Thalasseus

Taxobox
name = "Thalasseus"

---

image_width = 250px
image_caption = Sandwich Tern
regnum = Animalia
phylum = Chordata
classis = Aves
ordo = Charadriiformes
familia = Sternidae
genus = "Thalasseus"
genus_authority = Boie, 1822
subdivision_ranks = species
subdivision = "T. bengalensis"
"T. maximus"
"T. bergii"
"T. bernsteini"
"T. elegans"
"T. sandvicensis"

"Thalasseus", the crested terns, is a genus of six species of seabirds in the tern family. It has a world-wide distribution, and many of its species are abundant and well-known birds in their ranges. This genus had originally been created by Heinrich Boie in 1822, but had been abandoned until a 2005 study confirmed the need for a separate genus for the crested terns.cite journal|last=Bridge |first=Eli S. |coauthors= Jones, Andrew W. & Baker, Allan J.|year=2005 |title= A phylogenetic framework for the terns (Sternini) inferred from mtDNA sequences: implications for taxonomy and plumage evolution | url = http://www.cmnh.org/site/Files/Ornithology/MPETerns.pdf| format = PDF| doi=10.1016/j.ympev.2004.12.010 | journal=Molecular Phylogenetics and Evolution | volume=35 |pages=459–469]

These large terns 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.

These species have long thin sharp bills, usually a shade of yellow or orange except in the Sandwich Tern where the bill is black with a yellow tip in most subspecies. All species have a shaggy crest. In winter, the "Thalasseus" terns' foreheads become white.

List of species in taxonomic order

* Lesser Crested Tern "Thalasseus bengalensis"
* Royal Tern "Thalasseus maximus"
* Greater Crested Tern or Swift Tern, "Thalasseus bergii"
* Chinese Crested Tern "Thalasseus bernsteini"
* Elegant Tern "Thalasseus elegans"
* Sandwich Tern "Thalasseus sandvicensis"

An early Pliocene fossil bone fragment from the northeastern United States closely resembles a modern Royal Tern. It may be an unexpectedly early (3.7–4.8 million years before present) specimen of that species, or an ancestral member of the crested tern group. Olson, S., Rasmussen, P.C., "Miocene and Pliocene birds from the Lee Creek Mine, North Carolina" in Ray, C. E. & Bohaska, D. J. (2001). "Geology and Paleontology of the Lee Creek Mine, North Carolina, III." "Smithsonian Contributions to Paleobiology", 90. Smithsonian Institution Press, Washington D.C. 233–365.]

References

* Harrison, Peter "Seabirds: An Identification Guide" ISBN 0-7470-1410-8
* Olsen and Larsson, "Terns of Europe and North America" ISBN 0-7136-4056-1