Siberian Thrush Geokichla sibirica Scientific name definitions

20·5–23 cm; 60–72 g. Male nominate race is bluish-slaty, darker on face and shoulders, with long white supercilium , white belly, and white tips of undertail-­coverts and outer tail; bill blackish; legs yellow. Female is olive-tinged mid-brown above, with mid-brown crown and wings, buffy-tipped wing-coverts, buff-and-brown face pattern, buff-and-brown scaling below, with white tips of undertail-coverts and outer tail. Immature male resembles adult male, but whitish on submoustachial and throat, pale buff tips of greater coverts, paler with whitish spotting below; immature female very like adult female, but wing spots stronger, face definition weaker, markings below heavier. Race <em>davisoni</em> is larger than nominate, male blacker, with vestigial white tips of undertail-coverts and tail, female darker olive-brown.

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Editor's Note: Additional distribution information for this taxon can be found in the 'Subspecies' article above. In the future we will develop a range-wide distribution article.

Migratory. Departs from breeding areas early Sept to mid-Oct, with extensive passage through E China early Sept, but around Beidaihe (NE China) commoner in spring and very few records in autumn (mainly Sept); similar situation in N Korea, where records mid-Sept to late Oct. Scarce passage migrant and winter visitor in Hong Kong, commoner in autumn (late Sept to late Nov) than in spring (late Mar to late Apr), but this pattern reversed in 1995. Only on passage in Thailand, unless wintering in mountains in S. In Peninsular Malaysia a passage migrant and winter visitor mid-Oct to late Apr (autumn passage extending to early Dec). Regular in winter in Sumatra and W Java, but rare in Borneo and Bali. Vagrant to the Philippines (Luzon, Feb 2012) (2 Jensen, A. E., T. H. Fisher, and R. O. Hutchinson (2015). Notable new bird records from the Philippines. Forktail 31:24–36. Close ). Occasional winterer in NE India. Spring return starts late Mar, with flocks of 60 in Apr in Myanmar; arrival in N Japan (race davisoni) late Apr to early May, but continuing passage through NE China and N Korea mid-Apr to late May, and arrival in Mongolia late May to early Jun. Vagrants recorded annually in Europe, rarely in small flocks.

Invertebrates, chiefly worms, and fruit, including fallen figs. Commonly terrestrial , but sometimes visits fruiting trees; usually in parties.

Song, typically by male from high in tree, a prolonged series of spaced-out, languid, rich but also rather hesitant, short phrases, “tvee-tring tvee-tryu tvee-kvee tvee-kwi-tring yui’i-tss” and so on; race davisoni less musical, more squawky and abrupt, “feep-tss tweet-tss kleep-tsss”. Calls include thin quiet “tsit” and “tsip” for contact, stronger “seep” or “tseee” when flushed and on migration, and soft dry rattling “chrssss” in alarm.

May–Jul in China and Japan; Jun–Jul in C Siberia. Nest a cup of small twigs, tendrils and bark, lined with moss, leaves and rootlets, bound with some mud, placed above 1 m from ground (rarely higher than 4·5 m) in concealed position in small tree or crotch of shrub in undergrowth. Eggs 4–5 (3–4 in Japan), bluish with brown spotting; incubation period 11 days. In a study in C Siberia, mean clutch 4·86 (n = 95), incubation period c. 10 days, nestling period 10–11 days (3 Demidova, E.Y. (2011). Reproductive parameters of four thrush species of Central Siberia. Biology Bulletin 38(5): 509–517. Close ).

Not globally threatened (Least Concern). Rare to locally abundant in Russia; fairly common in China. Locally common in Japan on Hokkaido and N & C Honshu; rare breeder in Kuril Is. Numbers in Japan severely reduced by trapping in first half of 20th century. Uncommon migrant in Thailand, but common in montane Peninsular Malaysia on passage and in winter.