Justification of Red List Category
This thrush has a small, rapidly declining population as a result of high levels of nest-predation by introduced species, probably compounded by habitat loss. It therefore qualifies as Vulnerable.
The global population is estimated to be in the band c.2,500-9,999 mature individuals (BirdLife International 2001), equivalent to 3,750-14,999 individuals, rounded here to 3,500-15,000 individuals. The population in Japan has been estimated at c.100-10,000 breeding pairs (Brazil 2009).
On islands affected most heavily by introduced predators, population declines have been rapid; for example surveys on Miyake-jima showed declines from 24.4, 23.4 and 33.3 individuals per km in 1978-1980, to 6.7 and 11.1 individuals per km in 1990-1991. These results suggest a rapid decline is likely to be occurring across the population.
Turdus celaenops is endemic to Japan. The majority of the population is resident on the Izu Islands between Oshima and Aogashima, but a few birds move to adjacent parts of Honshu and the Shikoku Islands during winter. There are also small numbers on the islands of Yaku-shima and Tokara in the northern Nansei Shoto Islands. Given that the total area of the Izu Islands is only c.300 km2, it is unlikely that the population ever exceeded more than a few thousand individuals and it is now declining rapidly.
It inhabits deciduous woodlands with a well developed canopy and sparse shrub layer, avoiding understoreys with bamboo. On Yaku-shima, it occurs in mixed juniper-rhododendron forest. It also feeds outside forest along roadsides, in ploughed fields and undisturbed gardens, foraging for fruit, seeds and, in summer, mainly invertebrates.
Nest-predation by Siberian weasels Mustela sibirica, Large-billed Crow Corvus macrorhynchos and domestic cats is the main threat. Its population on Miyake-jima declined rapidly following the introduction of Siberian weasels in the 1970s. The population of Large-billed Crow on Mikake-jima and the other Izu Islands has increased as a result of the dumping of raw garbage. During a survey on Miyake-jima in 1992, a total of 22 nests were found containing eggs, all of which hatched, but all nestlings were subsequently predated. The effects of predation are likely to have been compounded by habitat loss, associated with timber production, tourist developments and road construction. Volcanic eruptions on Miyake-jima in 2000 had a negative effect on the population on that island (Y. Yamamoto in litt. 2012).
Conservation Actions Underway
It is legally protected in Japan. The entire Izu Archipelago has been designated as a national park and several important sites as Special Protected Areas. There is a small sanctuary on Miyake-jima. A recent awareness campaign has been carried out (Y. Yamamoto in litt. 2012).
23 cm. Medium-sized, strikingly patterned thrush. Male has black head and upper breast, rich orange-red breast, flanks and white centre of belly. Dark brown upperparts. Female has rich brown head and white throat with black streaks. Similar spp. Brown Thrush T. chrysolaus male has olive-brown head with darker throat and orange-red top of breast. Female has indistinct pale supercilium and pale throat streaked brown.
Text account compilers
Derhé, M., Khwaja, N., Benstead, P., North, A., Gilroy, J.
BirdLife International (2021) Species factsheet: Turdus celaenops. Downloaded from http://www.birdlife.org on 23/04/2021. Recommended citation for factsheets for more than one species: BirdLife International (2021) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 23/04/2021.