
Photo: (c) William Stephens, some rights reserved (CC BY) · CC BY 4.0 (May be cropped or resized)
Nannus troglodytes
Also known as: Troglodytes troglodytes
Rare visitor: recorded only occasionally in this country
Eurasian Wren (Troglodytes troglodytes) is a tiny russet-brown bird with fine dark barring, a pale eyebrow, thin bill and very short tail commonly held upright. Body shape, bill structure, plumage pattern and voice provide the strongest field characters. Age, sex and season may alter its appearance, so identification should combine several features and careful direct field comparisons with similar species in the same habitat (Wikipedia, general species account).
It inhabits dense undergrowth, rocky places and woodland across the Palearctic, searching crevices for insects and spiders and producing a remarkably loud song from low cover. Its movements and social behaviour vary through the year, with breeding birds generally more dispersed and non-breeding birds gathering where food is concentrated. The Korean vertebrate catalogue used for this guide records the species in South Korea (Wikipedia, general species account; Wildlife of Korea occurrence records).