Description:
The bird measures 32 cm in length, with a 5 cm tail. It flies gracefully, gliding and diving into the water, often immersing itself. The upper back is pale gray, with dark edges on the primary feathers’ outer margins and light-colored inner margins (visible from below). The belly is gray. There are two subspecies: tibertana with a black beak, a dark red base extending to the lower mandible, and scarlet legs; and longipennis with a black beak and light black legs.
Outside the breeding season, the forehead is white. The wingtips have dark markings, and the contrasting white and gray colors are clearly visible during flight, similar to the Aleutian Tern (Onychoprion aleuticus). Juveniles are dark brown and brown, except for the upper body. During flight, a light black wing corner and dark edging of the primary feathers on the upper wing surface are visible.
Distribution:
Northeastern Vietnam (coastal areas of the Red River Delta) and Southern Vietnam.
Status:
Migratory. Common.
Habitat:
Coastlines, rivers, lakes, and coastal marshes.