Wrenthrush

The wrenthrush or zeledonia (Zeledonia coronata) is a unique species of nine-primaried oscine bird which is endemic to Costa Rica and Panama.

Wrenthrush
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Class: Aves
Order: Passeriformes
Superfamily: Emberizoidea
Family: Zeledoniidae
Ridgway, 1907
Genus: Zeledonia
Ridgway, 1889
Species:
Z. coronata
Binomial name
Zeledonia coronata
Ridgway, 1889

Taxonomy and systematics

The wrenthrush is the only member of its genus and family. Despite its name, it is neither a wren (Troglodytidae) nor a thrush (Turdidae), and is not closely related to either of those families. Over time it has been treated as related to thrushes and Old World flycatchers (Muscicapidae) and by the late 20th century was placed as a member of the New World warblers (Parulidae). Phylogenetic studies of nuclear and mitochondrial DNA after that date led to reassessment of several genera and in 2017 the wrenthrush was moved to its own family. The exact placement of that family is still not firmly settled, but most taxonomic systems agree that it is closely related to the spindalises (Spindalidae), Cuban warblers (Teretistridae), and several other small Caribbean families, and more distantly related to New World sparrows (Passerellidae) and New World blackbirds (Icteridae).[2][3][4] BirdLife International's Handbook of the Birds of the World places it much closer to the New World sparrows and blackbirds than do the others.[5]

The wrenthrush's genus name commemorates José Castulo Zeledón, a Costa Rican ornithologist.[6] It is monotypic.[3]

Wrenthrush in the Central Highlands of Costa Rica

Description

The wrenthrush is 10 to 11.5 cm (3.9 to 4.5 in) long and weighs about 21 g (0.74 oz). It is short-tailed and rather plump, with a short thin bill somewhat like that of a Parulidae warbler. The sexes are alike. Adults have a large yellow-orange patch with black borders on their crown. Their face and the sides of their neck are leaden gray. Their upperparts, tail, and flanks are dull olive bronze. Their underparts are leaden gray with an olive tinge to the undertail coverts. Juveniles do not have the orange crown and their upperparts are more brownish than those of adults.[6]

Distribution and habitat

The wrenthrush is found from the Cordillera de Guanacaste in northern Costa Rica discontinuously through that country into western Panama's Chiriquí and Veraguas provinces. It inhabits montane evergreen forest and elfin forest, landscapes characterized by constant wetness and fog. It particularly favors dense vegetation near streams, including stands of Chusquea bamboo. In elevation it ranges from about 1,500 m (4,900 ft) up to treeline; in Costa Rica it mostly occurs around 2,500 m (8,200 ft).[6]

Behavior

Movement

The wrenthrush is essentially sedentary, with minimal elevational movement.[6]

Locomotion

The wrenthrush is a weak flier, seldom taking to the wing and then for only short distances. It has short rounded wings and a small keel to which flight muscles attach, and there was early speculation that it is evolving towards flightlessness.[6][7]

Feeding

The wrenthrush forages by hopping among branches and along the ground searching for arthropods, especially spiders and Lepidoptera larvae. It mostly forages in dense vegetation, though it occasionally works the edges of it and also hunts as high as 10 m (30 ft) above the ground in vines and epiphytes.[6]

Breeding

The wrenthrush's breeding season appears to span from March to early July. Few nests have been found. They were domes made of moss, twigs, and leaves with a side entrance and a lining of dried leaves, grass, and moss. They were placed in cavities in earthen banks and were partially hidden by overhanging vegetation. The clutch size in three nests was three eggs. The incubation period is not known; the time from hatch to fledging appears to be at least 18 days. Both parents provision the nestlings.[6]

Vocalization

Both sexes of wrenthrush sing, and often as a duet. They are more vocal during the breeding season, and mostly sing at dawn and dusk though they can be heard throughout the day. Their primary song is described as "ssee-del-deet with emphasis on the ending, deet", and it may be sung in a series for several minutes. Their primary call is "a thin pseee".[6]

Status

The IUCN has assessed the wrenthrush as being of Least Concern. It has a small range and its population size is unknown but believed to be stable. No immeditate threats have been identified.[1] "[H]abitat degradation and destruction could become a concern" but "its specialized high-altitude habitat seems not to be presently under threat".[6]

References

  1. BirdLife International (2016). "Zeledonia coronata". IUCN Red List of Threatened Species. 2016: e.T22722054A94746073. doi:10.2305/IUCN.UK.2016-3.RLTS.T22722054A94746073.en. Retrieved 11 October 2022.
  2. Chesser, R. T., S. M. Billerman, K. J. Burns, C. Cicero, J. L. Dunn, B. E. Hernández-Baños, R. A. Jiménez, A. W. Kratter, N. A. Mason, P. C. Rasmussen, J. V. Remsen, Jr., D. F. Stotz, and K. Winker. 2022. Check-list of North American Birds (online). American Ornithological Society. https://checklist.aou.org/taxa
  3. Gill, F.; Donsker, D.; Rasmussen, P., eds. (August 2022). "Caribbean "tanagers", Wrenthrush, Yellow-breasted Chat". IOC World Bird List. v 12.2. Retrieved 9 August 2022.
  4. Clements, J. F., T. S. Schulenberg, M. J. Iliff, S. M. Billerman, T. A. Fredericks, J. A. Gerbracht, D. Lepage, B. L. Sullivan, and C. L. Wood. 2021. The eBird/Clements checklist of Birds of the World: v2021. Downloaded from https://www.birds.cornell.edu/clementschecklist/download/ Retrieved August 25, 2021
  5. HBW and BirdLife International (2021) Handbook of the Birds of the World and BirdLife International digital checklist of the birds of the world. Version 6. Available at: http://datazone.birdlife.org/userfiles/file/Species/Taxonomy/HBW-BirdLife_Checklist_v6_Dec21.zip retrieved August 7, 2022
  6. Dupont, G., J. Curson, and A. J. Spencer (2020). Wrenthrush (Zeledonia coronata), version 2.0. In Birds of the World (T. S. Schulenberg, S. M. Billerman, and B. K. Keeney, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.wrenth1.02 retrieved October 11, 2022
  7. Pycraft, W. P. (1905) On the systematic position of Zeledonia coronata, with some observations on the position of the Turdidae. Ibis series 8, volume 5: 1-24

Further reading

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