Sandwich Tern

The Sandwich tern, Thalasseus sandvicensis, is a medium-large tern with a graceful profile, characterized by its grey upperparts and white underparts. A striking feature is its yellow-tipped black bill, complemented by a shaggy black crest during the breeding season, which recedes to reveal a white crown in winter. The young display a scalloped pattern on their backs and wings, with hues of grey and brown.

Identification Tips

Adult Sandwich terns can be identified by their slender black bills with a distinctive yellow tip and their pale grey upper wings. In flight, they appear particularly pale, with the exception of their primary flight feathers which darken over the summer. Juveniles can be recognized by the dark tips on their tails and the scaly pattern on their back and wings.

Habitat

This species is typically found along coasts and islands, and occasionally by large freshwater lakes near the coast.

Distribution

The Sandwich tern breeds across the Palearctic from Europe to the Caspian Sea and migrates to winter in South Africa, India, and Sri Lanka.

Behaviour

Sandwich terns are known for their dense and sociable breeding colonies. They nest in simple ground scrapes, laying one to three eggs. Their feeding technique involves plunge-diving for fish, primarily in marine environments. Courtship includes the male offering fish to the female.

Song & Calls

The Sandwich tern is quite vocal, emitting a loud grating call that can be transcribed as "kear-ik" or "kerr ink."

Breeding

Breeding occurs in dense colonies where the Sandwich tern lays its eggs in a ground scrape. The species is not overly aggressive in defending its nest, often relying on the proximity of more defensive species for protection.

Similar Species

The Sandwich tern could be confused with the lesser crested tern or the elegant tern, which have all-orange bills. The Chinese crested tern is very similar but has a yellow bill with a black tip and does not share its range with the Sandwich tern, making confusion unlikely.

Diet and Feeding

The diet consists mainly of fish, which are caught by skillful plunge-diving. This method of feeding is a spectacle in itself, as the terns dive directly into the water from flight.

Conservation Status

The Sandwich tern is classified as Least Concern by the IUCN, with an estimated global population of 460,000–500,000 individuals. It is subject to conservation actions under the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA).