Bridled Tern

The Bridled Tern, Onychoprion anaethetus, is a robust seabird of the tropical oceans, with a medium build, measuring 30–32 cm in length and boasting a wingspan of 77–81 cm. Its upperparts are a dark grey, while the underparts remain a stark white. A distinctive white collar graces the hindneck, complementing the white forehead and eyebrows. The species is equipped with black legs and a bill of the same hue, and its wings and deeply forked tail are notably elongated.

Identification Tips

When observing the Bridled Tern, look for its long wings and deeply forked tail, which are characteristic of the species. The dark grey upperparts contrast with the white underparts, and the white collar on the hindneck is quite striking. The bird's black legs and bill are also key identification features. Juveniles display a scaly grey pattern above and are paler below.

Habitat

The Bridled Tern is a bird of the tropical oceans, exhibiting a strong preference for marine environments.

Distribution

This migratory and dispersive bird winters across the tropical oceans. It is found in various regions, with the Atlantic subspecies melanopterus breeding in locales such as Mexico, the Caribbean, and West Africa. Other populations are seen around the Arabian Peninsula, Southeast Asia, and Australasia. The Bridled Tern is also a rare vagrant to western Europe.

Behaviour

The Bridled Tern is known for its marine habits, which are more pronounced than most terns. It engages in plunge-diving for fish, a common feeding method, but will also pick food from the surface. Unlike the Arctic tern, it typically dives directly without the "stepped-hover" technique. Courtship displays include the male offering fish to the female.

Breeding

Colonies of Bridled Terns breed on rocky islands, where they nest in ground scrapes or holes and lay a single egg.

Similar Species

The Bridled Tern could potentially be confused with the similarly dark-backed Sooty Tern or the Spectacled Tern from the Tropical Pacific. However, it is paler-backed than the Sooty Tern, with a narrower white forehead and a distinct pale neck collar.

Diet and Feeding

The diet of the Bridled Tern consists primarily of fish, which it captures through plunge-diving and surface picking in marine settings.

Conservation status

The Bridled Tern is currently listed as Least Concern on the IUCN Red List, indicating that it is not at immediate risk of population decline.