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 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.

Seven recognized subspecies occur 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 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. Some populations have been affected by mercury contamination.

The Carolina wren was first described under the name of Sylvia ludoviciana by John Latham in 1790.^[3]^{[note 1]} Louis Jean Pierre Vieillot 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^[2]) that he created in 1816.^[7] 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.^[8]^[9]

Thryothorus used to be 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 the genus level.^[10] The Carolina wren is now the only species within this genus.^[11]

At 12.5 to 14 cm (4.9 to 5.5 in) long, with a 29 cm (11 in) wingspan and a weight of about 18 to 23 g (0.63 to 0.81 oz), 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 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).^[3] Sexual dimorphism 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.^[15]