Black-naped Tern

Overview

The black-naped tern (Sterna sumatrana) is an oceanic tern predominantly found in tropical and subtropical regions of the Indian Ocean and western Pacific Ocean. It is rarely encountered inland and is classified as Least Concern on the IUCN Red List.

Identification

• Distinctive black band extending from the eyes around the back of the head and down the nape.
• White plumage on the body with pale silvery-grey wings and mantle, and a deeply forked white tail that extends beyond the wingtips when perched.
• Black beak and legs, with a body length of 30–35 cm.
• Calls consist of short, high-pitched, repeated sharp notes described as 'chit', 'chip', 'chrrut', or 'tsip'.

Habitat

This species inhabits rocky shores throughout the Western Pacific and Indian Oceans, ranging from the western Indian Ocean to Taiwan in the north and Queensland in the south. It migrates annually to islets and islands to serve as breeding grounds, where it nests in small colonies on rocky outcrops or in depressions above high tide levels.

Diet

Feeding primarily by diving and partially breaching the water surface to capture prey, the black-naped tern consumes small fish up to 10 cm in length, including hardyheads, sprats, anchovies, garfish, flying fish, mullet, barracudas, trevally, and tuna. While most hunting occurs alone at sea, pairs hunt closer to shore in the surf when provisioning nestlings and mates.

Did you know?

To protect their chicks from gull predation until the young reach a weight of roughly 65 g, parents camouflage the nest by removing eggshell remnants and defecating several metres away to prevent bright materials from attracting attention. On one recorded occasion, a colony used shrill cries, mobbing, and defecation as a defence mechanism against an encroaching grey heron.