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Thalasseus maximus

(Boddaert, 1783)

Royal Tern

G5Secure Found in 1 roadless area NatureServe Explorer →
G5SecureGlobal Rank
Least concernIUCN
Identity
Unique IDELEMENT_GLOBAL.2.1168678
Element CodeABNNM08180
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVertebrate Animal
IUCNLeast concern
Endemicoccurs (regularly, as a native taxon) in multiple nations
KingdomAnimalia
PhylumCraniata
ClassAves
OrderCharadriiformes
FamilyLaridae
GenusThalasseus
Synonyms
Sterna maximaBoddaert, 1783
Other Common Names
Charrán Real (ES) Sterne royale (FR) Trinta-Réis-Real (PT)
Concept Reference
American Ornithological Society (AOS). Chesser, R. T., S. M. Billerman, K. J. Burns, C. Cicero, J. L. Dunn, A. W. Kratter, I. J. Lovette, N. A. Mason, P. C. Rasmussen, J. V. Remsen, Jr., D. F. Stotz, and K. Winker. 2020. Sixty-first Supplement to the American Ornithological Society’s Check-list of North American Birds. The Auk 137(3):1-24.
Taxonomic Comments
Formerly (e.g., AOU 1983, 1998) considered conspecific with T. albididorsalis (Hartert, 1921) [West African Crested Tern], but separated based on genetic data that indicate that T. albididorsalis is sister to T. bengalensis (Lesson, 1831) [Lesser Crested Tern] (Collinson et al. 2017), and differences in vocalizations and morphology (summarized in Dufour and Crochet 2020) (AOS 2020). Formerly (AOU 1983, 1998) included in the genus Sterna but separated on the basis of genetic data that correspond to plumage patterns (Bridge et al. 2005).
Conservation Status
Rank MethodExpertise without calculation
Review Date2016-04-10
Change Date1996-11-27
Edition Date1988-04-21
Range Extent20,000-2,500,000 square km (about 8000-1,000,000 square miles)
Rank Reasons
Large range; relatively stable populations in major nesting reagion in the southeastern U.S. Sensitive to disturbance when nesting.
Range Extent Comments
This species breeds locally on Pacific coast in southern California (rarely, not in recent years) and western Mexico (coast of Sonora and Sinaloa, Tres Marias Islands); Gulf coast and Maryland south through West Indies (where breeding irregular in location, year, and number of pairs; van Halewyn and Norton 1984) to northern South America (northern Venezuela and nearby islands, French Guiana), including cays in Puerto Rico and Virgin Islands; Uruguay coast and northern Argentina. Possibly 80% of the world population breeds in the southeastern U.S. Nonbreeders occur in summer north to central California and New York, south through winter range (rare on Pacific coast south of Mexico). It winters north to central California, Gulf coast, and North Carolina, south along coasts to Peru, Uruguay, and Argentina.
Threat Impact Comments
Routinely deserts colony en masse and moves to new site if disturbed early in egg-laying period (Buckley and Buckley 1984).
Ecology & Habitat

Description

A large tern with a moderately thick orange-red bill, grayish flight feathers, white underparts, and a moderately forked tail; adult has black cap in breeding season; immature and adults in basic plumage have a white crown and black nape (black generally does not include eye); average length 51 cm, wingspan 104 cm (NGS 1983).

Diagnostic Characteristics

Differs from the caspian tern in having a thinner bill, underside of primaries mostly pale (vs. dark), a more deeply forked tail, and, in basic and immature plumages, a white crown and forehead (vs. dusky). Differs from elegant tern in larger size (average length 51 cm vs. 43 cm), thicker bill, less slender body, and (in nonbreeding plumage) usually lack of dark feathering contacting the eye. Averages at least 12 cm longer than other North American terns.

Habitat

Seacoasts, lagoons, estuaries, rarely on lakes (AOU 1983). Loafs and sleeps on mudflats, sandspits, or salt-pond dikes (Stiles and Skutch 1989).

Nests typically on open sandy beaches of barrier islands, sandbars, sand/shell substrates; also on newly created dredged-material islands (Spendelow and Patton 1988); on remote cays in Puerto Rico and Virgin Islands. Colony site requirements: absence of quadruped predators; isolation from disturbance, combined with excellent visibility; proximity to areas of extensive shallows; and proximity to oceanic inlets (Buckley and Buckley 1984). Colonies in the eastern U.S. regularly change location (Buckley and Buckley 1984).

Ecology

Nonbreeding: often in large flocks when resting on land; often in large mixed flocks when migrating.

Reproduction

Lays clutch of usually 1 egg, May-June in southeastern U.S. and Puerto Rico/Virgin Islands, April-June in Texas. Incubation lasts 20-22 days (reported also as 28-35 days), by both sexes. Young are tended by both parents, flock with other young at 2-3 days, fly at 4-5 weeks. Usually nests in dense colony; colony size commonly over 1000 in most areas in U.S., some colonies >10,000 in South Carolina, Texas, and Louisiana (Spendelow and Patton 1988).
Terrestrial Habitats
Sand/dune
Other Nations (1)
United StatesN5B,N5N
ProvinceRankNative
South CarolinaS4Yes
MarylandS1BYes
North CarolinaS4B,S4NYes
New JerseyS4Yes
MassachusettsS1NYes
New MexicoSNRYes
MississippiS1B,S4NYes
TexasS4BYes
DelawareSNAYes
VirginiaS1BYes
GeorgiaS5Yes
FloridaS3Yes
New YorkSNRNYes
ConnecticutSNAYes
LouisianaS5Yes
CaliforniaSNRNYes
AlabamaS2B,S5NYes
Rhode IslandS1NYes
Roadless Areas (1)
California (1)
AreaForestAcres
Malduce BuckhornLos Padres National Forest14,177
References (35)
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  2. American Ornithologists' Union (AOU). 1983. Check-list of North American Birds, 6th edition. Allen Press, Inc., Lawrence, Kansas. 877 pp.
  3. American Ornithologists' Union (AOU). 1998. Check-list of North American birds. Seventh edition. American Ornithologists' Union, Washington, D.C. [as modified by subsequent supplements and corrections published in <i>The Auk</i>]. Also available online: http://www.aou.org/.
  4. American Ornithologists' Union (AOU). 2006. Forty-seventh supplement to the American Ornithologists' Union Check-list of North American Birds. The Auk 123(3):1926-936.
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