Eastern bluebird Temporal range: | |
---|---|
Pair in Michigan | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Aves |
Order: | Passeriformes |
Family: | Turdidae |
Genus: | Sialia |
Species: | S. sialis |
Binomial name | |
Sialia sialis | |
Geographic distribution of S. sialis Breeding range Year-round range Wintering range | |
Synonyms | |
Motacilla sialisLinnaeus, 1758 |
The eastern bluebird (Sialia sialis) is a small North American migratory thrush found in open woodlands, farmlands, and orchards.
The bright-blue breeding plumage of the male, easily observed on a wire or open perch, makes this species a favorite of birders. The male's call includes sometimes soft warbles of jeew or chir-wi, or the melodious song chiti WEEW wewidoo. [2] It is the state bird of Missouri [3] and New York. [4]
The eastern bluebird was formally described by the Swedish naturalist Carl Linnaeus in 1758 in the tenth edition of his Systema Naturae under the binomial name Motacilla sialis. [5] The type location is South Carolina. [6] Linnaeus based his short Latin description on the earlier more detailed descriptions by the English naturalists Mark Catesby and George Edwards. [7] [8] The eastern bluebird is now placed in the genus Sialia that was introduced by the English naturalist William John Swainson in 1827 with the eastern bluebird as the type species. [9] [10]
Seven subspecies are recognised: [10]
Eastern bluebirds measure 16–21 cm (6.3–8.3 in) long, span 25–32 cm (9.8–12.6 in) across the wings, and weigh 27–34 g (0.95–1.20 oz). [12] [11]
Male bluebirds have a bright head, back, and wings. Their breast is a brownish red. [12] Females are lighter with gray on the head and back and some blue on their wings and tail. In females, the breast is usually lighter in color than in males, and is more orange. [12]
The eastern bluebird is found east of the Rockies, southern Canada to the Gulf states, and southeastern Arizona to Nicaragua. The increase in trees throughout the Great Plains during the past century due to fire suppression and tree planting facilitated the western range expansion of the species. [13] as well as range expansions of many other species of birds. [14] [15] [16] From 1966–2015 the eastern bluebird experienced a greater than 1.5% annual population increase throughout most of its breeding and year-round ranges, with exceptions including southern Florida and the Ohio River valley. [17]
Bluebirds tend to live in open country around trees, but with little understory and sparse ground cover. Original habitats probably included open, frequently burned pine savannas, beaver ponds, mature but open woods, and forest openings. Today, they are most common along pastures, agricultural fields, suburban parks, backyards, and even golf courses. Populations also occur across eastern North America and south as far as Nicaragua. Birds that live farther north and in the west of the range tend to lay more eggs than eastern and southern birds. [18]
An isolated, insular subspecies of the eastern bluebird is found on Bermuda, and has a distinctive, brighter blue coloration compared to mainland populations. This population was formerly thought to have been predated the colonization of the islands (making it one of only three extant, resident pre-colonization Bermuda landbirds, alongside the Bermuda white-eyed vireo and gray catbird). However, analysis of fossil strata found no evidence for the existence of bluebirds on the islands prior to European colonization. Using simulations and molecular evidence, a 2013 study found that the Bermuda bluebirds likely descend from very small founder population from a single colonization event during the 1600s. This colonization event could either be a natural one by migratory individuals or an anthropogenic introduction by early settlers, who are known to have introduced several other eastern North American birds like the northern cardinal (Cardinalis cardinalis) to Bermuda very shortly after colonization. It is likely that the alteration to the islands' ecosystem due to the clearing of native forest facilitated this colonization by providing optimal bluebird feeding habitat, along with a lack of predators. [19] [20]
Eastern bluebirds are social, and will sometimes gather in flocks of over a hundred. However, they are territorial during the breeding season and may continue to defend a feeding area throughout the winter.
Mating occurs in the spring and summer. A mature female typically raises two broods each season. Nests are constructed in trees within abandoned woodpecker holes or other cavities that provide adequate protection (usually several feet above ground). Construction of the nest is done primarily by the female and takes around 10 days to complete. These nests are small, cup-like structures lined with grass, feathers, stems, and hairs. Each female lays three to seven light-blue or, rarely, white eggs. The female incubates the eggs, which hatch after 13 to 16 days. The young cannot care for themselves upon hatching. The female broods the chicks for up to seven days after hatching. Fledglings then leave the nest 15 to 20 days after hatching. [11]
Both parents cooperate in raising the young, which they feed a diet consisting almost entirely of insects. Some young stay around the nest to help raise another brood. Fledglings are grayish in color, with speckled breasts. The blue color becomes much more prominent and the speckles on their breasts disappear as they mature. Bluebirds may begin breeding the summer after they are hatched. [11]
Eastern bluebirds can live for 6 to 10 years. The longest recorded lifespan for a bluebird is 10 years and five months. [18] However, most bluebirds die within their first year of life. Starvation and freezing are a danger to the young, but most threats come from other animals, including humans. Natural predators of eggs and nestlings can include eastern chipmunks, flying squirrels, American black bears, fire ants, and raccoons. Bluebirds of all ages (including adults) are threatened by rat snakes, racers, American kestrels, and domestic cats. Introduced species such as European starlings and house sparrows are competitors for nesting sites. Non-nesting adults face predation by all native species of falcons, owls, and most varieties of hawks, particularly those in the genus Accipiter . When approached by a predator, the male makes a song-like warning cry. If no male is present, a threatened female will begin to sing, hoping to attract a protective male back to the territory. Both males and females also flick their wings and warble when predators are nearby. [11]
About two thirds of an adult bluebird's diet consists of insects and other invertebrates. The remainder is made up of wild fruits or berries. It has a preference for grasshoppers, crickets, katydids, and beetles; and will also eat earthworms, spiders, millipedes, centipedes, sowbugs, and snails.
Bluebirds feed by perching on a high point, such as a branch or fence post, and swooping down to catch insects on or near the ground. The availability of a winter food source will often determine whether or not a bird will migrate. If bluebirds do remain in a region for the winter, they group and seek cover in heavy thickets, orchards, or other areas in which adequate food and cover resources are available.
Eastern bluebirds thrived in the 1700s and 1800s. This flourishing is thought to be connected with the activity of settlers. Clearing forests made new habitat available for bluebirds and nesting sites were created in the increasing numbers of apple orchards and in wooden fence posts that eventually rotted. [21] It is believed that bluebirds were most abundant around 1900. However, increasing competition with the invasive species of European starlings (Sturnus vulgaris) and house sparrows (Passer domesticus) along with loss of farmland began to take a toll on bluebird populations. [21] Along with these, pesticides and scarcity of food during winter compounded to cause the number of bluebirds to fall. [22] A definite drop has been shown to have occurred between 1938 and the late 1970s. [21]
Conservation efforts are seen as early as 1934 when Thomas Musselman created the first bluebird trail by setting up rows of bluebird houses along roads. [21] Also in the 1930s, William Duncan created a bluebird house design and educated others about these birds. [21] In 1964, The National Association for Protection and Propagation of the Purple Martin and Bluebirds of America was founded. After it went out of existence, the Nature Society kept up with conservation work. [21] Lawrence Zeleny's 1976 book, The Bluebird: How You Can Help Its Fight For Survival, and a National Geographic article he wrote helped make the plight of these birds well known. [21] In 1978, the North American Bluebird Society was founded. [21]
If the Bermuda population of bluebirds is considered the product of natural colonization, it has also become highly endangered. Early settlers described individual flocks numbering over 50 birds each flying across the islands, but in the present only 500 individuals are thought to remain. The near-extinction of Bermuda cedar (Juniperus bermudiana) forest in the 1940s and 1950s wiped out the majority of natural nesting habitat for bluebirds, leaving it almost completely dependent on artificial nest boxes for breeding. Introduced starlings and house sparrows evict bluebirds from their nests, and introduced great kiskadees (Pitangus sulphuratus) feed on juvenile birds. They are also threatened by feral cats and pesticides. [20]
Bluebirds were popular with early American colonists and associated with the coming of spring. They were referred to as the 'blue robin' because of their resemblance to the European robin. [22] Bluebirds have been mentioned in the works of many writers including Thoreau's writings, Robert Frost's "The Last Word of a Bluebird (as told to a child)", the "Over the Rainbow" song from The Wizard of Oz , the song "Zip-A-Dee-Doo-Dah" ("Mister Bluebird's on my shoulder") from Disney's Song of the South , [23] and John Burrough's "The Bluebird". [21] Lawrence Zeleny said that bluebirds represent joy to Americans. [22]
The eastern bluebird is featured prominently on the current obverse of the Bermudian $2 bill. [24]
The blue jay is a passerine bird in the family Corvidae, native to eastern North America. It lives in most of the eastern and central United States; some eastern populations may be migratory. Resident populations are also in Newfoundland, Canada; breeding populations are found across southern Canada. It breeds in both deciduous and coniferous forests, and is common in residential areas. Its coloration is predominantly blue, with a white chest and underparts, and a blue crest; it has a black, U-shaped collar around its neck and a black border behind the crest. Males and females are similar in size and plumage, and plumage does not vary throughout the year. Four subspecies have been recognized.
The bluebirds are a North American group of medium-sized, mostly insectivorous or omnivorous birds in the order of Passerines in the genus Sialia of the thrush family (Turdidae). Bluebirds are one of the few thrush genera in the Americas.
The wood duck or Carolina duck is a partially migratory species of perching duck found in North America. The male is one of the most colorful North American waterfowls.
The hooded merganser is a species of fish-eating duck in the subfamily Anatinae. It is the only extant species in the genus Lophodytes. The genus name derives from the Greek language: lophos meaning 'crest', and dutes meaning 'diver'. The bird is striking in appearance; both sexes have crests that they can raise or lower, and the breeding plumage of the male is handsomely patterned and coloured. The hooded merganser has a sawbill but is not classified as a typical merganser.
The common eider, also called St. Cuthbert's duck or Cuddy's duck, is a large sea-duck that is distributed over the northern coasts of Europe, North America and eastern Siberia. It breeds in Arctic and some northern temperate regions, but winters somewhat farther south in temperate zones, when it can form large flocks on coastal waters. It can fly at speeds up to 113 km/h (70 mph).
The common goldeneye or simply goldeneye is a medium-sized sea duck of the genus Bucephala, the goldeneyes. Its closest relative is the similar Barrow's goldeneye. The genus name is derived from the Ancient Greek boukephalos, a reference to the bulbous head shape of the bufflehead. The species name is derived from the Latin clangere.
The bufflehead is a small sea duck of the genus Bucephala, the goldeneyes. It breeds in Alaska and Canada and migrates in winter to southern North America. This species was first described by Carl Linnaeus in his landmark 1758 10th edition of Systema Naturae as Anas albeola.
The northern hawk-owl or northern hawk owl is a medium-sized true owl of the northern latitudes. It is non-migratory and usually stays within its breeding range, though it sometimes irrupts southward. It is one of the few owls that is neither nocturnal nor crepuscular, being active only during the day. This is the only living species in the genus Surnia of the family Strigidae, the "typical" owls. The species is sometimes called simply the hawk owl; however, many species of owls in the genus Ninox are also called "hawk owls".
The western bluebird is a small North American thrush.
The mountain bluebird is a migratory small thrush that is found in mountainous districts of western North America. It has a light underbelly and black eyes. Adult males have thin bills and are bright turquoise-blue and somewhat lighter underneath. Adult females have duller blue wings and tail, grey breast, grey crown, throat and back. In fresh fall plumage, the female's throat and breast are tinged with red-orange which is brownish near the flank, contrasting with white tail underparts. Their call is a thin 'few' while their song is a warbled high 'chur chur'. The mountain bluebird is the state bird of Idaho and Nevada. This bird is an omnivore and it can live 6 to 10 years in the wild. It eats spiders, grasshoppers, flies and other insects, and small fruits. The mountain bluebird is a relative of the eastern and western bluebirds.
The red-bellied woodpecker is a medium-sized woodpecker of the family Picidae. It breeds mainly in the eastern United States, ranging as far south as Florida and as far north as Canada. Though it has a vivid orange-red crown and nape it is not to be confused with the red-headed woodpecker, a separate species of woodpecker in the same genus with an entirely red head and neck that sports a solid black back and white belly. The red-bellied earns its name from the pale reddish tint on its lower underside.
The eastern meadowlark is a medium-sized blackbird, very similar in appearance to sister species western meadowlark. It occurs from eastern North America to northern South America, where it is also most widespread in the east. The Chihuahuan meadowlark was formerly considered to be conspecific with the eastern meadowlark.
The eastern phoebe is a small passerine bird. The genus name Sayornis is constructed from the specific part of Charles Lucien Bonaparte's name for Say's phoebe, Muscicapa saya, and Ancient Greek ornis, "bird". Phoebe is an alternative name for the Roman moon-goddess Diana, but it may also have been chosen to imitate the bird's call.
The eastern kingbird is a large tyrant flycatcher native to the Americas. The bird is predominantly dark gray with white underbelly and pointed wings. Eastern kingbirds are conspicuous and are commonly found in open areas with scattered trees and bushes, where they perch while foraging for insects. The Eastern kingbird is migratory, with its breeding range spread across North America and its wintering range in Central and South America.
The western kingbird is a large tyrant flycatcher found throughout western environments of North America, as far south as Mexico.
The violet-green swallow is a small North American passerine bird in the swallow family. These aerial insectivores are distributed along the west coast from Alaska to Mexico, extending as far east as Montana and Texas. With an appearance very similar to the tree swallow, these individuals can be identified by the white rump side-patches that appear to separate their green back and purple tail. Violet-green swallows are secondary cavity nesters, found in a number of habitats including deciduous and coniferous forest. In addition to nesting in tree holes within these habitats, they are also widely observed nesting in the cracks of large cliffs.
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The purple martin is a passerine bird in the swallow family Hirundinidae. It is the largest swallow in North America. Despite its name, the purple martin is not truly purple. The dark blackish-blue feathers have an iridescent sheen caused by the diffraction of incident light giving them a bright blue to navy blue or deep purple appearance. In some light, they may even appear green in color.
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.
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