|Recorded in Cape May, New Jersey, US|
|Genus:||Thryothorus (but see text)
|Range of T. ludovicianus Year-round range|
The Carolina wren (Thryothorus ludovicianus) is a common species of wren, resident in the eastern half of the USA, the extreme south of Ontario, Canada, and the extreme northeast of Mexico. Severe winters can limit its population in northern regions of its range, but will navigate northward for breeding if weather conditions are favorable. The preferred living quarters are either dense coverage or abandoned buildings. This wren is the state bird of South Carolina.
There are seven subspecies for the Carolina wren. There are numerous differences in songs, appearance, and living quarters for the subspecies. The bird is generally inconspicuous, and will make an effort to avoid being in the open for extended periods of time. When out in the open, it will investigative its surroundings. The male also takes responsibility in performing songs in order to protect its territory.
The bird is monogamous and once it finds it mate and territory, it will usually reside in that territory for life. These wrens have multiple broods in a breeding season, but can fall victim to parasitism to cowbirds. It also has populations that have been affected with mercury poisoning.
The Carolina wren was first described as Motacilla troglodytes by Johann Friedrich Gmelin in 1788. It was later renamed Sylvia Ludovicianus by John Latham in 1790. The Thryothorus portion of its scientific name was coined by Louis Jean Pierre Vieillot in 1816. Its generic name thryothorus is of Greek origin from the combination of thryon (rush, reed) and thouros (derivative of verb throskein to leap up, spring, jump at) which means 'Reed Jumper'; its specific name ludovicianus is a post-classical Latin term for Ludovicus (derivative from Louis XIV) that means 'of Louisiana' that identifies the locality of the specimen collected near New Orleans.
T.l. ludovicianus (Latham, 1790) - Southeast Canada (Southern Ontario, irregularly in Eastern and Southern Quebec) and the eastern United States (Southern Wisconsin and New England southward to Texas and northern Florida).
T.l. miamensis Florida Wren (Ridgway, 1875) - Florida from approximately 30 degrees (Gainesville) region southward through the rest of the state.
T.l. nesophilus (Stevenson, 1973) - Dog Island in Northwestern Florida.
T.l. lomitensis - Lomita's Wren (Sennett, 1890) southern Texas to the extreme northeast of Mexico (Tamaulipas).
T.l. tropicalis - Northeastern Mexico (eastern San Luis Potosi and southern Tamaulipas).
T. ludovicianus is traditionally placed within its own genus as its only representative of North America, but recent DNA work suggests it is closely allied with the Bewick's wren. A distinct population in the Yucatan Peninsula of Mexico, Belize, Nicaragua, and in Guatemala is treated as a separate species, either known as Cabot's wren or white-browed wren (Thryothorus albinucha). It is sometimes considered a subspecies of T. ludovicianus for some authors, however.
Typically 12.5 to 14 cm (4.9 to 5.5 in) with a 29 cm (11 in) wingspan and a weight of about 18 to 23 g (0.63 to 0.81 oz), it is a fairly large wren; among the United States species it is second largest after the cactus wren. Among standard measurements, the wing chord is 5.4 to 6.4 cm (2.1 to 2.5 in), the tail is 4.5 to 5.6 cm (1.8 to 2.2 in), the culmen is 1.4 to 1.8 cm (0.55 to 0.71 in) and the tarsus is 2 to 2.3 cm (0.79 to 0.91 in). Male sexual dimorphism is prevalent in this species.
There are noted differences among the subspecies. For T.l. ludovicianus, the crown is rich brown that appears more chestnut-colored on its rump and uppertail-coverts. Shoulders and greater coverts are a rich brown, with a series of small white dots on the lesser primary coverts. The secondary coverts are rich brown with a darker brown barring on both webs; the bars on the primaries is on the outerwebs only, but darker and more noticeable. The retrices are brown with 18 to 20 bars that span across its tail. The white supercilious streak borders thinly with a black above and below, and extends above and beyond its shoulders. The ear coverts are speckled gray and grayish-black. Its chin and throat are grey that becomes buff on its chest, flank and belly, though the latter two are of a warmer color. The underwing coverts sport a grayish buff color. Its iris is reddish-brown, the upper mandible is lemon-colored and paler at the base and lower mandible. The legs are flesh-colored.
As for the other subspecies in contrast to T.l. ludovicianus, T.l. berlandieri is of a slightly smaller build, but possesses a larger bill, the upperparts are duller brown with deeper colored underparts, T.l. lomitensis is of a duller color (than either ludovicianus or berlandieri with its underparts either pale or almost white, T.l. miamensis contains darker rusty chestnut upperparts and deeper colored below. T.l. burleighi is duller and sootier with less distinct tail markings, T.l. mesophilus has paler underparts and a whiter supercilium, and T.l. tropicalis is darker than all races, and contains heavier bars than T.l. berlandieri.
The juvenile T.l. ludovicianus is similar in appearance, but generally paler, with buff-tipped wing coverts and a fluffy vent and crissum without bars.
Survival rates vary by region. A male captured in Arkansas lived to be at least 73 months old, and in Alabama, the oldest and female and male captured were six and ten years old, respectively. A mark-and-recapture analysis of the wrens analyzing survival probability within the Southeastern United States captured were monitored from 1992 to 2003. Of the 2878 captured, 293 returned.
The easiest species to confuse with the Carolina wren is the Bewick's wren, which differs in being smaller but with a longer tail, grayer-brown above and whiter below. The Carolina and white-browed wrens differ from the house wren in being larger, with a decidedly longer bill and hind toe; their culmen has a notch behind the tip.
Habitat and Distribution
This bird is largely a nonmigratory species, and will only resort to extending beyond its range after mild winters. In certain regions, the wren will breed sporadically in places as north as Maine and Quebec after mild winters. In certain zones of range, such as most of Iowa, prolonged periods of snow can curtail its potential expansion. There has been occasional vagrants spotted in Colorado, New Mexico, and Arizona, Wyoming, South Dakota, Manitoba, New Brunswick, Nova Scotia, and the Gulf of St. Lawrence.
Cactus wrens can adapt to various habitats. Natural habitats will involve many types of woodland include oak hardwoods and mixed oak-pine woodlands, ash and elmwoods, hickory-oak woodlands with a healthy amount of tangled undergrowth. Its preferred habitats are riparian forests, brushy edges, swamps, overgrown farmlands, and suburban yards with abundant thick shrubs and trees, and parks. It has an affinity for dilapidated buildings and unkempt yards in man-made areas. Subspecies burleighi and neophilus will inhabit slash pine and palmettos.
Song and Calls
Carolina wrens sing year round and at any point during the daytime, with the exception of performing during the most harsh weather conditions. The birds are also the only species in the Certhiidae family that neither sing in duet nor has its song control regions affect its repertoire size. The males are the ones capable of singing, and utilize a repertoire of at least twenty different phrase patterns, though the average repertoire amount for the males is 32. One of these patterns is generally repeated for several minutes, and the male's song can be repeated up to twelve times, though the general amount of songs range from three to five times in repetition. While singing, the tail of the birds is pointed downward. Notable vocalizations include the teakettle-teakettle-teakettle and cheery-cheery-cheery.
Males are also capable of song learning to increase its repertoire, but due to its sedentary nature and territorial defense habits, the song learning must occur within the first three months of life. Geographic barriers can affect song repertoire size from male wrens, as one study indicated that distances separated as close as 3 kilometres (1.9 mi) by water barriers can have the same effect as that of a distance of 145 kilometres (90 mi) in the mainland with no barriers.
Female Carolina wrens possess song control regions that would appear to make them capable of singing with repertoires like the male. Due to vocalizations that they occasionally make with the male, it has been suggested that song perception play a role and is of behavioral relevance.
Different subspecies have variations in songs and calls, such as miamensis having a more rapid song that contains more notes than the races that are further north.
This bird's song can be confused with the Kentucky warbler. The song patterns are similar, but the quality is different, as the warbler's song is described as richer, with more ringing and a hurried pace. Occasionally, the wren mimics other species, and in Pennsylvania it has led for it to be also known as the 'Mocking wren'.
A 2006 study suggested that the correlation of tail length and body size in males, wing length in females, and lifespan for both sexes were signs of individual quality, and the wrens of high quality tend to mate with like individuals. The courting and antagonistic encounters that involve the tail fanning and wing drooping was suggested to be a possible signaling use. Age and life experience are not thought of as significant due to their relatively short lifespan and sedentary lifestyle. Due to the large size of male wrens and the male's vigor in defending its territory, intrasexual selection was given as a possible explanation for the sexual dimorphism.
Territorial and Predator Defense
Both sexes are involved in defending the territory. The wrens are capable of discriminating between the degraded and undegraded songs, as well as degraded songs in the same acoustic conditions, and detect changes of acoustic properties within their territories, such as songs under foliage. Song degradation can also be utilized to determine the proximity of potential intruders. If the song of a bird appears to be degrading, the wren will not respond as if in any amount of danger; if the song is not degrading, it will respond with attacking. Not all birds within its territory are potential enemies. Some species of birds that are territorial neighbors are designated as 'dear-enemies' by the wrens, and the responses to neighbors and intruders in their territories differ by the season. In spring, the wrens respond more aggressively toward neighbors, though in the fall, no major discrepancies in responses are shown. When protecting its nest, alarm calls are the general response. The wrens may determine the size of the potential threat, such as a blue jay in order to prevent injury while attacking. Countersinging produced by intruder birds is more likely to be taken as an aggressive threat to male Carolina wrens.
Both males and females utilize calls in alarm situations, especially in territorial disputes and encounters with predators. Males are the only sex capable of performing the cheer call, which can sound burred and slurry. In southern regions of its range, the sound males use in alarm disputes is a ringing pink or p'dink sound. Females are the only ones that can perform the paired dit-dit or chatter sounds. The former can be used in territorial disputes with predators, and with at least northern populations can sing in alternation with the males cheer chant. The chatter is used exclusively with territorial encounters with male song, and the song can either follow or overlap her mate's song.
Cactus wrens generally spend the majority of its time on or near the ground searching for food, or in tangles of vegetation and vines. They also probe bark crevices on lower levels of trees, or pick up leaf-litter in order to search for prey. Their diet mainly consists of invertebrates, such as beetles, true bugs, grasshoppers, katydids, spiders, ants, bees, and wasps. Small lizards and tree frogs also make up the carnivorous portion of its diet. Vegetable matter makes up a small percentage of their diets, such as fruit pulp and various seeds. In the northern portion of its range, it frequents bird feeders.
Cactus wrens are wary, and are more often heard than seen. When on the ground, it will move in jerky hops pillaging through various objects, whether man-made or natural. When stationary, it generally moves in twitched motions, jerking its breast around. It may also be seen sun-bathing or sand-bathing. The various movements involve being capable of crawling like a creeper and hanging upside-down like a nuthatch.
Flights are generally of short duration, rapid, low-leveled, and wavelike. The wings during flight are flapped rapidly, and are frequently used during foraging. It is also capable of flying vertically from the base of a tree to the top in a single wing assisted bound.
Carolina wrens are both generically and socially monogamous and will usually mate for life, and mate changing is rare; however, there has been one possible instance of polygamy. During the winter season, males are more responsible for guarding the territory. Females may or may not be able to maintain winter territory without a mate. It has been suggested that the threat of male desertion and reduced care from the males along with the need for mutual resource defenses year-round prevent extra pair copulations, as the mortality rate for Carolina wrens are at its highest during the winter. Along with thermoregulatory benefits, roosting is thought to reinforce pair-bonding and prevent divorce between mates.
The nest is generally a dome-shaped structure with a side entrance that can be built with various materials that range from dried vegetation, grass, strips of bark, to non-plant material such as horsehair, string, wool and snake skin. Males are generally responsible for the retrieving of materials while the female remains at the site to construct. Nests are typically located in partial or complete cavities in natural places like trees, or human constructs such as bird-boxes, buildings, tin cans, mailboxes or even in places as odd as pockets of hanging jackets in sheds. Nests are generally from 1–3 m (3.3–9.8 ft) from the ground and are rarely higher. They occasionally can be build in sloping locations or even ground level.
Egg laying dates and clutch size vary by region; in Texas the time period is from late February to late August, in Iowa it ranges from late April to June. The clutch size is generally size is 3 to 6 eggs, but can reach as high as seven in Texas. The appearance of the eggs is white and creamy with white spots that are either brown or reddish-brown, and is more heavily marked at the blunt end. The incubation period is handled by the female and it lasts for 12–16 days. After the young hatch, they are fed exclusively on invertebrates and the fledgling period in 12–14 days. As many as three broods per breeding season occur with this species. In one study, three of the 70 fledglings remained or defended territory adjacent from the natal area.
Male and females are involved in the process of provisioning at similar rates throughout most nest stages, with the males providing slightly more in the nestling stages. Both sexes increase their provision rates as the nestlings grow in age. Males showing quality to their spouse is thought to play a major role, however, mate change in the species is rare.
Predation and threats
Cowbird parasitism from brown-headed cowbirds is likely frequent with this species, with up to 25% of its nests being affected in certain regions. The height of cowbird parasitism during the nesting period is in April at 41%, and as low as 8% and 0% in July and August, respectively. As a result, cowbirds may have significant impact on reproductive success of the wrens. The feeding rate for cowbird nestlings is higher than wren feeding rates, and some have been raised to independence. House finches have also victimized the wrens by parasitism. The rate of brood parasitism is thought to be lower in more natural and concealed nesting locations, however. Body parasites such as blowflies have fed on nestlings, and the blood loss may weaken nestlings.
In certain habitats where mercury contamination is in the water sources, Carolina wrens are more likely to have higher concentrations of it in its body due to its heavy reliance on spiders and its non-migratory habits. Nest abandonment and lack of reproductive success were more commonplace with the higher mercury content. Exposure, and prolonged periods of cold, ice, and snow is thought to have affect the wren nestling and adult populations, respectively.
In 1930, the South Carolina Federated Women's club adopted the Carolina wren as the unofficial state bird over the eastern mourning dove and pushed for its official state adoption until 1939, when the South Carolina Legislature named the northern mockingbird as the state bird. In 1948, the legislature repealed their previous decision, and the wren became the official state bird.
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|Wikimedia Commons has media related to the Carolina wren.|
|Wikispecies has information related to: Thryothorus ludovicianus|
- Identification tips - USGS Patuxent Bird Identification InfoCenter
- Species account – Cornell Lab of Ornithology
- About - Bird Houses 101
- Stamps - BirdLife International
- Carolina wren videos, photos, and sounds at the Internet Bird Collection
- Carolina wren photo gallery at VIREO (Drexel University)
- Sound - Florida Museum of Natural History
Category:Troglodytidae Category:Thryothorus Category:Bird genera Wren, Carolina Wren, Carolina Wren, Carolina Wren, Carolina Wren, Carolina Wren, Carolina Wren, Carolina Category:Monotypic bird genera Category:Animals described in 1790