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Amami Thrush Zoothera major



Justification

Justification of Red List Category
The population size is likely increasing in this species. However, it is restricted to a very small range, and is likely found in only a limited number of locations. Therefore, it is listed as Near Threatened.

Population justification
Based on detection rate analysis, the species was estimated to have a population size of 2,513 mature individuals in 2013 (Mizuta et al. 2016). Therefore, the population is tentatively placed in the range of 2,500-9,999 mature individuals.

Trend justification
The population size is likely increasing. Based on a 1996 estimate the population size was reported as 58 mature individuals (Amami Ornithologists’ Club [AOC] 1997). The population appears to have been showing a gradual recovery with 502 singing birds recorded during surveys in 2013 (Mizuta et al. 2016). However no attempt was made to extrapolate to the full extent of suitable habitat, and doing so indicated that the population was actually 945-1,858 prior to 2012 (Mizuta et al. 2016). Detection rate (birds per point count) between 2007 and 2012 was roughly similar at approx. 1.2, but the 2013 survey returned 1.7 birds per point. The increased detection of birds in 2013 indicated the population may be 2,513 mature individuals in that year (Mizuta et al. 2016).

Distribution and population

Zoothera major is endemic to the islands of Amami-ooshima and Kakeroma-jima in the northern Nansei Shoto Islands, Japan. On Amami-ooshima, it has only been recorded from the central and western parts of the island and it may be extinct on Kakeroma-jima.

Ecology

It is confined to mature (over 60 years old) subtropical broadleaved evergreen forest around humid valleys at altitudes of 100-400 m. A shy bird, it is often found near moss-covered rocks by forest streams. The diet includes invertebrates and fruit. Breeding is in May and June, when it nests on low branches c.1.5-3 m above the ground, laying clutches of 3-4 eggs.

Threats

The main threat is the clearance of the mature broadleaved forest which only covers 10-15 km2 of Amami-ooshima, less than 5% of the island's area. The apparent population declines during the 1990s are thought to have been caused by clear-felling of forest. Predation by the Javan mongoose Herpestes javanicus, which was introduced for snake control, may also have contributed to its decline.

Conservation actions

Conservation Actions Underway
It is legally protected in Japan. Yuwanga-take National Wildlife Protection Area, on Amami-ooshima, was established primarily for the conservation of this species and Lidth's Jay Garrulus lidthi. Two prefecture protected areas, Kanengo-take and Kinsaku-baru, have also been established on Amami-ooshima.

Conservation Actions Proposed
Prevent further logging of mature forest on Amami-ooshima and allow areas of medium-aged forest to develop into mature forest. Ensure the conservation of the few remaining areas of mature forest in the central and western parts of Amami-ooshima. Control introduced predators. Monitor the status of the population on Amami-ooshima. Survey Kakeroma-jima to see if it remains extant and, if it does, develop appropriate conservation measures.

Identification

30 cm. Large, heavily patterned thrush. Warm olive-brown to buff upperparts and whitish underparts with heavy black scaling. Twelve tail feathers. Similar spp. White's Thrush Z. dauma is smaller and has 14 tail feathers. Voice Cheerful song, mostly delivered in morning and similar to Siberian Thrush Z. sibirica. Z. dauma has more mournful song, often delivered at night.

Acknowledgements

Text account compilers
Benstead, P., Martin, R & Westrip, J.


Recommended citation
BirdLife International (2019) Species factsheet: Zoothera major. Downloaded from http://www.birdlife.org on 15/11/2019. Recommended citation for factsheets for more than one species: BirdLife International (2019) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 15/11/2019.