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Thalasseus

Thalasseus
Sandwich tern
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Charadriiformes
Family: Laridae
Subfamily: Sterninae
Genus: Thalasseus
F. Boie, 1822
Type species
Sterna cantiaca
Gmelin, 1788[1] = T. sandvicensis (Latham, 1787)
Species

T. acuflavidus
T. albididorsalis
T. bengalensis
T. bergii
T. bernsteini
T. elegans
T. maximus
T. sandvicensis

Thalasseus, the crested terns, is a genus of eight species of medium-large to large terns in the family Laridae.

The species have a worldwide distribution in temperate and tropical seas, mostly between about 43° N and S latitude, but to 60° N in the warm waters of the North Atlantic Current in the eastern North Atlantic Ocean; they do not occur in colder arctic or antarctic waters. Several of the species are abundant and well-known birds in their ranges; one is however extremely rare and critically endangered. This genus had originally been distinguished by Friedrich Boie in 1822, but had been little used (with one exception in 1978[2]) until a 2005 study confirmed the need for a separate genus for the crested terns.[3]

All Thalasseus terns (here, an elegant tern) have long, slender wings, and tails where the outer feathers are somewhat longer than the inner feathers, but not as markedly so as in terns in the genus Sterna

Thalasseus terns are large for terns, from 35–53 cm long, with lesser crested tern marginally the smallest, and greater crested tern marginally the largest. The underside plumage is white in all species, while the wings and back vary from pale silvery grey to dark grey. They have long thin sharp bills, a shade of yellow or orange except in the Sandwich tern and Cabot's tern where the bills are black with yellow tips (variably more extensively yellow in one subspecies of Cabot's tern). All species have a shaggy black crest, which is erectile and used in the courtship display.[2] In winter, the foreheads become white to a variable extent. They breed in very dense colonies on coasts and islands, and exceptionally inland on suitable large freshwater lakes close to the coast. They nest in a ground scrape. Thalasseus terns feed by plunge-diving for fish, almost invariably from the sea. They usually dive directly, and not from the "stepped-hover" favoured by, for example, the Arctic tern. The offering of fish by the male to the female is part of the courtship display.

Their habit of breeding in very dense colonies made them highly vulnerable to the 2021–2023 highly pathogenic avian influenza (HPAI) outbreaks, with mass mortality in numerous colonies of Sandwich tern in particular.[4]

  1. ^ "Laridae". aviansystematics.org. The Trust for Avian Systematics. Retrieved 2023-07-26.
  2. ^ a b Tuck, Gerald S. (1978). A Field Guide to the Seabirds of Britain and the World. London: HarperCollins. pp. 117–119, 212–213. ISBN 0-00-219718-9.
  3. ^ Bridge, Eli S.; Jones, Andrew W.; Baker, Allan J. (2005). "A phylogenetic framework for the terns (Sternini) inferred from mtDNA sequences: implications for taxonomy and plumage evolution" (PDF). Molecular Phylogenetics and Evolution. 35 (2): 459–469. Bibcode:2005MolPE..35..459B. doi:10.1016/j.ympev.2004.12.010. PMID 15804415.
  4. ^ Knief, Ulrich; Bregnballe, Thomas; Alfarwi, Ibrahim; Ballmann, Mónika Z.; Brenninkmeijer, Allix; Bzoma, Szymon; Chabrolle, Antoine; Dimmlich, Jannis; Engel, Elias; Fijn, Ruben; Fischer, Kim; Hälterlein, Bernd; Haupt, Matthias; Hennig, Veit; Herrmann, Christof; in ‘t Veld, Ronald; Kirchhoff, Elisabeth; Kristersson, Mikael; Kühn, Susanne; Larsson, Kjell; Larsson, Rolf; Lawton, Neil; Leopold, Mardik; Lilipaly, Sander; Lock, Leigh; Marty, Régis; Matheve, Hans; Meissner, Włodzimierz; Morrison, Paul; Newton, Stephen; Olofsson, Patrik; Packmor, Florian; Pedersen, Kjeld T.; Redfern, Chris; Scarton, Francesco; Schenk, Fred; Scher, Olivier; Serra, Lorenzo; Sibille, Alexandre; Smith, Julian; Smith, Wez; Sterup, Jacob; Stienen, Eric; Strassner, Viola; Valle, Roberto G.; van Bemmelen, Rob S. A.; Veen, Jan; Vervaeke, Muriel; Weston, Ewan; Wojcieszek, Monika; Courtens, Wouter (2024). "Highly pathogenic avian influenza causes mass mortality in Sandwich Tern Thalasseus sandvicensis breeding colonies across north-western Europe" (PDF). Bird Conservation International. 34. Cambridge University Press (CUP). doi:10.1017/s0959270923000400. ISSN 0959-2709. Retrieved 2025-01-14.

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Thalasseus AF ثالاسوس ARZ Krepay (Thalasseus) AVK Kəkilli susüpürən AZ Thalasseus BR Thalasseus Catalan Thalasseus CEB Thalasseus Danish Thalasseus German Thalasseus EO

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