Adult Bird:
The forehead is a dark, brownish-chestnut color. The remainder of the upperparts, including the wing coverts, are black with a bluish sheen. The flight feathers and tail feathers are black with a greenish sheen. All tail feathers, except the central ones, have a white mark on the inner web. The eyes are black. The chin, throat, and upper breast are a paler brownish-chestnut than the forehead. A broad, bluish-black band is present across the upper breast (occasionally, this band may be broken in the middle). The entire remaining underparts are white.
Juvenile Bird:
Generally resembles the adult bird, but the upperparts are a dark brown, and the outer tail feathers are shorter. The eyes are dark brown. The beak is black. The legs are black.
Measurements:
- Wing: 104 – 125 mm
- Tail (male): 64 – 106 mm; (female): 56 – 81 mm
- Tarsus: 9 – 10 mm
- Bill: 6 – 9 mm
Distribution:
This swallow species is distributed in eastern and northeastern regions of the Soviet Union, Japan, and Korea. In winter, it migrates south to India, Myanmar, Thailand, Indochina, Malaysia, Borneo, Java, Sumatra, and New Guinea. In Vietnam, it can be found in all regions, from the plains to the mountains.