The Carolina wren (''Thryothorus ludovicianus'') is a common

species In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of ...

wren Wrens are a family of brown passerine birds in the predominantly New World family Troglodytidae. The family includes 88 species divided into 19 genera. Only the Eurasian wren occurs in the Old World, where, in Anglophone regions, it is commonl ...

that is a resident in the eastern half of the

United States of America The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territor ...

, the extreme south of

Ontario Ontario ( ; ) is one of the thirteen provinces and territories of Canada.Ontario is located in the geographic eastern half of Canada, but it has historically and politically been considered to be part of Central Canada. Located in Central C ...

, Canada, and the extreme northeast of

Mexico Mexico ( Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guate ...

. 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 A state bird is the insignia of a nation or a state (sub-national entity). For lists of these animals, see: * List of national birds, national birds on country level * List of Australian bird emblems, for the Australian states * List of Brazilian ...

South Carolina )'' Animis opibusque parati'' ( for, , Latin, Prepared in mind and resources, links=no) , anthem = "Carolina";" South Carolina On My Mind" , Former = Province of South Carolina , seat = Columbia , LargestCity = Charleston , LargestMetro = G ...

. There are seven recognized subspecies across the range of these wrens and they differ slightly in song and appearance. The birds are generally inconspicuous, avoiding the open for extended periods of time. When out in the open, they investigate their surroundings and are rarely stationary. After finding a mate, pairs maintain a

territory A territory is an area of land, sea, or space, particularly belonging or connected to a country, person, or animal. In international politics, a territory is usually either the total area from which a state may extract power resources or a ...

and stay together for several years. Both males and females give out alarm calls, but only males sing to advertise territory. Carolina wrens raise multiple broods during the summer breeding season, but can fall victim to

brood parasitism Brood parasites are animals that rely on others to raise their young. The strategy appears among birds, insects and fish. The brood parasite manipulates a host, either of the same or of another species, to raise its young as if it were its ow ...

brown-headed cowbird The brown-headed cowbird (''Molothrus ater'') is a small, obligate brood parasitic icterid native to temperate and subtropical North America. It is a permanent resident in the southern parts of its range; northern birds migrate to the southern ...

s, among other species. Some populations have been affected by mercury contamination.

Taxonomy

The Carolina wren was first described under the name of ''Sylvia ludoviciana'' by John Latham in 1790.

Louis Jean Pierre Vieillot Louis Pierre Vieillot (10 May 1748, Yvetot – 24 August 1830, Sotteville-lès-Rouen) was a French ornithologist. Vieillot is the author of the first scientific descriptions and Linnaean names of a number of birds, including species he colle ...

considered all wrens under the genus ''Troglodytes'' and called the Carolina wren ''Troglodytes arundinaceus'' but placed it subsequently in a separate genus ''Thryothorus'' (initially misspelled ''Thriothorus'' ) that he created in 1816. ''Thryothorus'' is of

Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...

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 Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power ...

term for ''Ludovicus'' (derivative from

Louis XIV , house = Bourbon , father = Louis XIII , mother = Anne of Austria , birth_date = , birth_place = Château de Saint-Germain-en-Laye, Saint-Germain-en-Laye, France , death_date = , death_place = Palace of Ve ...

) that means 'of

Louisiana Louisiana , group=pronunciation (French: ''La Louisiane'') is a U.S. state, state in the Deep South and South Central United States, South Central regions of the United States. It is the List of U.S. states and territories by area, 20th-smal ...

' that identifies the locality of the specimen collected near

New Orleans New Orleans ( , ,New Orleans

Thryothorus used to be the largest genus in the family Troglodytidae, with 27 species, but molecular phylogenetic studies revealed that it represented a

polyphyletic A polyphyletic group is an assemblage of organisms or other evolving elements that is of mixed evolutionary origin. The term is often applied to groups that share similar features known as homoplasies, which are explained as a result of conver ...

assemblage of at least four independent clades now recognized at the genus level. The Carolina wren is now the only species within this genus. There are seven recognized subspecies of the Carolina wren: *''T. l. ludovicianus'' (Latham, 1790) – Southeast Canada (Southern Ontario, irregularly in Eastern and Southern Quebec) and the eastern United States (Southern

Wisconsin Wisconsin () is a state in the upper Midwestern United States. Wisconsin is the 25th-largest state by total area and the 20th-most populous. It is bordered by Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake M ...

and

New England New England is a region comprising six states in the Northeastern United States: Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont. It is bordered by the state of New York to the west and by the Canadian province ...

southward to

Texas Texas (, ; Spanish language, Spanish: ''Texas'', ''Tejas'') is a state in the South Central United States, South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2 ...

and northern

Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, a ...

). *''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. burleighi'' – Burleigh's Carolina wren (Lowery, 1940) Offshore islands off of the

Mississippi Mississippi () is a state in the Southeastern region of the United States, bordered to the north by Tennessee; to the east by Alabama; to the south by the Gulf of Mexico; to the southwest by Louisiana; and to the northwest by Arkansas. Mis ...

coast: Cat Island,

Ship Island (Mississippi) Ship Island is a barrier island off the Gulf Coast of Mississippi, one of the Mississippi–Alabama barrier islands. Hurricane Camille split the island into two separate islands (West Ship Island and East Ship Island) in 1969. In early 2019, t ...

, and Horn Island. *''T. l. lomitensis'' – Lomita wren (Sennett, 1890) southern Texas to the extreme northeast of Mexico (

Tamaulipas Tamaulipas (), officially the Free and Sovereign State of Tamaulipas ( es, Estado Libre y Soberano de Tamaulipas), is a state in the northeast region of Mexico; one of the 31 states which, along with Mexico City, comprise the 32 Federal Entiti ...

). *''T. l. berlandieri'' – Berlandier's wren (S. F. Baird, 1858) Northeastern Mexico (eastern

Coahuila Coahuila (), formally Coahuila de Zaragoza (), officially the Free and Sovereign State of Coahuila de Zaragoza ( es, Estado Libre y Soberano de Coahuila de Zaragoza), is one of the 32 states of Mexico. Coahuila borders the Mexican states of N ...

Nuevo León Nuevo León () is a state in the northeast region of Mexico. The state was named after the New Kingdom of León, an administrative territory from the Viceroyalty of New Spain, itself was named after the historic Spanish Kingdom of León. With ...

, and southwestern Tamaulipas) *''T. l. tropicalis'' – Northeastern Mexico (eastern San Luis Potosí 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

Yucatán Peninsula The Yucatán Peninsula (, also , ; es, Península de Yucatán ) is a large peninsula in southeastern Mexico and adjacent portions of Belize and Guatemala. The peninsula extends towards the northeast, separating the Gulf of Mexico to the north ...

of Mexico,

Belize Belize (; bzj, Bileez) is a Caribbean and Central American country on the northeastern coast of Central America. It is bordered by Mexico to the north, the Caribbean Sea to the east, and Guatemala to the west and south. It also shares a wa ...

Nicaragua Nicaragua (; ), officially the Republic of Nicaragua (), is the largest Sovereign state, country in Central America, bordered by Honduras to the north, the Caribbean Sea, Caribbean to the east, Costa Rica to the south, and the Pacific Ocean to ...

, and in Guatemala is treated as a separate species, either known as Cabot's wren or white-browed wren (''Thryothorus albinucha''). It is considered a subspecies of ''T. ludovicianus'' by some authors, however.

Description

At long, with a wingspan and a weight of about , the Carolina wren is a fairly large wren; the second largest in the United States species after the cactus wren. Among standard measurements, the wing chord is , the

tail The tail is the section at the rear end of certain kinds of animals’ bodies; in general, the term refers to a distinct, flexible appendage to the torso. It is the part of the body that corresponds roughly to the sacrum and coccyx in mammals ...

is , the culmen is and the tarsus is .

Sexual dimorphism Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most an ...

is slight with males being larger than their mates. A study indicated that of 42 mated pairs, every male but one was larger than the female of the pair. The males were on average 11 percent heavier along with having longer wing chords. There are several differences among the subspecies. For ''T. l. ludovicianus'', the

crown A crown is a traditional form of head adornment, or hat, worn by monarchs as a symbol of their power and dignity. A crown is often, by extension, a symbol of the monarch's government or items endorsed by it. The word itself is used, partic ...

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 are on the outerwebs only, but darker and more noticeable. The

rectrices Flight feathers (''Pennae volatus'') are the long, stiff, asymmetrically shaped, but symmetrically paired pennaceous feathers on the wings or tail of a bird; those on the wings are called remiges (), singular remex (), while those on the tai ...

are brown with 18 to 20 bars that span across the 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''.

Plumage

The juvenile ''T.l. ludovicianus'' is similar in appearance, but the plumage is generally paler; a softer texture, buff-tipped wing coverts, and a paler superciliary streak. In August and September, the partial plumage molt for the post-juvenile wrens is darker in color and affects the contour plumage, wing coverts, tail and develops a whiter superciliary stripe. The post-nuptial molt for adults in the same time period is more pronounced in color than the spring molt, with both sexes similar in appearance.

Life span

Survival rates differ by region. A male captured in

Arkansas Arkansas ( ) is a landlocked state in the South Central United States. It is bordered by Missouri to the north, Tennessee and Mississippi to the east, Louisiana to the south, and Texas and Oklahoma to the west. Its name is from the ...

lived to be at least 73 months old, and in

Alabama (We dare defend our rights) , anthem = " Alabama" , image_map = Alabama in United States.svg , seat = Montgomery , LargestCity = Huntsville , LargestCounty = Baldwin County , LargestMetro = Greater Birmingham , area_total_km2 = 135,7 ...

, the oldest female and male captured were six and ten years old, respectively. In a survival probability mark-and-recapture study conducted within the

Southeastern United States The Southeastern United States, also referred to as the American Southeast or simply the Southeast, is a geographical region of the United States. It is located broadly on the eastern portion of the southern United States and the southern po ...

from 1992 to 2003, roughly 90 percent of the banded wrens died within 10 years.

Similar species

The easiest species to confuse with the Carolina wren is 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 The house wren (''Troglodytes aedon'') is a very small bird of the wren family, Troglodytidae. It occurs from Canada to southernmost South America, and is thus the most widely distributed native bird in the Americas. It occurs in most suburban a ...

in being larger, with a decidedly longer

bill Bill(s) may refer to: Common meanings * Banknote, paper cash (especially in the United States) * Bill (law), a proposed law put before a legislature * Invoice, commercial document issued by a seller to a buyer * Bill, a bird or animal's beak Plac ...

and hind toe; their culmen has a notch behind the tip.

Habitat and distribution

These birds are largely resident, and will only disperse beyond their range after mild winters. Carolina wrens sporadically breed as far north as

Maine Maine () is a U.S. state, state in the New England and Northeastern United States, Northeastern regions of the United States. It borders New Hampshire to the west, the Gulf of Maine to the southeast, and the Provinces and territories of Canad ...

and

Quebec Quebec ( ; )According to the Government of Canada, Canadian government, ''Québec'' (with the acute accent) is the official name in Canadian French and ''Quebec'' (without the accent) is the province's official name in Canadian English is ...

after mild winters. In certain parts of their range, such as most of

Iowa Iowa () is a U.S. state, state in the Midwestern United States, Midwestern region of the United States, bordered by the Mississippi River to the east and the Missouri River and Big Sioux River to the west. It is bordered by six states: Wiscon ...

, prolonged periods of snow can curtail potential expansion. Permanent breeding locations range from eastern

Nebraska Nebraska () is a state in the Midwestern region of the United States. It is bordered by South Dakota to the north; Iowa to the east and Missouri to the southeast, both across the Missouri River; Kansas to the south; Colorado to the so ...

, southern

Michigan Michigan () is a U.S. state, state in the Great Lakes region, Great Lakes region of the Upper Midwest, upper Midwestern United States. With a population of nearly 10.12 million and an area of nearly , Michigan is the List of U.S. states and ...

, southeast

and the

states to Mexican states such as

, San Luis Potosí and

and the Gulf Coast of the United States. Local occurrences with infrequent and likely breeding locations include southeast

South Dakota South Dakota (; Sioux language, Sioux: , ) is a U.S. state in the West North Central states, North Central region of the United States. It is also part of the Great Plains. South Dakota is named after the Lakota people, Lakota and Dakota peo ...

, central

Kansas Kansas () is a state in the Midwestern United States. Its capital is Topeka, and its largest city is Wichita. Kansas is a landlocked state bordered by Nebraska to the north; Missouri to the east; Oklahoma to the south; and Colorado to ...

, eastern

Colorado Colorado (, other variants) is a state in the Mountain states, Mountain West subregion of the Western United States. It encompasses most of the Southern Rocky Mountains, as well as the northeastern portion of the Colorado Plateau and the wes ...

, western Oklahoma and

as far as

and

New Brunswick New Brunswick (french: Nouveau-Brunswick, , locally ) is one of the thirteen Provinces and territories of Canada, provinces and territories of Canada. It is one of the three Maritime Canada, Maritime provinces and one of the four Atlantic Canad ...

. There have been occasional vagrants spotted in

New Mexico ) , population_demonym = New Mexican ( es, Neomexicano, Neomejicano, Nuevo Mexicano) , seat = Santa Fe, New Mexico, Santa Fe , LargestCity = Albuquerque, New Mexico, Albuquerque , LargestMetro = Albuquerque metropolitan area, Tiguex , Offi ...

, and

Arizona Arizona ( ; nv, Hoozdo Hahoodzo ; ood, Alĭ ṣonak ) is a U.S. state, state in the Southwestern United States. It is the list of U.S. states and territories by area, 6th largest and the list of U.S. states and territories by population, 14 ...

Wyoming Wyoming () is a state in the Mountain West subregion of the Western United States. It is bordered by Montana to the north and northwest, South Dakota and Nebraska to the east, Idaho to the west, Utah to the southwest, and Colorado to the sou ...

Manitoba , image_map = Manitoba in Canada 2.svg , map_alt = Map showing Manitoba's location in the centre of Southern Canada , Label_map = yes , coordinates = , capital = Win ...

Nova Scotia Nova Scotia ( ; ; ) is one of the thirteen provinces and territories of Canada. It is one of the three Maritime provinces and one of the four Atlantic provinces. Nova Scotia is Latin for "New Scotland". Most of the population are native En ...

, and the Gulf of St. Lawrence. The range of the wrens increased northward and westward in several regions over the past few centuries. In

Massachusetts Massachusetts (Massachusett language, Massachusett: ''Muhsachuweesut assachusett writing systems, məhswatʃəwiːsət'' English: , ), officially the Commonwealth of Massachusetts, is the most populous U.S. state, state in the New England ...

, the wrens had expanded westward and northeastward from its former southeastern location in approximately 35 years, in

New York New York most commonly refers to: * New York City, the most populous city in the United States, located in the state of New York * New York (state), a state in the northeastern United States New York may also refer to: Film and television * '' ...

the population increased three-fold in roughly 25 years, while in the midwest states of

Ohio Ohio () is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. Of the List of states and territories of the United States, fifty U.S. states, it is the List of U.S. states and territories by area, 34th-l ...

and

, numbers have increased since the mid-1800s and early 1900s, respectively. Expansion around

occurred since early reports in 1890 and 1905. Explanations given include infrequent winter storms in the 20th century, expanded forest habitats, and the wrens taking advantage of urban areas containing feeders, especially in winter. From 1966-2015 the Carolina wren experienced a greater than 1.5% annual population increase throughout most of its northern range, extending from southern Maine to southern Nebraska. Carolina wrens adapt to various habitats. Natural habitats include various types of woodland such as

oak An oak is a tree or shrub in the genus ''Quercus'' (; Latin "oak tree") of the beech family, Fagaceae. There are approximately 500 extant species of oaks. The common name "oak" also appears in the names of species in related genera, notably ''L ...

hardwoods and mixed oak-pine woodlands,

ash Ash or ashes are the solid remnants of fires. Specifically, ''ash'' refers to all non-aqueous, non- gaseous residues that remain after something burns. In analytical chemistry, to analyse the mineral and metal content of chemical samples, ash ...

and elmwoods, hickory-oak woodlands with a healthy amount of tangled undergrowth. The preferred habitats are

riparian forest A riparian forest or riparian woodland is a forested or wooded area of land adjacent to a body of water such as a river, stream, pond, lake, marshland, estuary, canal, sink or reservoir. Etymology The term riparian comes from the Latin word ...

, brushy edges, swamps, overgrown

farmland Agricultural land is typically land ''devoted to'' agriculture, the systematic and controlled use of other forms of lifeparticularly the rearing of livestock and production of cropsto produce food for humans. It is generally synonymous with bot ...

, and

suburban A suburb (more broadly suburban area) is an area within a metropolitan area, which may include commercial and mixed-use, that is primarily a residential area. A suburb can exist either as part of a larger city/urban area or as a separa ...

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'' inhabit

slash pine ''Pinus elliottii'', commonly known as slash pine,Family, P. P. (1990). Pinus elliottii Engelm. slash pine. ''Silvics of North America: Conifers'', (654), 338. is a conifer tree native to the Southeastern United States. Slash pine is named after ...

and palmettos.

Behavior

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. Males alone sing, and have a repertoire of at least twenty different phrase patterns and on average, thirty two. One of these patterns is repeated for several minutes, and although the male's song can be repeated up to twelve times, the general number of songs range from three to five times in repetition. While singing, the tail of the birds is pointed downward. Some general vocalizations have been transcribed as ''teakettle-teakettle-teakettle'' and ''cheery-cheery-cheery''. Various descriptions of the ''teakettle'' song include ''whee-udel, whee-udel, whee-udel'', ''che-wortel, che-wortel'' and ''túrtee-túrtee-túrtee'' and familiar names and phrases such as ''sweet heart, sweet heart'', ''come to me, come to me'', ''sweet William'', and ''Richelieu, Richelieu''. Males are capable of increasing their repertoire through song learning, but due to their sedentary nature and territorial defense habits, the song learning must occur within the first three months of life. Geographic barriers affect song repertoire size from male wrens, as one study indicated that distances separated as close as by water barriers can have the same effect as that of a distance of 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 plays a role and is of behavioral relevance. Carolina Wren (7318066894)

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. Their songs can be confused with the

Kentucky warbler The Kentucky warbler (''Geothlypis formosa'') is a small species of New World warbler. It is a sluggish and heavy warbler with a short tail, preferring to spend most of its time on or near the ground, except when singing. Description Adult Ken ...

. The song patterns are similar, but the warbler's songs are described as richer, with more ringing and a hurried pace. Other bird species with songs described as akin to the wren are the flicker,

Baltimore oriole The Baltimore oriole (''Icterus galbula'') is a small icterid blackbird common in eastern North America as a migratory breeding bird. It received its name from the resemblance of the male's colors to those on the coat-of-arms of 17th century ...

, grey catbird, and more specifically the ''peto, peto, peto'' call of the tufted titmouse and the whistle of the

northern cardinal The northern cardinal (''Cardinalis cardinalis'') is a bird in the genus '' Cardinalis''; it is also known colloquially as the redbird, common cardinal, red cardinal, or just cardinal (which was its name prior to 1985). It can be found in southe ...

. Occasionally, the wrens mimic other species; in

Pennsylvania Pennsylvania (; (Pennsylvania Dutch: )), officially the Commonwealth of Pennsylvania, is a state spanning the Mid-Atlantic, Northeastern, Appalachian, and Great Lakes regions of the United States. It borders Delaware to its southeast, Ma ...

this trait has caused the bird to be also known as the 'mocking wren'.

Sexual selection

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 for potential mates 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. One aspect of territorial defense involves identifying the proximity of the threat based on the loudness of bird song as well as the level of degradation of the calls. In experiments involving playback, the wrens are capable of discriminating between degraded and undegraded songs, as well as degraded songs in the same acoustic conditions, and can detect changes of acoustic properties within their territories, such as songs under foliage. Song degradation can also be used to determine the proximity of potential intruders. If the song of a bird appears to be degraded, the wrens will assume that the threat is distant and not respond; if the song is not degraded, they respond by attacking. Not all birds within their territory are potential enemies. Some species of birds that are 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 discrepancy in responses is shown. When protecting their nest, alarm calls are the general response. The wrens judge the size of the potential threat, such as a

blue jay The blue jay (''Cyanocitta cristata'') 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 ...

and avoid the risk of injury when 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 alone produce the ''cheer'' call, which can sound indistinct. In southern regions of their 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 the songs are used 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.

Feeding

Carolina wrens spend the majority of their time on or near the ground searching for food, or in tangles of vegetation and vines. They also probe bark crevices on lower tree levels, or pick up leaf-litter in order to search for prey. Their diet consists of invertebrates, such as

beetles Beetles are insects that form the Taxonomic rank, order Coleoptera (), in the superorder Endopterygota. Their front pair of wings are hardened into wing-cases, Elytron, elytra, distinguishing them from most other insects. The Coleoptera, wit ...

true bugs Hemiptera (; ) is an order of insects, commonly called true bugs, comprising over 80,000 species within groups such as the cicadas, aphids, planthoppers, leafhoppers, assassin bugs, bed bugs, and shield bugs. They range in size from to a ...

, grasshoppers,

katydid Insects in the family Tettigoniidae are commonly called katydids (especially in North America), or bush crickets. They have previously been known as "long-horned grasshoppers". More than 8,000 species are known. Part of the suborder Ensifera, ...

spider Spiders (order Araneae) are air-breathing arthropods that have eight legs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude silk. They are the largest order of arachnids and rank seventh in total species d ...

ant Ants are eusocial insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from vespoid wasp ancestors in the Cretaceous period. More than 13,800 of an estimated total of 22,0 ...

bee Bees are winged insects closely related to wasps and ants, known for their roles in pollination and, in the case of the best-known bee species, the western honey bee, for producing honey. Bees are a monophyletic lineage within the superfamil ...

s, and

wasp A wasp is any insect of the narrow-waisted suborder Apocrita of the order Hymenoptera which is neither a bee nor an ant; this excludes the broad-waisted sawflies (Symphyta), which look somewhat like wasps, but are in a separate suborder. Th ...

s. Small

lizard Lizards are a widespread group of squamate reptiles, with over 7,000 species, ranging across all continents except Antarctica, as well as most oceanic island chains. The group is paraphyletic since it excludes the snakes and Amphisbaenia al ...

s and

tree frog A tree frog (or treefrog) is any species of frog that spends a major portion of its lifespan in trees, known as an arboreal state. Several lineages of frogs among the Neobatrachia have given rise to treefrogs, although they are not closely rela ...

s also make up the carnivorous portion of their diet. Vegetable matter, such as fruit pulp and various

seed A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiosper ...

s, makes up a small percentage of their diet. In the northern portion of their range, they frequent

bird feeder A birdfeeder, bird table, or tray feeder are devices placed outdoors to supply bird food to birds ( bird feeding). The success of a bird feeder in attracting birds depends upon its placement and the kinds of foods offered, as different species ...

Movement

Carolina wrens are wary, and are more often heard than seen. When on the ground, they move in jerky hops pillaging through various objects, whether man-made or natural. While moving abruptly, they pause momentarily for chattering or singing. When stationary, they move in twitched motions, jerking their breast around. They also sun- or sand-bathe. The wrens also displays a skittish behavior when encountered by

human Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, culture, ...

s, as they can be seen thrusting off into cover slowly if approaching is detected. However, they occasionally seek out humans that are near, so long as there is no movement from them. Other movements involve being capable of crawling like a creeper and hanging upside-down like a

nuthatch The nuthatches () constitute a genus, ''Sitta'', of small passerine birds belonging to the family Sittidae. Characterised by large heads, short tails, and powerful bills and feet, nuthatches advertise their territory using loud, simple songs. Mo ...

. Flights are generally of short duration, rapid, low-leveled, and wavelike. The wings during flight are flapped rapidly, and are frequently used during foraging. They are also capable of flying vertically from the base of a tree to the top in a single wing assisted bound.

Breeding

Carolina Wren nesting in a duck box - Flickr - Andrea Westmoreland

Carolina wrens are both genetically and socially

monogamous Monogamy ( ) is a form of dyadic relationship in which an individual has only one partner during their lifetime. Alternately, only one partner at any one time ( serial monogamy) — as compared to the various forms of non-monogamy (e.g., polyg ...

and will usually mate for life. Mate changing is rare, and there has been one possible observation of polygamy. During the winter season, males are more responsible for guarding the territory. Females vary in succeeding to maintain winter territories without a mate. It has been suggested that the possibility of desertion and decline in care-taking from males along with the need for security in resources year-round prevent extra pair copulations from females, as the mortality rate for Carolina wrens peaks during the winter. Along with thermoregulatory benefits,

roosting Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...

is thought to reinforce pair-bonding and prevent divorce between mates. The nests are arch-shaped structures with a side entrance and built of dried plants or strips of bark, as well as horsehair, string, wool and snake sloughs. The male obtains nesting materials while the female remains at the site to construct the nest. Nests are located in fragmented or complete cavities in trees, or in man-made structures such as bird-boxes, buildings, tin cans, mailboxes or unorthodox places such as pockets of hanging jackets in sheds or in a

tractor A tractor is an engineering vehicle specifically designed to deliver a high tractive effort (or torque) at slow speeds, for the purposes of hauling a trailer or machinery such as that used in agriculture, mining or construction. Most comm ...

in everyday use. Nests are from from the ground and are rarely higher. They occasionally can be built in sloping locations or at 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 3 to 6 eggs, but can reach as high as seven in Texas. The eggs are creamy white with brown or reddish-brown spots, and are more heavily marked at the broad end. The eggs are incubated by the female for 12–16 days. After the young hatch, they are fed exclusively on invertebrates and they fledge in 12–14 days. As many as three broods may be raised by a pair in a single breeding season. In one study, three of the 70 fledglings remained or defended territory adjacent to 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.

Predation and threats

Brood parasitism Brood parasites are animals that rely on others to raise their young. The strategy appears among birds, insects and fish. The brood parasite manipulates a host, either of the same or of another species, to raise its young as if it were its ow ...

by the

is common, with up to 25% of Carolina wren nests being affected in certain regions such as Oklahoma and

. Cowbird parasitism peaks in April at 41%, and is as low as 8% and 0% in July and August, respectively. Female cowbirds sometimes eject Carolina wren eggs before laying their own, and even if host eggs are retained, the size of cowbird eggs negatively affect the hatching success of wren eggs. As a result, cowbirds may have a significant impact on the reproductive success of wrens. The feeding rate for cowbird nestlings is higher than wren feeding rates, and some have been raised to independence. This also can be detrimental to the survival of wren nestlings. A rare instance of brood-parasitism by a

house finch The house finch (''Haemorhous mexicanus'') is a bird in the finch family Fringillidae. It is native to western North America and has been introduced to the eastern half of the continent and Hawaii. This species and the other two American ros ...

has been recorded. The rate of brood parasitism is thought to be lower in more natural and concealed nesting locations. Body parasites such as the larvae of blowflies feed on nestlings and the blood loss weakens nestlings. Fellow species of wren such as Bewick's wren and the winter wren compete for nesting locations and food, respectively. In

Virginia Virginia, officially the Commonwealth of Virginia, is a state in the Mid-Atlantic and Southeastern regions of the United States, between the East Coast of the United States, Atlantic Coast and the Appalachian Mountains. The geography an ...

, some Carolina wrens populations show high levels of mercury in their blood and this is acquired from feeding all-year-round on spiders. Spiders being at a higher

trophic level The trophic level of an organism is the position it occupies in a food web. A food chain is a succession of organisms that eat other organisms and may, in turn, be eaten themselves. The trophic level of an organism is the number of steps it i ...

contain a higher concentrations of mercury (through

biomagnification Biomagnification, also known as bioamplification or biological magnification, is any concentration of a toxin, such as pesticides, in the tissues of tolerant organisms at successively higher levels in a food chain. This increase can occur as a ...

) than herbivorous invertebrates. As these wrens are year-round residents, they are at a higher risk than other species to acquire mercury in their blood. Nest abandonment and failure to raise young are more common with higher mercury content. Exposure, and prolonged periods of cold, ice, and snow is thought to affect the wren nestling and adult populations, respectively. Wrens that outlast those winters reside in sheltered areas during the season. Among the top predators of adult Carolina wrens are domestic cats, and snakes such as the

timber rattlesnake The timber rattlesnake, canebrake rattlesnake, or banded rattlesnake (''Crotalus horridus'') Wright AH, Wright AA (1957). ''Handbook of Snakes of the United States and Canada''. Ithaca and London: Comstock Publishing Associates, a division of ...

Raccoon The raccoon ( or , ''Procyon lotor''), sometimes called the common raccoon to distinguish it from other species, is a mammal native to North America. It is the largest of the procyonid family, having a body length of , and a body weight o ...

s and black rat snakes also feed on wren eggs and nestlings.

In culture

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 The northern mockingbird (''Mimus polyglottos'') is a mockingbird commonly found in North America. This bird is mainly a permanent resident, but northern birds may move south during harsh weather. This species has rarely been observed in Europe ...

as the state bird. In 1948, the legislature repealed their previous decision, and the wren became the official state bird. In 2000, the Carolina wren was featured on the back of the South Carolina edition of the 50 State Quarters.

Notes

References

External links

Identification tips
– USGS Patuxent Bird Identification InfoCenter
About
– Bird Houses 101

– BirdLife International * *
Sound
– Florida Museum of Natural History {{Taxonbar, from=Q1585636

Carolina wren The Carolina wren (''Thryothorus ludovicianus'') is a common species of wren that is a resident in the eastern half of the United States of America, the extreme south of Ontario, Canada, and the extreme northeast of Mexico. Severe winters restri ...

Native birds of Eastern Canada Native birds of the Eastern United States Birds of Mexico Birds of the Yucatán Peninsula