or water course, [20] or a small clearing, [26] for its location. Tightly woven of plant material, the nest is hidden in ground vegetation and anchored to the stalks of surrounding vegetation. [29] The nest, which is usually oven-shaped with a side or upward-facing entrance, [9] measures roughly 15 cm (6 in) wide by 18 cm (7 in) long by 11 cm (4.5 in) high. [29] Bulky and untidy on the outside, it is typically constructed primarily of dead pine needles and dead grass, though gray lichens, green moss, dead leaves, [28] shreds of bark and tips of fern fronds are also used; [20] most of these materials are gathered from the ground close to the nest, though some is picked from low branches or further away. [28] A few nests are only cups, lacking the roof of the more typical structures. [20] Inside, the nest is tidy and compact, [28] lined with fine grasses and plant fluff, [29] which is generally gathered some distance from the nest. [28]
Early in the breeding season, there may be a gap of as many as 11 days between the completion of the nest and the laying of the first egg. Later in the season, this time decreases so that the first egg is laid as soon as the nest is ready. [20] The female normally lays three eggs, though clutches of up to four have been recorded. [9] The eggs, which are variously described as pale pink with evenly distributed brown spots [28] or white with cinnamon and rust spots densely ringing the larger end of the egg, [20] measure 16–17 mm (0.63–0.67 in) by 13 mm (0.51 in) [28] and weigh 1–1.4 g (0.035–0.049 oz). The female alone incubates the eggs for 16 days; the male does not even approach the nest until several days after the eggs hatch. She sits facing the back wall of the nest, with her head and body sheltered by its roof and her tail sticking out the opening. She sits tight at the approach of danger, typically not flying until a potential predator actually makes contact with the nest. [20]
Both adults feed the nestlings and remove fecal sacs, [26] though the female removes far more than the male does. [20] The parents move deceptively when approaching the nest, foraging – or pretending to forage – in nearby vegetation. They stay only a few seconds in any one spot, including at the nest, making it more difficult for a predator to locate the young. Nestlings make a rapid, high-pitched peeping call as an adult approaches carrying food. [26] They fledge within 10–11 days of hatching. Young birds are fully grown three weeks after fledging, upon which time they are driven off by their parents. [20]
The red warbler is an insectivore. It gleans primarily in understory shrubs at low to middle levels, [5] moving slowly and deliberately through more open areas of the vegetation, [30] and feeding with quick jabs into cracks in bark and pine needle clusters. [20] It sometimes hovers briefly to feed at pine needle clusters, a foraging technique known as "hover gleaning". [20] Though it lacks any obvious adaptations for climbing, it regularly does so in its search for prey items on bark and epiphytes on branches, [31] often hanging head-down as it probes. [20] In areas of deciduous growth, it typically flycatches, making brief aerial sorties from a perch in pursuit of flying insects. While it seldom associates with mixed-species flocks, it often feeds alongside other birds with no signs of conflict, displaying no hostility towards other species—such as the slate-throated whitestart (Myioborus miniatus)—with which it competes. It has been observed chasing off a flycatcher of the genus Empidonax . Its foraging area is quite small, often amounting to only a few dozen square meters (several hundred square feet) per day. Late in the afternoon, its rate of foraging declines, and it rests, often taking brief naps, in the forest understory. Though it does not generally feed after sunset, it may do so to take advantage of transient food sources, such as hatching Neuroptera. [20]
The red warbler is presumably hunted by small hawks such as the sharp-shinned hawk, and its nest raided by wrens, rodents, raccoons, feral cats and snakes. [27] Isospora cardellinae is a protozoan species that has been isolated from a red warbler from Nevado de Toluca National Park, Mexico. It is a parasite that lives in cells in the villi of the bird's small intestine. [32]
In the 16th century, Friar Bernardino de Sahagún had reported that a red bird matching the description of the red warbler was regarded as inedible by the Aztecs. Researchers Patricia Escalante and John W. Daly isolated two alkaloids in preliminary investigations of the feathers. [33] The presence of these alkaloids render the bird unpalatable; humans find it inedible. [34]
The red warbler is currently rated as a species of least concern by the International Union for Conservation of Nature. Though there is evidence that its numbers are decreasing, the decline has not been precipitous (that is, less than a 30% decline over ten years or three generations), and the population remains quite large, estimates ranging from 50,000 to 499,999 birds. [1] The forested areas in which it occurs include some of the most threatened habitats in Mexico; logging, agricultural expansion, firewood gathering, road building, tourist development, overgrazing and intensive urbanization are among the many things contributing to the destruction of the forests. [35] There is some evidence that selective logging in pine forests may actually favor this species, which prefers more open, sunlit areas in which to breed. [20]
The American bushtit or simply bushtit is a social songbird belonging to the genus Psaltriparus. It is one of the smallest passerines in North America and it is the only species in the family Aegithalidae that is found in United States; the other seven species are found in Eurasia.
The golden-crowned kinglet is a very small songbird in the family Regulidae that lives throughout much of North America.
The yellow-rumped warbler is a regular North American bird species that can be commonly observed all across the continent. Its extensive distribution range connects both the Pacific and Atlantic coasts of the U.S. as well as Canada and Central America, with the population concentrating in the continent's northern parts during the breeding season and migrating southwards to southern North and Central America in Winter. The species generally prefers coniferous forests or mixed coniferous-deciduous forests as its breeding habitat, while during the winter it can be found inhabiting more open areas such as shrublands that offer food resources. The diet of the yellow-rumped warbler is based primarily on insects, though the species does eat fruits such as juniper berries as well, especially in winter.
The magnolia warbler is a member of the wood warbler family Parulidae.
The black-and-white warbler is a species of New World warbler, and the only member of its genus, Mniotilta. It breeds in northern and eastern North America and winters in Florida, Central America, and the West Indies down to Peru. This species is a very rare vagrant to western Europe.
Wilson's warbler is a small New World warbler. It is greenish above and yellow below, with rounded wings and a long, slim tail. The male has a black crown patch; depending on the subspecies, that mark is reduced or absent in the female. It breeds across Canada and south through the western United States, and winters from Mexico south through much of Central America. It is a very rare vagrant to western Europe.
The hooded warbler is a New World warbler. It breeds in eastern North America across the eastern United States and into southernmost Canada (Ontario). It is migratory, wintering in Central America and the West Indies. Hooded warblers are very rare vagrants to western Europe.
The cerulean warbler is a small songbird in the family Parulidae. It is a long-distance migrant, breeding in eastern North American hardwood forests. In the non-breeding season, it winters on the eastern slope of the Andes in South America, preferring subtropical forests.
The Canada warbler is a small boreal songbird of the New World warbler family (Parulidae). It summers in Canada and northeastern United States and winters in northern South America.
The Nashville warbler is a small songbird in the New World warbler family, found in North and Central America. It breeds in parts of the northern and western United States and southern Canada, and migrates to winter in southern California and Texas, Mexico, and the north of Central America. It has a gray head and a green back, and its underparts are yellow and white.
The black-throated gray warbler or black-throated grey warbler is a passerine bird of the New World warbler family Parulidae. It is 13 cm (5.1 in) long and has gray and white plumage with black markings. The male has the bold black throat of its name, and black stripes on its head, as well as black streaks on its flanks; the female is a paler version of the male, with a white throat and less distinct black markings on the flanks and wings. It breeds in western North America from British Columbia to New Mexico, and winters in Mexico and the southwestern United States. The habitats it prefers are coniferous and mixed forests and scrubland, especially those with pinyon pines, junipers, sagebrush, and oaks. Its nest is an open cup of plant fibers lined with feathers, built a few metres from the ground in the branches of a tree or shrub. Three to five eggs are laid, and young are fed by both parents. Common in its breeding range, it does not seem to be seriously threatened by human activities, unlike many migratory warblers.
Townsend's warbler is a small songbird of the New World warbler family.
The painted redstart or painted whitestart is a species of New World warbler found in mountainous areas across inland Central America. They are among the largest warblers, reaching the length of 6 inches (150 mm), tail included. Adult birds have glossy black plumage, with white strips on the wing and a bright red belly. Female and male birds have similar appearance. Female painted redstarts have a rare feature of being as good singers as the males.
Grace's warbler is a small New World warbler that specializes in pine woods.
The pink-headed warbler is a small passerine bird found in the southwestern highlands of Guatemala and the central and southeastern highlands of the Mexican state of Chiapas. The adult is primarily red, with a silvery-pink head and chest. It is a fairly common to common resident of humid to semi-humid pine-oak, pine-evergreen and evergreen forest and edge, at altitudes ranging from 1,800–3,500 m (5,900–11,500 ft) above sea level.
The grey-throated chat is a species of bird in the family Cardinalidae, the cardinals or cardinal grosbeaks. It is found in Belize, Guatemala, and Mexico.
The white-striped woodcreeper is a species of bird in the subfamily Dendrocolaptinae of the ovenbird family Furnariidae. It is endemic to Mexico.
The green-tailed warbler, also known as the green-tailed ground-tanager, is a species of bird of the family Phaenicophilidae, the Hispaniolan tanagers. It is endemic to the island of Hispaniola which is shared by Haiti and the Dominican Republic.
The white-winged warbler, also called the white-winged ground-warbler or Hispaniolan highland-tanager, is a Vulnerable species of bird of the family Phaenicophilidae, the Hispaniolan tanagers. It is endemic to the island of Hispaniola which is shared by Haiti and the Dominican Republic.
Ergaticus was a genus of New World warblers — small passerine birds found only in the Americas. It was described by Spencer Fullerton Baird in 1865 and later subsumed into Cardellina in 2011. The name is the Latinized version of the Ancient Greek ergatikos, meaning "willing or able to work". The genus contains two sister species: the red warbler, which is endemic to the Mexican highlands north of the Isthmus of Tehuantepec, and the pink-headed warbler, which is found south of the Isthmus, from the highlands of Chiapas, Mexico down into Guatemala. Though they are separated by geography and differ considerably in plumage, the two have sometimes been considered to be conspecific.