Red-flanked Bluetail

The red-flanked bluetail, also called the orange-flanked bush-robin, is a small Old World flycatcher, 13–14 cm long and 10–18 g. It breeds in mixed coniferous forests with undergrowth in northern Asia, parts of Central Asia and north-eastern Europe, from northern Sweden east across Siberia to Kamchatka and south to Japan. It is migratory, wintering mainly in south-east Asia, the Indian subcontinent, the Himalayas, Taiwan and northern Indochina. (Wikipedia, general species account)

Both sexes have a blue tail and rump and orange-red flanks, a white throat and greyish-white underparts. The adult male also has dark blue upperparts, while females and immature males are plain brown above apart from the blue rump and tail. The nest is built on or near the ground and the 3–5 eggs are incubated by the female. The breeding range is slowly expanding westward through Finland, and it is a rare but increasing vagrant in western Europe. (Wikipedia, general species account)