Bridled TernOnychoprion anaethetusWhere and when to see them

The bridled tern is a graceful tropical seabird associated with offshore waters and rocky or vegetated islands. Its dark upperparts, white forehead and narrow white eyebrow create the facial pattern behind its English name. Compared with many beach-nesting terns, it often chooses sheltered nest positions beneath rocks or vegetation. In Seychelles it belongs to a diverse island seabird community, but colony access and seasonal attendance vary, making distant coastal watching the appropriate approach.

Size

30-32 cm long

Weight

100-150 g

Lifespan

Not reliably established

Status

Least Concern

Bridled terns forage with light, agile flight, dipping to take prey near the sea surface. They may gather around floating material or feeding predatory fish that make small prey accessible. At colonies, pairs occupy shaded spaces under ledges, roots or low vegetation rather than always nesting in exposed scrapes. Adults defend their immediate nest surroundings and alternate parental duties. Outside breeding, birds disperse more widely over tropical seas and can become less predictable near land. Courtship displays often involve aerial chases and fish offerings between mates. Unlike many other tern species, they are primarily nocturnal foragers, especially when feeding in moonlit conditions far offshore.

• Its white facial stripe gives it the appearance of wearing a bridle.
• A breeding attempt normally involves a single egg.
• Nests are often sheltered beneath rocks or vegetation.
• Birds sometimes use floating debris as resting platforms far offshore.

In Seychelles, breeding schedules differ among islands and may not follow one simple annual calendar. April to May and October to November often offer relatively manageable coastal conditions. Confirm current colony activity and access locally rather than treating these travel windows as a guaranteed nesting season. Breeding often occurs in synchronized colonies, which can present a spectacular viewing opportunity if timed correctly with local information. The specific timing of peak activity varies greatly between the inner granite islands and outer coral atolls.

Warm offshore waters provide feeding habitat, while small islands, rocky coastlines and coral cays offer nesting ground. Sheltered crevices and low coastal vegetation are especially useful at colonies. Birds may rest on floating objects at sea, sometimes well away from the nearest island. Bridled terns typically favor uninhabited islands or remote islets where they can nest free from human disturbance and terrestrial predators. Their affinity for coral cays highlights their reliance on healthy reef ecosystems in tropical regions.

Small schooling fish dominate the diet, supplemented by squid and marine invertebrates. Prey is usually taken from the surface or just below it. Associations with larger predatory fish can improve feeding opportunities, but these temporary gatherings are not dependable coastal viewing events. They often take advantage of feeding frenzies initiated by tuna or other large pelagic fish that drive schooling prey to the surface. This opportunistic feeding strategy allows them to conserve energy while efficiently acquiring food.

Common name

Bridled Tern

Scientific name

Onychoprion anaethetus

Animal group

Birds

Size

30-32 cm long

Weight

100-150 g

Lifespan

Not reliably established

Status

Least Concern

Identification

Compared with the larger, blacker sooty tern, the bridled tern has greyer-brown upperparts and a longer white eyebrow extending behind the eye. Note the dark cap extending to just below the eye and the prominent white forehead patch that forms a distinct V shape. In flight, their relatively long, slender wings and deeply forked tail are noticeable features.