The wrens are mostly small, brownish passerine birds in the mainly New World family Troglodytidae. There are approximately 80 species of true wrens in approximately 20 genera. Only the Eurasian Wren occurs in the Old World, where in Anglophone regions it is commonly known simply as the "wren" as it is the originator of the name. The name wren has been applied to other unrelated birds, particularly the New Zealand wrens (Acanthisittidae) and the Australian wrens (Maluridae).
Most wrens are small and rather inconspicuous, except for their loud and often complex songs. Notable exceptions are the relatively large members of the genus Campylorhynchus, which can be quite bold in their behavior. Wrens have short wings that are barred in most species, and they often hold their tails upright. As far as known, wrens are primarily insectivorous, eating insects, spiders and other small arthropods, but many species also eat vegetable matter and some will take small frogs/lizards.
Name and use of the term wren
The English name wren derives from Middle English wrenne, Old English wraenna, attested (as werna) very early, in an 8th century gloss. It is cognate to Old High German wrendo, wrendilo and Icelandic rindill (the latter two including an additional diminutive -ilan suffix). The Icelandic name is attested in Old Icelandic (Eddaic) rindilþvari. This points to a Common Germanic name *wrandjan-, but the further etymology of the name is unknown.
The wren is also known as kuningilin "kinglet" in Old High German, a name associated with the fable of the election of the "king of birds". The bird who could fly to the highest altitude would be made king. The eagle outflew all other birds, but he was beaten by a small bird who had hidden in his plumage. This fable is already known to Aristotle (Hist. animalium 9.11) and Plinius (Naturalis hist. 10.74 ), and was taken up by medieval authors such as Johann Geiler von Kaisersberg, but it concerns Regulus, and is apparently motivated by the yellow "crown" sported by these birds (a point noted already by Ludwig Uhland). In modern German the name is "Zaunkönig", king of the fence (or hedge). In Dutch the name is "winterkoninkje" (little winter king).
The family name Troglodytidae is derived from troglodyte, which means "cave-dweller", and the wrens get their scientific name from the tendency of some species to forage in dark crevices.
The name "wren" is also ascribed to other families of passerine birds throughout the world. In Europe, species of Regulus are commonly known as "wrens", the Common Firecrest and Goldcrest as "fire-crested wren" and "golden-crested wren", respectively.
The 27 Australasian "wren" species in the family Maluridae are unrelated, as are the New Zealand wrens in the family Acanthisittidae, the antwrens in the family Thamnophilidae, and the wren-babblers of the family Timaliidae.
Wrens are medium-small to very small birds. The Eurasian Wren is among the smallest birds in its range, while the smaller species from the Americas are among the smallest passerines in that part of the world. They range in size from the White-bellied Wren, which averages under 10 centimetres (3.9 in) and 9 grams (0.32 oz), to the Giant Wren, which averages about 22 centimetres (8.7 in) and weighs almost 50 grams (1.8 oz). The dominating colours of their plumage are generally drab, composed of grey, brown, black and white, and most species show some barring, especially to tail and/or wings. There is no sexual dimorphism in the plumage of wrens, and little difference between young birds and adults. All have fairly long, straight to marginally decurved bills.
Wrens have loud and often complex songs, sometimes given in duet by a pair. The song of members of the genera Cyphorhinus and Microcerculus have been considered especially pleasant to the human ear, leading to common names such as Song Wren, Musician Wren, Flutist Wren and Southern Nightingale-Wren.
Distribution and habitat
Wrens are principally a New World Family, distributed from Alaska and Canada to southern Argentina, with the greatest species richness in the Neotropics. As suggested by its name, the Eurasian Wren is the only species of wren found outside the Americas, as restricted to Europe, Asia and northern Africa (it was formerly considered conspecific with the Winter Wren and Pacific Wren of North America). There are a number of insular species, including the Clarion Wren and Socorro Wren from the Revillagigedo Islands in the Pacific Ocean, and the Cobb's Wren in the Falkland Islands, but few Caribbean islands have a species of wren, with only the Southern House Wren in the Lesser Antilles, the Cozumel Wren of Cozumel Island, and the highly restricted Zapata Wren in a single swamp in Cuba.
The various species occur in a wide range of habitats, ranging from dry, sparsely wooded country to rainforest. Most species are mainly found at low levels, but members of the genus Campylorhynchus are frequently found higher, and the two members of Odontorchilus are restricted to the forest canopy. A few species, notably the Eurasian Wren and the House Wren, are often associated with humans. Most species are resident, remaining in Central and South America all year round, but the few species found in temperate regions of the Northern Hemisphere are partially migratory, spending the winter further south.
Behaviour and ecology
Wrens vary from highly secretive species such as those found in the genus Microcerculus to the highly conspicuous genus Campylorhynchus, the members of which will frequently sing from exposed perches. The family as a whole exhibits a great deal of variation in their behaviour. Temperate species generally occur in pairs, but some tropical species may occur in parties of up to twenty birds.
Though little is known about the feeding habits of many of the Neotropical species, wrens are considered primarily insectivorous, eating insects, spiders and other small arthropods. Many species also take vegetable matter such as seeds and berries, some (primarily the larger species) will take small frogs/lizards, the Eurasian Wren has been recorded wading into shallow water to catch small fish and tadpoles, the Sumichrast's Wren and Zapata Wren will take snails, and the Giant Wren and Marsh Wren have been recorded attacking and eating bird eggs (in the latter species, even eggs of conspecifics). A local Spanish name for the Giant Wren and Bicolored Wren is chupahuevo ("egg-sucker"), but whether the latter actually eats eggs is unclear. The Plain Wren and Northern House Wren sometimes destroy bird eggs, and the Rufous-and-white Wren has been recorded killing nestlings, but this is apparently to eliminate potential food competitors rather than feed on the eggs/nestlings. Several species of Neotropical wrens sometimes participate in mixed-species flocks or follow army ants, and the Eurasian Wren may follow Badgers to catch prey items disturbed by them.
Taxonomy and systematics
Revised following Martínez Gómez et al. (2005) and Mann et al. (2006). The taxonomy of some groups is highly complex, and future species-level splits are likely. Additionally, undescribed taxa are known to exist. The Black-capped Donacobius is an enigmatic species traditionally placed with the wrens more for lack of a more apparent alternative and/or thorough study. It was more recently determined to be most likely closer to certain "warblers", possibly the newly established Megaluridae, and might constitute a monotypic family.
- Genus Odontorchilus
- Genus Microcerculus
- Genus Hylorchilus
- Genus Campylorhynchus
- Band-backed Wren (Campylorhynchus zonatus)
- Bicolored Wren (Campylorhynchus griseus)
- Boucard's Wren (Campylorhynchus jocosus)
- Cactus Wren (Campylorhynchus brunneicapillus)
- Fasciated Wren (Campylorhynchus fasciatus)
- Giant Wren (Campylorhynchus chiapensis)
- Gray-barred Wren (Campylorhynchus megalopterus)
- Rufous-naped Wren (Campylorhynchus rufinucha)
- Spotted Wren (Campylorhynchus gularis)
- Stripe-backed Wren (Campylorhynchus nuchalis)
- Thrush-like Wren (Campylorhynchus turdinus)
- White-headed Wren (Campylorhynchus albobrunneus)
- Yucatan Wren (Campylorhynchus yucatanicus)
- Genus Thryothorus
- Genus Cinnycerthia
- Genus Cantorchilus (formerly included in Thryothorus)
- Stripe-breasted Wren (Cantorchilus thoracicus)
- Stripe-throated Wren (Cantorchilus leucopogon)
- Plain Wren (Cantorchilus modestus)
- Canebrake Wren (Cantorchilus (modestus) zeledoni)
- Riverside Wren (Cantorchilus semibadius)
- Bay Wren (Cantorchilus nigricapillus)
- Superciliated Wren (Cantorchilus superciliaris)
- Buff-breasted Wren (Cantorchilus leucotis) (probably not monophyletic)
- Fawn-breasted Wren (Cantorchilus guarayanus)
- Long-billed Wren (Cantorchilus longirostris)
- Gray Wren (Cantorchilus griseus)
- Genus Thryophilus (formerly included in Thryothorus)
- Genus Pheugopedius (formerly included in Thryothorus)
- Moustached Wren (Pheugopedius genibarbis)
- Coraya Wren (Pheugopedius coraya)
- Whiskered Wren (Pheugopedius mystacalis)
- Plain-tailed Wren (Pheugopedius euophrys)
- Black-bellied Wren (Pheugopedius fasciatoventris)
- Black-throated Wren (Pheugopedius atrogularis)
- Sooty-headed Wren (Pheugopedius spadix)
- Speckle-breasted Wren (Pheugopedius sclateri)
- Happy Wren (Pheugopedius felix)
- Inca Wren (Pheugopedius eisenmanni)
- Rufous-breasted Wren (Pheugopedius rutilus)
- Spot-breasted Wren (Pheugopedius maculipectus)
- Genus Cyphorhinus
- Genus Henicorhina - wood-wrens
- Genus Troglodytes (10-15 species, depending on taxonomy; includes Nannus which may be distinct however)
- Genus Cistothorus
- Kroodsma, Donald; Brewer, David (2005), "Family Troglodytidae (Wrens)", in del Hoyo, Josep; Elliott, Andrew; Christie, David, Handbook of the Birds of the World. Volume 10, Cuckoo-shrikes to Thrushes, Barcelona: Lynx Edicions, pp. 356–447, ISBN 84-87334-72-5
- Kluge-Lutz, English Etymology tentatively suggest association with Old High German (w)renno "stallion", but Suolahti (1909) rejects this as unlikely.
- Suolahti, Viktor Hugo, Die deutschen Vogelnamen : eine wortgeschichtliche Untersuchung, Straßburg (1909), 80-85.
- Perrins, C. (1991). Forshaw, Joseph. ed. Encyclopaedia of Animals: Birds. London: Merehurst Press. pp. 190. ISBN 1-85391-186-0.
- Alström, Per; Ericson, Per G.P.; Olsson, Urban; Sundberg, Per (2006). "Phylogeny and classification of the avian superfamily Sylvioidea". Molecular Phylogenetics and Evolution 38 (2): 381–97. doi:10.1016/j.ympev.2005.05.015. PMID 16054402.
- Mann, Nigel I.; Barker, F. Keith; Graves, Jeff A.; Dingess-Mann, Kimberly A. & Slater, Peter J. B. (2006): Molecular data delineate four genera of "Thryothorus" wrens. Molecular Phylogenetics and Evolution 40: 750–759. doi:10.1016/j.ympev.2006.04.014 (HTML abstract)