Sandwich tern – Thalasseus sandvicensis
This is a medium-large tern, 37–43 cm (15–17 in) long with an 85–97 cm (33–38 in) wingspan, which is unlikely to be confused within most of its range, although the South American race could be confused with the elegant tern. The Sandwich tern’s thin sharp bill is black with a yellow tip, except in the yellow or orange billed South American race. Its short legs are black. Its upperwings are pale grey and its underparts white, and this tern looks very pale in flight, although the primary flight feathers darken during the summer. They are relatively common on Gotland which is nice.

The Sandwich tern has an extensive global range estimated at 100,000–1,000,000 km² (39,000–386,000 sq mi). It has a population estimated at 460,000–500,000 individuals. Population trends have not been quantified, but the species is not believed to approach the thresholds for the population decline criterion of the IUCN Red List (i.e., declining more than 30% in ten years or three generations). For these reasons, the species is evaluated as least concern.

The Sandwich tern is among the taxa to which the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA) applies. Parties to the agreement are required to engage in a wide range of conservation actions which are describes in a detailed action plan. This plan should address key issues such as species and habitat conservation, management of human activities, research, education, and implementation.

Listen to the typical harsh call
Recording by Jarek Matusiak from Xeno-canto