Northern mockingbird | |
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An adult in New York City | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Aves |
Order: | Passeriformes |
Family: | Mimidae |
Genus: | Mimus |
Species: | M. polyglottos |
Binomial name | |
Mimus polyglottos | |
Northern mockingbird range Breeding range Year-round range | |
Synonyms | |
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The northern mockingbird (Mimus polyglottos) is a mockingbird commonly found in North America, of the family Mimidae. The species is also found in some parts of the Caribbean, as well as on the Hawaiian Islands. It is typically a permanent resident across much of its range, but northern mockingbirds may move farther south during inclement weather or prior to the onset of winter. The northern mockingbird has gray to brown upper feathers and a paler belly. Its tail and wings have white patches which are visible in flight. [2]
The species is known for its ability to mimic bird calls and other types of sound, including artificial and electronic noises. Studies have shown its ability to identify individual humans and treat them differently based on learned threat assessments. [3] It is an omnivore and consumes fruit, invertebrates, and small vertebrates. It is often found in open areas, open woodlands and forest edges, and is quite common in urbanized areas. The species breeds from southeastern Canada throughout the United States to the Greater Antilles. It is listed as a species of least concern by the International Union for Conservation of Nature.
The mockingbird is influential in United States culture, being the state bird of five states, appearing in book titles, songs and lullabies, and making other appearances in popular culture.
Swedish zoologist Carl Linnaeus first described this species in his Systema Naturae in 1758 as a species of thrush, Turdus polyglottos. [4] Its current genus name, Mimus, is Latin for "mimic" and the specific polyglottos, is from Ancient Greek poluglottos, "harmonious", from polus, "many", and glossa, "tongue", [5] representing its outstanding ability to mimic various sounds. [6] The northern mockingbird is considered to be conspecific with the tropical mockingbird (Mimus gilvus). [7]
This species is categorized as the northern mockingbird as the closest living relative to M. gilvus. [8] [9]
There are three recognized subspecies for the northern mockingbird. [10] [11] There have been proposed races from the Bahamas and Haiti placed under the orpheus section. [11]
The northern mockingbird is a medium-sized mimid that has long legs and tail. [12] Males and females look alike. [13] Its upper parts are colored gray, while its underparts have a white or whitish-gray color. [14] It has parallel wing bars on the half of the wings connected near the white patch giving it a distinctive appearance in flight. [14] The black central rectrices and typical white lateral rectrices are also noticeable in flight. [14] The iris is usually a light green-yellow or a yellow, but there have been instances of an orange color. [10] The bill is black with a brownish black appearance at the base. [10] The juvenile appearance is marked by its streaks on its back, distinguished spots and streaks on its chest, and a gray or grayish-green iris. [10]
Northern mockingbirds measure from 20.5 to 28 cm (8.1 to 11.0 in) including a tail almost as long as its body. The wingspan can range from 31–38 cm (12–15 in) and body mass is from 40–58 g (1.4–2.0 oz). Males tend to be slightly larger than females. [15] [16] Among standard measurements, the wing chord is 10 to 12 cm (3.9 to 4.7 in), the tail is 10 to 13.4 cm (3.9 to 5.3 in), the culmen is 1.6 to 1.9 cm (0.63 to 0.75 in) and the tarsus is 2.9 to 3.4 cm (1.1 to 1.3 in). [10]
The northern mockingbird's lifespan is observed to be up to 8 years, but captive birds can live up to 20 years. [17]
The mockingbird's breeding range is from the Maritime provinces westwards to British Columbia, practically the entire continental United States south of the northern Plains states and Pacific Northwest, the Greater Antilles, and the majority of Mexico to eastern Oaxaca and Veracruz. [10] The mockingbird is generally a year-round resident of its range, but the birds that live in the northern portion of its range have been noted farther south during the winter season. [14] Sightings of the mockingbird have also been recorded in Hawaii (where it was introduced in the 1920s), [18] southeastern Alaska, [19] and three times as transatlantic vagrants in Britain, [14] most recently in Exmouth, Devon, UK in February and March 2021. [20] The mockingbird is thought to be at least partly migratory in the northern portions of its range, but the migratory behavior is not well understood. [18]
In the 19th century, the range of the mockingbird expanded northward towards provinces such as Nova Scotia and Ontario and states such as Massachusetts, although the sightings were sporadic. Within the first five decades of the 20th century, regions that received an influx of mockingbirds were Maine, Vermont, Ohio, Iowa, and New York. [18] In western states such as California, the population was restricted to the Lower Sonoran Desert regions but by the 1970s the mockingbird was residential in most counties. [18] Islands that saw introductions of the mockingbird include Bermuda (in which it failed), Barbados, St. Helena, Socorro Island, the Cayman Islands and Tahiti. [18] [10]
The mockingbird's habitat varies by location, but it prefers open areas with sparse vegetation. In the eastern regions, suburban and urban areas such as parks and gardens are frequent residential areas. It has an affinity for mowed lawns with shrubs within proximity for shade and nesting. [14] [18] In western regions, desert scrub and chaparral are among its preferred habitats. When foraging for food, it prefers short grass. [14] This bird does not nest in densely forested areas, [10] [21] and generally resides in the same habitats year round. [18]
The northern mockingbird is an omnivore. [22] The birds' diet consists of arthropods (such as spiders, grasshoppers, wasps, bees, ants, beetles, butterflies, and caterpillars), earthworms, berries, fruits, seeds, and occasionally flowers, small crustaceans, and lizards ( Anolis spp.). [10] [23] [24] [25] Mockingbirds can drink from puddles, river and lake edges, or dew and rain droplets that amass onto plants. [14] Adult mockingbirds also have been seen drinking sap from the cuts on recently pruned trees. [14] Its diet heavily consists of animal prey during the breeding season, but takes a drastic shift to fruits during the fall and winter. [14] The drive for fruits amid winter has been noted for the geographic expansion of the mockingbird, and in particular, the fruit of Rosa multiflora , a favorite of the birds, is a possible link. [10] [14] Mockingbirds also eat garden fruits such as tomatoes, apples, and berries (like blackberries, raspberries, other bramble fruits, holly berries, mulberries, and dogwood), as well as grapes and figs. [26] [27] [23] [24]
These birds forage on the ground or in vegetation; they also fly down from a perch to capture food. [14] While foraging, they frequently spread their wings in a peculiar two-step motion to display the white patches. There is disagreement among ornithologists over the purpose of this behavior, with hypotheses ranging from deceleration to intimidation of predators or prey. [28] [29]
Both the male and female of the species reach sexual maturity after one year of life. The breeding season occurs in the spring and early summer. [12] The males arrive before the beginning of the season to establish their territories. They may demonstrate or contest the edges of a territory using a boundary dance in which males, typically on the ground, face each other and hop side to side, sometimes fighting, until one flies away. [30] [31] The males use a series of courtship displays to attract the females to their sites. [12] They run around the area either to showcase their territory to the females or to pursue the females. The males also engage in flight to showcase their wings. [12] They sing and call as they perform all of these displays. The species can remain monogamous for many years, but incidents of polygyny and bigamy have been reported to occur during a single bird's lifetime. [32] [33]
Both the male and female are involved in the nest building. [34] The male does most of the work, while the female perches on the shrub or tree where the nest is being built to watch for predators. The nest is built approximately three to ten feet above the ground. [34] The outer part of the nest is composed of twigs, while the inner part is lined with grasses, dead leaves, moss, or artificial fibers. The eggs are a light blue or greenish color and speckled with dots. [15] The female lays three to five eggs, and she incubates them for nearly two weeks. Once the eggs are hatched, both the male and female will feed the chicks. [34]
The birds aggressively defend their nests and surrounding areas against other birds and animals. [34] When a predator is persistent, mockingbirds from neighboring territories may be summoned by distinct calls to join the defense. Other birds may gather to watch as the mockingbirds drive away the intruder. In addition to harassing domestic cats and dogs that they consider a threat, [12] mockingbirds will at times target humans. The birds are bold, and will attack much larger birds, even hawks. One incident in Tulsa, Oklahoma involving a postal carrier resulted in the distribution of a warning letter to residents. [35]
The northern mockingbird pairs hatch about two to four broods a year. In one breeding attempt, the northern mockingbird lays an average of four eggs. [12] They are pale blue or greenish white with red or brown blotches, and measure about 25 by 18 millimetres (0.98 by 0.71 in). They hatch after about 11 to 14 days of incubation by the female. [36] After about 10 to 15 days of life, the offspring become independent. [12]
Northern mockingbirds are famous for their song repertoires. Studies have shown that males sing songs at the beginning of breeding season to attract females. [37] Unmated males sing songs in more directions and sing more bouts than mated males. In addition, unmated males perform more flight displays than mated males. [14] The mockingbirds usually nest several times during one breeding season. [38] Depending on the stage of breeding and the mating status, a male mockingbird will vary his song production. The unmated male keeps close track of this change. He sings in one direction when he perceives a chance to lure a female from the nest of the mated male. [37] Unmated males are also more likely to use elevated perches to make their songs audible farther away. [37] Though the mockingbirds are socially monogamous, mated males have been known to sing to attract additional mates. [32]
An observational study by Logan demonstrates that the female is continuously evaluating the quality of the male and his territory. [39] The assessment is usually triggered by the arrival of a new male in a neighboring territory at the beginning of a new breeding season. In those cases, the mated female is constantly seen flying over both the original and the new male's territory, evaluating the qualities of both territories and exchanging calls with both males. [39] The social mate displays aggressive behaviors towards the female, while the new male shows less aggression and sings softer songs. [39] At the same time, both the mated male and the new male will fly over other territories to attract other females as well. Separation, mate switching and extra-pair matings do occur in northern mockingbirds. [14] [39]
Northern mockingbirds adjust the sex ratio of their offspring according to the food availability and population density. Male offspring usually require more parental investment. There is therefore a bias for bearing the costlier sex at the beginning of a breeding season when the food is abundant. [40] Local resource competition predicts that the parents have to share the resources with offspring that remain at the natal site after maturation. In passerine birds, like the northern mockingbird, females are more likely to disperse than males. [41] Hence, it is adaptive to produce more dispersive sex than philopatric sex when the population density is high and the competition for local resources is intense. Since northern mockingbirds are abundant in urban environments, it is possible that the pollution and contamination in cities might affect sexual hormones and therefore play a role in offspring sex ratio. [42]
Northern mockingbirds are socially monogamous. The sexes look alike except that the male is slightly larger than the female. Mutual mate choice is exhibited in northern mockingbirds. [43] Both males and females prefer mates that are more aggressive towards intruders, and so exhibit greater parental investment. However, males are more defensive of their nests than females. In a population where male breeding adults outnumber female breeding adults, females have more freedom in choosing their mates. [43] In these cases, these female breeders have the option of changing mates within a breeding season if the first male does not provide a high level of parental care, which includes feeding and nest defense. [44] High nesting success is associated with highly aggressive males attacking intruders in the territory, and so these males are preferred by females. [44]
Northern mockingbirds are altricial, meaning that, when hatched, they are born relatively immobile and defenseless and therefore require nourishment for a certain duration from their parents. The young have a survival bottleneck at the nestling stage because there are higher levels of nestling predation than egg predation. The levels of belligerence exhibited by parents therefore increase once eggs hatch but there is no increase during the egg stage. [43]
A recent study shows that both food availability and temperature affect the parental incubation of the eggs in northern mockingbirds. Increasing food availability provides the females with more time to care for the nest and perform self-maintenance. Increasing temperature, however, reduces the time the females spend at the nest and there is increased energy cost to cool the eggs. The incubation behavior is a trade-off among various environmental factors. [45]
Mockingbird nests are also often parasitized by cowbirds.[ citation needed ] The parents are found to reject parasitic eggs at an intermediate rate. [46] A recent study has shown that foreign eggs are more likely to be rejected from a nest later in the breeding season than from earlier in a breeding season. Early nesting hosts may not have learned the pattern and coloration of their first clutch yet, so are less likely to reject foreign eggs. There is also a seasonal threshold in terms of the overlap between the breeding seasons of the northern mockingbirds and their parasites. If the breeding season of the parasites starts later, there is less likelihood of parasitism. Hence, it pays the hosts to have relatively lower sensitivity to parasitic eggs. [47]
A laboratory observation of 38 mockingbird nestlings and fledglings (thirty-five and three, respectively) recorded the behavioral development of young mockingbirds. Notable milestones, including the eyes opening, soft vocalizations, begging, and preening, began within the first six days of life. Variation in begging and more compact movements such as perching, fear crouching, and stretching appeared by the ninth day. Wing-flashing, bathing, flight, and leaving the nest happened within seventeen days (nest leaving occurred within 11 to 13 days). Improvements of flight, walking and self-feeding took place within forty days. Agonistic behavior increased during the juvenile stages, to the extent that one of two siblings living in the same area was likely killed by the other. [48]
Although many species of bird imitate the vocalizations of other birds, the northern mockingbird is the species best known in North America for doing so. Among the vocalizations it imitates are songs of the Carolina wren, northern cardinal, tufted titmouse, eastern towhee, house sparrow, wood thrush, and eastern bluebird, calls of the northern flicker and great crested flycatcher, jeers and pumphandles of the blue jay, and alarms, chups, and chirrs of the American robin. [49] [50] It imitates not only birds, but also other animals such as cats, dogs, frogs, and crickets and sounds from artificial items such as unoiled wheels and even car alarms. As convincing as these imitations may be to humans, they often fail to fool other birds, such as the Florida scrub jay. [51]
The northern mockingbird's mimicry is likely to serve as a form of sexual selection through which competition between males and female choice influence a bird's song repertoire size. [51] A 2013 study attempted to determine model selection in vocal mimics, and the data suggested that mimicry in the mockingbird resulted from the bird being genetically predisposed to learning vocalizations with acoustic characteristics such as an enlarged auditory template. [49]
Both male and female mockingbirds sing, with the latter being generally quieter and less vocal. Male commencement of singing is in late January to February and continues into the summer and the establishing of territory into the fall. Frequency in female singing is more sporadic, as it sings less often in the summer and fall, and only sings when the male is away from the territory. [14] The mockingbird also possesses a large song repertoire that ranges from 43 to 203 song types and the size varies by region. Repertoire sizes ranged from 14 to 150 types in Texas, and two studies of mockingbirds in Florida rounded estimates to 134 and 200, approximately. [14] It continually expands its repertoire during its life, [14] though it pales in comparison to mimids such as the brown thrasher. [52]
There are four recognized calls for the mockingbird: the nest relief call, hew call, chat or chatburst, and the begging call . [14] The hew call is mainly used by both sexes for potential nest predators, conspecific chasing, and various interactions between mates. One difference between chats and chatbursts is frequency of use, as chats are year-round and chatbursts occur in the fall. [14] Another difference is that chatbursts appear to be used in territorial defense in the fall and chats are used by either sex when disturbed. [14] The nest relief and begging calls are only used by the males. [14]
Adult mockingbirds can fall victim to birds of prey such as the great horned owl, screech owl and sharp-shinned hawk, though their tenacious behavior makes them less likely to be captured. Scrub jays also have killed and eaten mockingbirds. Snakes rarely capture incubating females. Fledglings have been prey to domestic cats, red-tailed hawks, and crows. Eggs and nestlings are consumed by blue jays, fish crows, American crows, red-tailed hawks, swallow-tailed kites, snakes, squirrels, and cats. Blowfly larvae and Haemoproteus have been found in Florida and Arizona populations, respectively. [18]
Winter storms limit the expansion of mockingbirds in their range. The storms have played a role in the declining of the populations in Ohio (where it has since recovered), Michigan, Minnesota and likely in Quebec. Dry seasons also affect the mockingbird populations in Arizona. [18]
In a paper published in 2009, researchers found that mockingbirds were able to recall an individual human who, earlier in the study, had approached and threatened the mockingbirds' nest. Researchers had one participant stand near a mockingbird nest and touch it, while others avoided the nest. Later, the mockingbirds recognized the intruder and exhibited defensive behavior, while ignoring the other individuals. [53] A similar paper published in 2023 had several participants exhibit varying levels of threatening behavior towards nesting mockingbirds. During a three-day training period, "high threat" participants were instructed to touch the nest daily while accompanied by a "medium threat" participant who stood three meters away. "Low threat" participants approached the nest separately and also stood three meters away for 10 minutes. When flushed from their nests by participants during a testing period, the mockingbirds retreated further from individuals who had exhibited more threatening behavior during the training period. [54]
The northern mockingbird is a species that is found in both urban and rural habitats. There are now more northern mockingbirds living in urban habitats than non-urban environments, so they are consequently known as an urban-positive species. [55] Biologists have long questioned how northern mockingbirds adapt to a novel environment in cities, and whether they fall into the typical ecological traps that are common for urban-dwelling birds. [55] A comparative study between an urban dwelling population and a rural dwelling one shows that the apparent survival is higher for individuals in the urban habitats. Lower food availability and travel costs may account for the higher mortality rate in rural habitats. [56] Urban birds are more likely to return to the nest where they had successfully bred the previous year and avoid those where breeding success was low. One explanation for this phenomenon is that urban environments are more predictable than non-urban ones, as the site fidelity among urban birds prevents them from falling into ecological traps. [56] Mockingbirds are also able to utilize artificial lighting in order to feed nestlings in urban areas such as residential neighborhoods into the night, in contrast to those that do not nest near those areas. [57] The adaptation of the mockingbird in urban habitats has led it to become more susceptible to lead poisoning in Baltimore and Washington, D.C. populations. [18]
This bird features in the title and central metaphor of the 1960 novel To Kill a Mockingbird , by Harper Lee. In that novel, mockingbirds are portrayed as innocent and generous, and two of the major characters, Atticus Finch and Miss Maudie, say it is a sin to kill a mockingbird because "they don't do one thing for us but make music for us to enjoy. They don't eat up people's gardens, don't nest in corncribs, they don't do one thing but sing their hearts out for us." [58]
The Hunger Games franchise depicts "mockingjays," mockingbirds hybridized with jabberjays, genetically engineered birds which could memorize and repeat entire human conversations. These birds appear throughout the series as a rebellious symbol. [59]
The traditional lullaby "Hush Little Baby" [60] has a line that goes "Papa's gonna buy you a mockingbird".
The song of the northern mockingbird inspired many American folk songs of the mid-19th century, such as "Listen to the Mocking Bird". [61]
Thomas Jefferson had several pet mockingbirds, including a bird named "Dick". [62] [63]
In the fictional Neighborhood of Make-Believe on Mister Rogers' Neighborhood , one of King Friday's "pets" is a wooden northern mockingbird on a stick, which he refers to by the scientific name Mimus polyglottos. [64] [65]
In 1951, Patti Page, a popular vocalist, recorded "Mockin' Bird Hill", which was sold in 10" 78 RPM format. The song reached #2 on Billboard's pop music chart and reflected gentle postwar values of the period.
The northern mockingbird is the state bird of Arkansas, [66] Florida, [67] Mississippi, [68] Tennessee, [69] and Texas, [70] and previously the state bird of South Carolina. [71]
The American white ibis is a species of bird in the ibis family, Threskiornithidae. It is found from the southern half of the US East Coast, along the Gulf Coast states and south through most of the Caribbean coastal regions of Central America. This particular ibis species is a medium-sized wading bird, possessing an overall white plumage with black wing-tips, and having the typical downward-curving bill of the ibises, though of a bright red-orange color, the same hue as its long legs. Males are larger and have longer bills than females. The breeding range runs along the Gulf and Atlantic Coast, and the coasts of Mexico and Central America. Outside the breeding period, the range extends further inland in North America and also includes the Caribbean. It is also found along the northwestern South American coastline in Colombia and Venezuela. Populations in central Venezuela overlap and interbreed with the scarlet ibis. The two have been classified by some authorities as a single species.
The tree swallow is a migratory bird of the family Hirundinidae. Found in the Americas, the tree swallow was first described in 1807 by French ornithologist Louis Vieillot as Hirundo bicolor. It has since been moved to its current genus, Tachycineta, within which its phylogenetic placement is debated. The tree swallow has glossy blue-green upperparts, with the exception of the blackish wings and tail, and white underparts. The bill is black, the eyes dark brown, and the legs and feet pale brown. The female is generally duller than the male, and the first-year female has mostly brown upperparts, with some blue feathers. Juveniles have brown upperparts, and gray-brown-washed breasts. The tree swallow breeds in the US and Canada. It winters along southern US coasts south, along the Gulf Coast, to Panama and the northwestern coast of South America, and in the West Indies.
The gray catbird, also spelled grey catbird, is a medium-sized North American and Central American perching bird of the mimid family. It is the only member of the "catbird" genus Dumetella. Like the black catbird, it is among the basal lineages of the Mimidae, probably a closer relative of the Caribbean thrasher and trembler assemblage than of the mockingbirds and Toxostoma thrashers. In some areas it is known as the slate-colored mockingbird.
The veery is a small North American thrush species, a member of a group of closely related and similar species in the genus Catharus, also including the gray-cheeked thrush, Bicknell's thrush, Swainson's thrush, and hermit thrush. Alternate names for this species include Wilson's thrush and tawny thrush. Up to six subspecies exist, which are grouped into the eastern veery, the western veery or willow thrush, and the Newfoundland veery.
The blue-headed vireo is a migrating song bird found in North and Central America. There are currently two recognized subspecies that belong to the blue-headed vireo. It has a range that extends across Canada and the eastern coast of the United-States, Mexico and some of Central America. It prefers large temperate forests with a mix of evergreen trees and deciduous under growth.
The American redstart is a New World warbler. It is unrelated to the Old World (common) redstart.
The golden-winged warbler is a New World warbler. It breeds in southeastern and south-central Canada and in the Appalachian Mountains in northeastern to north-central United States. The majority (~70%) of the global population breeds in Wisconsin, Minnesota, and Manitoba. Golden-winged warbler populations are slowly expanding northwards, but are generally declining across its range, most likely as a result of habitat loss and competition/interbreeding with the very closely related blue-winged warbler, Vermivora cyanoptera. Populations are now restricted to two regions: the Great Lakes and the Appalachian Mountains. The Appalachian population has declined 98% since the 1960s and is significantly imperiled. The U.S. Fish and Wildlife Service has been petitioned to list the species under the Endangered Species Act of 1973 and is currently reviewing all information after issuing a positive finding. Upon review, the U.S. Fish and Wildlife Service found that the petition to list the species as endangered or threatened presents "substantial scientific or commercial information indicating that listing the golden-winged warbler may be warranted."
Lincoln's sparrow is a small sparrow native to North America. It is a less common passerine bird that often stays hidden under thick ground cover, but can be distinguished by its sweet, wrenlike song. Lincoln's sparrow is one of three species in the genus Melospiza which also includes the song sparrow and the swamp sparrow. It lives in well-covered brushy habitats, often near water. This bird is poorly documented because of its secretive nature and breeding habits solely in boreal regions.
The grasshopper sparrow is a small New World sparrow. It belongs to the genus Ammodramus, which contains three species that inhabit grasslands and prairies. Grasshopper sparrows are sometimes found in crop fields and they will readily colonize reclaimed grassland. In the core of their range, grasshopper sparrows are dependent upon large areas of grassland where they avoid trees and shrubs. They seek out heterogenous patches of prairie that contain clumps of dead grass or other vegetation where they conceal their nest, and also contain barer ground where they forage for insects, spiders, and seeds. Grasshopper sparrows are unusual among New World sparrows in that they sing two distinct song types, the prevalence of which varies with the nesting cycle. The primary male song, a high trill preceded by a stereotyped series of short chips, is reminiscent of the sounds of grasshoppers and is the origin of this species' name. Like some other birds of the central North American grasslands, this species also moves around a lot, not only via annual migrations, but individuals frequently disperse between breeding attempts or breeding seasons. Grasshopper sparrows are in steep decline across their range, even in the core of the breeding distribution in the tallgrass prairies of the central Great Plains. The Florida grasshopper sparrow is highly endangered.
The sedge wren is a small and secretive passerine bird in the family Troglodytidae. It is widely distributed in North America. It is often found in wet grasslands and meadows where it nests in the tall grasses and sedges and feeds on insects. The sedge wren was formerly considered as conspecific with the non-migratory grass wren of central and South America.
The northern house wren is a very small passerine in the wren family Troglodytidae. It found in southern Canada, the USA and Mexico. It occurs in most suburban areas in its range. It formerly included many subspecies resident in South America and in the Caribbean that are now considered as separate species. The name troglodytes means "hole dweller", and is a reference to the bird's tendency to disappear into crevices when hunting insects or to seek shelter.
The black-throated blue warbler is a small passerine bird of the New World warbler family. Its breeding ranges are located in the interior of deciduous and mixed coniferous forests in eastern North America. Over the cooler months, it migrates to islands in the Caribbean and Central America. It is very rarely found in western Europe, where it is considered to be a non-indigenous species. The black-throated blue warbler is sexually dimorphic; the adult male has a black face and cheeks, deep blue upperparts and white underparts, while the adult female is olive-brown above and light yellow below.
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 Carolina wren is a common species of wren that is a resident in the Eastern United States, the extreme south of Ontario, Canada, and the extreme northeast of Mexico. Severe winters restrict the northern limits of their range, while favorable weather conditions lead to a northward extension of their breeding range. Their preferred habitat is in dense cover in forest, farm edges, and suburban areas. This wren is the state bird of South Carolina.
Helpers at the nest is a term used in behavioural ecology and evolutionary biology to describe a social structure in which juveniles and sexually mature adolescents of either one or both sexes remain in association with their parents and help them raise subsequent broods or litters, instead of dispersing and beginning to reproduce themselves. This phenomenon was first studied in birds where it occurs most frequently, but it is also known in animals from many different groups including mammals and insects. It is a simple form of co-operative breeding. The effects of helpers usually amount to a net benefit, however, benefits are not uniformly distributed by all helpers nor across all species that exhibit this behaviour. There are multiple proposed explanations for the behaviour, but its variability and broad taxonomic occurrences result in simultaneously plausible theories.
The tropical mockingbird is a resident breeding bird from southern Mexico to northern and eastern South America and in the Lesser Antilles and other Caribbean islands.
The vermilion flycatcher is a small passerine bird in the tyrant flycatcher family found throughout South America and southern North America. It is a striking exception among the generally drab Tyrannidae due to its vermilion-red coloration. The males have bright red crowns, chests, and underparts, with brownish wings and tails. Females lack the vivid red coloration and can be hard to identify—they may be confused for the Say's phoebe. The vermilion flycatcher's song is a pit pit pit pidddrrrreeedrr, which is variable and important in establishing a territory. Riparian habitats and semi-open environments are preferred. As aerial insectivores, they catch their prey while flying. Their several months-long molt begins in summer.
The chalk-browed mockingbird is a bird in the family mimidae. It is found in Brazil, Bolivia, Argentina, Paraguay, Suriname, and Uruguay.
The San Cristóbal mockingbird or Chatham mockingbird, is a species of bird in the family Mimidae. It is endemic to San Cristóbal Island in the Galápagos Islands.
The brown thrasher, sometimes erroneously called the brown thrush or fox-coloured thrush, is a bird in the family Mimidae, which also includes the New World catbirds and mockingbirds. The brown thrasher is abundant throughout the eastern and central United States and southern and central Canada, and it is the only thrasher to live primarily east of the Rockies and central Texas. It is the state bird of Georgia.
T. obscure cinereus, subtus pallide cinereus, macula alarum albida [T. dark gray, pale gray underneath, white wing spot]
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