Terns (Sternidae)

Sandwich Tern (Thalasseus sandvicensis) - HBW 3, p. 647

French: Sterne caugek German: Brandseeschwalbe Spanish: Charrán Patinegro
Other common names: Yellow-nibbed Tern; Cabot's Tern (acuflavidus); Cayenne Tern (eurygnatha)

Taxonomy: Sterna Sandvicensis Latham, 1787, Sandwich, Kent, England.
Genus often merged with Sterna. Forms superspecies with T. elegans and T. bengalensis, and perhaps also T. bernsteini, and it has been suggested that all may even be conspecific. Form eurygnatha, Cayenne Tern, generally considered separate species until work in S Caribbean showed it to be race or possibly morph of T. sandvicensis, and that all but northernmost New World populations have at least small percentage of “Cayenne”-type birds. Races acuflavidus and eurygnatha interbreed freely in S Caribbean, and mixed pairs occur also in P.. View all taxonomy...

Taxonomy: Sterna Sandvicensis Latham, 1787, Sandwich, Kent, England.
Genus often merged with Sterna. Forms superspecies with T. elegans and T. bengalensis, and perhaps also T. bernsteini, and it has been suggested that all may even be conspecific. Form eurygnatha, Cayenne Tern, generally considered separate species until work in S Caribbean showed it to be race or possibly morph of T. sandvicensis, and that all but northernmost New World populations have at least small percentage of “Cayenne”-type birds. Races acuflavidus and eurygnatha interbreed freely in S Caribbean, and mixed pairs occur also in Patagonia and Puerto Rico; possibility of assortative mating deserves further study. In Curaçao typical acuflavidus make up 20% of population, while in French Guiana they comprise less than 1%. Three subspecies currently recognized.

Subspecies and Distribution:

  • sandvicensis (Latham, 1787) - Europe E to Caspian Sea; winters from Caspian, Black and Mediterranean Seas to coasts of W & S Africa, and from S Red Sea to NW India and Sri Lanka.
  • acuflavidus (Cabot, 1848) - E North America (Virginia locally to Campeche Bank and Belize), and through Antilles to S Caribbean; winters from Caribbean S to S Peru and Uruguay.
  • eurygnatha (Saunders, 1876) - highly local breeder in Caribbean, off Venezuela and French Guiana (Cayenne), and from E Brazil to S Argentina (Buenos Aires, and Patagonia from Chubut to Santa Cruz).