North American birds migrate to southern coasts, the West Indies and northernmost South America.

[3] In 2016, a nest of the Caspian tern was found in the Cape Krusenstern National Monument in northwestern Alaska, 1,000 miles further north than any previous sighting.

This development was part of a general trend in Alaska of species moving to the north, a tendency ascribed to global warming.

[3][9] The Caspian tern is one of the species to which the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA) applies.

[3][7] Breeding is in spring and summer, with one to three pale blue-green eggs, with heavy brown spotting, being laid.