Ryukyu robin (Erithacus komadori)

Kingdom	Animalia
Phylum	Chordata
Class	Aves
Order	Passeriformes
Family	Muscicapidae
Genus	Erithacus (1)

The Ryukyu robin is classified as Near Threatened (NT) on the IUCN Red List (1).

The Ryukyu robin (Erithacus komadori) is a small passerine that is found only on the Nansei Shoto archipelago (2). This species has been designated as a ‘natural monument’ in Japan, and is therefore of high academic interest (3).

The male has a black breast, white underparts and dull orange upperparts. The female Ryukyu robin is smaller than the male, and both the female and juvenile lack the characteristic black breast of the male (4).

The Ryukyu robin is endemic to the Nansei Shoto archipelago in Japan (2).

Three subspecies are currently recognised, each occurring on different islands or parts of the islands. Erithacus komadorisubrufa occurs on the islands of Iriomote, Ishigaki and Yonaguni, Erithacus komadorinamiyei is found only in the northern part of Okinawa Island, and Erithacus komadorikomadori inhabits the southern islands of Kagoshima and Okinawa (2)

The Ryukyu robin inhabits dense undergrowth in damp areas of evergreen forest, at elevations of up to 600 metres (2).

Little is known about the biology of the Ryukyu robin. However, species in the genus Erithacus typically feed on invertebrates, soft fruits and seeds (5).

The Ryukyu robin will nest in crevices or among tree roots (2). Well known for being very territorial, the Ryukyu robin will fiercely defend its nest (5).

This species is a partial migrant, with many of the birds relocating to more southerly parts of the Nansei Shoto archipelago during the colder months (2).

The Ryukyu robin population is relatively small and in slow decline. Commercial logging activities mean that habitat loss and degradation are major threats for this species (2).

Steep declines in the population size of this species have been reported on some islands. Introduced mongooses on Okinawa, and weasels on Nakanoshima, prey on the native Ryukyu robin, further reducing its numbers (2).

The Ryukyu robins is designated a natural monument in Japan, meaning any activities that may have an effect on its condition or conservation first need approval from the Commissioner for Cultural Affairs in Japan (3).

No active conservation measures are known to specifically target the Ryukyu robin, but this species does make use of artificial nest boxes erected within its habitat. Monitoring of this species population, range size and suitable habitat is needed before proper conservation measures can be proposed. Possible actions to protect the Ryukyu robin include predator control and a reduction in commercial logging (2).

To find out more about the Ryukyu robin and its conservation:

• Birdlife International - Ryukyu robin
  http://www.birdlife.org/datazone/speciesfactsheet.php?id=6590

To find out more about the Nansei Shoto archipelago:

• WWF - Nansei Shoto Archipelago Forests Factsheet
  http://wwf.panda.org/about_our_earth/ecoregions/nanseishoto_archipelago_forests.cfm

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
arkive@wildscreen.org.uk

• Endemic: a species or taxonomic group that is only found in one particular country or geographic area.
• Evergreen forest: forest consisting mainly of evergreen trees, which retain leaves all year round. This is in contrast to deciduous trees, which completely lose their leaves for part of the year.
• Invertebrates: animals with no backbone, such as insects, crustaceans, worms, molluscs, spiders, cnidarians (jellyfish, corals, sea anemones) and echinoderms.
• Passerines: a group of more than 5,000 species of small to medium-sized birds, sometimes known as perching birds or song birds, which have widely varied plumage and shape. They all have three toes pointing forward and one pointed backward, which assists with perching.
• Subspecies: a population usually restricted to a geographical area that differs from other populations of the same species, but not to the extent of being classified as a separate species.
• Territorial: describes an animal, a pair of animals or a group that occupies and defends an area.

1. IUCN Red List (November, 2011)
   http://www.iucnredlist.org/
2. Birdlife International (November, 2011)
   http://www.birdlife.org/datazone/speciesfactsheet.php?id=6590
3. Tokumaru, H. (2003) Nature conservation on Yakushima Island: Kagoshima Prefecture’s efforts. Global Environmental Research, 7(1): 103-111. Available at:  
   http://www.airies.or.jp/publication/ger/pdf/07-01-10.pdf
4. Kawaji, N. and Higuchi, H. (1989) Distribution and status of the Ryukyu Robin Erithacus komadori. Journal of the Yamashina Institute for Ornithology, 21(2): 224-233.
5. RSPB (July, 2002)
   http://www.rspb.org.uk/