Siberian Blue Robin (Oanh lưng xanh)

Conservation status: LC

This bird is a Siberian Blue Robin (Larvivora cyane). In Vietnamese, it is called Oanh Lưng Xanh.

Looking at the plumage in your photo, this appears to be either a female or a first-winter male.

Key Identification Features:

Upperparts: A subtle slate-blue or brownish-blue wash on the back and wings.
Underparts: Primarily white with a slightly buff or "dirty" greyish wash on the flanks and breast.
Face: A dark eye with a faint pale ring, and a relatively long, thin bill.
Behavior: As seen in your shot, they are ground-dwelling birds that enjoy foraging among fallen leaves in the forest undergrowth.

Photography Notes:

The Siberian Blue Robin is a migratory bird that visits Vietnam during the winter months. They are quite "skulking"—meaning they like to stay hidden in the shadows of the forest floor—so capturing one out in the open on the leaf litter like this is a great find.

Given the lighting and the background, it looks like another successful shot from your trip to a forested area like Nam Cat Tien!