Terek sandpiper 
(Choắt chân màng bé, Xenus cinereus) 

The Terek Sandpiper (Xenus cinereus, Choắt chân màng bé) is a small migratory wader species, family of Scolopacidae, genus Xenus. Terek Sandpiper is a pass-through winter bird commonly sighted at the Xuan Thuy National Park.

The bird breeds from Finland through northern Siberia to the Kolyma River, and migrates south in winter to tropical coasts in east Africa, south Asia and Australia.

The term Charadriiformes comes from New Latin, combining the Greek word kharadrios ("a bird of river valleys" or "a bird of ravines") and the Latin suffix -formes meaning "forms" or "shaped like". Therefore, Charadriiformes translates to "birds shaped like or resembling the charadrius," which is a type of plover or stone curlew historically found in dry river beds or ravines. 

The word Scolopacidae is New Latin, derived from the genus name Scolopax (Latin for "snipe" or "woodcock") and the common zoological suffix for family names, -idae.

The bird English name is named after the Terek River which flows into the west of the Caspian Sea where it was first observed.
The genus name Xenus is from Ancient Greek xenos meaning "stranger".
The specific epithet cinereus is Latin for "ash-grey" from cinis, cineris, "ashes".