Carolina wren - WikiHQ

thumb|Thryothorus ludovicianus

The Carolina wren (Thryothorus ludovicianus) is a species of wren common in the eastern United States, the extreme south of Ontario, Canada, the northeast and southeast of Mexico, and into northern Central America. 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.

Ten subspecies are recognized, occurring across the range of the species; they differ slightly in song and appearance. It is generally inconspicuous, avoiding the open for extended periods of time. When out in the open, they energetically investigate their surroundings and are rarely stationary. After finding a mate, pairs maintain a territory 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 by brown-headed cowbirds, among other species.

Taxonomy

The Carolina wren was first described under the name of Sylvia ludoviciana by John Latham in 1790. Louis Pierre Vieillot at first considered all wrens under the genus Troglodytes and called the Carolina wren Troglodytes arundinaceus, but subsequently placed it in a separate genus Thryothorus (initially misspelled Thriothorus)

Etymology

The genus name Thryothorus is of Greek origin from the combination of the noun θρύον : thrýon ("rush, reed") and the adjective θοῦρος : thoũros ("rushing, impetuous"; derivative of verb θρῴσκειν : thrōskein to leap up, spring, jump at). Thus, Thryothorus means 'reed jumper'.

Its specific name ludovicianus is a post-classical Latin term for Ludovicus (derivative from Louis XIV) meaning 'of Louisiana' that identifies the locality of the specimen collected near New Orleans.

Species

Thryothorus used to be considered the largest genus in the family Troglodytidae, with 27 species, but molecular phylogenetic studies revealed that it represented a polyphyletic assemblage of at least four independent clades now recognized at generic level, with the other 26 species split off in the genera Cantorchilus, Pheugopedius, and Thryophilus. The Carolina wren is now the only species within this genus; DNA work suggests it is most closely allied to Bewick's wren Thryomanes bewickii.

Relationships of the Carolina wren to selected other wrens:

Description

alt=Carolina Wren|left|thumb|335x335px|Carolina wren in [[Greenville, South Carolina ]]

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 is , the culmen is and the tarsus is .

For T. l. ludovicianus, the crown is rich brown that appears more chestnut-colored on its rump and upper tail 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 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 dark gray to pinkish-gray, paler at the base and on the lower mandible. The legs are light pinkish to yellowish-brown color. In certain parts of their range, such as most of Iowa, prolonged periods of snow can curtail potential expansion. Permanent breeding locations range from eastern Nebraska, southern Michigan, southeast Ontario and the New England states to Mexican states such as Coahuila, Nuevo León, San Luis Potosí and Tamaulipas and the Gulf Coast of the United States.

Carolina wrens adapt to various habitats. Natural habitats include various types of woodland such as oak hardwoods and mixed oak-pine woodlands, ash and elmwoods, hickory-oak woodlands with a healthy amount of tangled undergrowth. 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 ranges 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.

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. 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 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, true bugs, grasshoppers, katydids, spiders, ants, bees, and wasps. Small lizards and tree frogs also make up the carnivorous portion of their diet. Vegetable matter, such as fruit pulp and various seeds, makes up a small percentage of their diet. In the northern portion of their range, they frequent bird feeders. When stationary, they move in twitched motions, jerking their breast around. The wrens also displays a skittish behavior when encountered by humans, 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.

Breeding

thumb|Carolina wren nesting in a duck nestbox

Carolina wrens are both genetically and socially monogamous and will usually mate for life. Mate changing is rare, Along with thermoregulatory benefits, roosting 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 in everyday use.

Predation and threats

Although Carolina wrens are fairly common, brood parasitism by the brown-headed cowbird is common, with up to 25% of Carolina wren nests being affected in certain regions such as Oklahoma and Alabama. The rate of brood parasitism is thought to be lower in more natural and concealed nesting locations. Fellow species of wren such as Bewick's wren and the winter wren compete for nesting locations and food, respectively. Exposure, and prolonged periods of cold, ice, and snow is thought to affect the wren nestling and adult populations, respectively. Raccoons and black rat snakes also feed on wren eggs and nestlings.

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