Biology:ʻŌmaʻo

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Short description: Species of bird

ʻŌmaʻo
Oma'o (9-4-2017) Pu'u O'o trail, Kipuka Ainahou section, Hawai'i co, Hawaii -04jpg (37545163396).jpg
Scientific classification edit
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Passeriformes
Family: Turdidae
Genus: Myadestes
Species:
M. obscurus
Binomial name
Myadestes obscurus
(J.F. Gmelin, 1789)

The ʻōmaʻo (Myadestes obscurus), also called the Hawaiian thrush, is an endemic species of robin-like bird found only on the island of Hawaii. ʻŌmaʻo are closely related to the other endemic thrushes of the Hawaiian Islands, the kāmaʻo, the olomaʻo, and the puaiohi. ʻŌmaʻo are found primarily in rainforests in the eastern and southeastern regions of the Big Island. Population estimates approximate 170,000 birds, making it the most common of the Hawaiian thrushes. It appears to have a stable population, but because the entire population exists on a small range and is endemic to a single island, it is considered vulnerable.[1]

Taxonomy

The ʻōmaʻo was formally described in 1789 by the German naturalist Johann Friedrich Gmelin in his revised and expanded edition of Carl Linnaeus's Systema Naturae. He placed it with the flycatchers in the genus Muscicapa and coined the binomial name Muscicapa obscura.[2] The specific epithet is from Latin and means "dark" or "dusky".[3] Gmelin based his account on the "Dusky fly-catcher" that had been described in 1783 by the English ornithologist John Latham in his book A General Synopsis of Birds. Latham had examined a specimen from the "Sandwich Islands", now the Hawaiian Islands, that belonged to the Leverian Museum in London.[4] The ʻōmaʻo in now placed in the genus Myadestes that was introduced in 1838 by the English ornithologist William John Swainson. The species is monotypic: no subspecies are recognised.[5]

Description

Illustration by Joseph Smit

Adult thrushes (males and females are similar in appearance) are mostly nondescript, with a grayish-brown head transitioning to a pale gray below. The back and primaries are a dull olive brown. They also have whitish vents and undertail coverts. The juveniles are also similarly dull in coloration, but have pale whitish-buff spotting on the wing coverts.[6]

Behaviour

‘Ōma’os are mostly frugivores, but will take insects or other small invertebrates.[7] The bird has a song that is a set of jerky liquid notes, whip-per-weeo-whip-per-weet.[8] Their many calls include a catlike rasp, a frog like croak and even a high pitched police whistle type sound.[6] During breeding, the birds make a bulky nest in a tree or tree fern, laying one to three bluish eggs inside.[9]

Habitat

The ‘ōma’o once lived on most of the land of Hawaii. Today it is restricted to the southern and eastern slopes of the island, mostly above 1,000 meters above sea level, 25 to 30 percent of its ancestral habitat. Its preferred habitat is rainforest, but can be found in high shrublands on Mauna Loa.[10] Preferred trees include the ohia and koa. The Hawaiian thrush avoids areas with banana poka (an invasive vine). In lower elevations, it appears to be gaining a natural resistance to avian malaria.[6] Threats to this species include habitat destruction from housing and farming; introduced feral animal predation (mainly rats, cats and mongoose); invasive plant encroachment; and feral livestock such as pigs.[1]

The species has been aided by several conservation actions. These include the removal of pigs from several areas in the 1990s, such as Hakalau Forest National Wildlife Refuge.[11]

References

  1. 1.0 1.1 1.2 BirdLife International (2016). "Myadestes obscurus". IUCN Red List of Threatened Species 2016: e.T22708579A94165878. doi:10.2305/IUCN.UK.2016-3.RLTS.T22708579A94165878.en. https://www.iucnredlist.org/species/22708579/94165878. Retrieved 13 November 2021. 
  2. Gmelin, Johann Friedrich (1789) (in Latin). Systema naturae per regna tria naturae : secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. 1, Part 2 (13th ed.). Lipsiae [Leipzig]: Georg. Emanuel. Beer. p. 945. https://www.biodiversitylibrary.org/page/2656440. 
  3. Jobling, James A. (2010). The Helm Dictionary of Scientific Bird Names. London: Christopher Helm. p. 278. ISBN 978-1-4081-2501-4. https://archive.org/stream/Helm_Dictionary_of_Scientific_Bird_Names_by_James_A._Jobling#page/n278/mode/1up. 
  4. Latham, John (1783). A General Synopsis of Birds. 2, Part 1. London: Printed for Leigh and Sotheby. p. 344, No. 42. http://biodiversitylibrary.org/page/33730507. 
  5. Gill, Frank; Donsker, David; Rasmussen, Pamela, eds (July 2023). "Thrushes". IOC World Bird List Version 13.2. International Ornithologists' Union. http://www.worldbirdnames.org/bow/thrushes/. 
  6. 6.0 6.1 6.2 Wakelee, Katherine M.; Fancy, Steven G. (4 March 2020). "Omao (Myadestes obscurus)". Birds of the World. doi:10.2173/bow.omao.01. https://birdsoftheworld-org.elibrary.calgarypubliclibrary.com/bow/species/omao/cur/identification. Retrieved 1 February 2024. 
  7. "‘Ōma‘o" (in en). Hawaii Government. 23 August 2021. https://dlnr.hawaii.gov/wildlife/birds/omao/. 
  8. "Species factsheet: Myadestes obscurus". 2024. http://datazone.birdlife.org/species/factsheet/omao-myadestes-obscurus/text. 
  9. Berger, Andrew (1981). Hawaiian Birdlife. Univerisy of Hawaii Press. doi:10.1515/9780824885649. 
  10. Van Ripper III, Charles; Scott, J. Michael (February 1979). "Observations on Distribution, Diet, and Breeding of the Hawaiian Thrush". The Condor 81 (1): 65. doi:10.2307/1367858. https://www.jstor.org/stable/1367858. Retrieved 1 February 2024. 
  11. "Hakalau Forest National Wildlife Refuge". official web site of United States Fish and Wildlife Service. http://www.fws.gov/hakalauforest/. 

External links

Wikidata ☰ Q3179495 entry