The royal tern (Thalasseus maximus) is a tern in the family Laridae. The species is endemic to the Americas, though vagrants have been identified in Europe.
Taxonomy
The royal tern was described by the French polymath Georges-Louis Leclerc, Comte de Buffon in 1781 in his Histoire Naturelle des Oiseaux from a specimen collected in Cayenne, French Guiana. The bird was also illustrated in a hand-colored plate engraved by François-Nicolas Martinet in the Planches Enluminées D'Histoire Naturelle which was produced under the supervision of Edme-Louis Daubenton to accompany Buffon's text. Neither the plate caption nor Buffon's description included a scientific name but in 1783 the Dutch naturalist Pieter Boddaert coined the binomial name Sterna maxima in his catalogue of the Planches Enluminées. The royal tern is now placed in the genus Thalasseus that was erected by the German zoologist Friedrich Boie in 1822.
The generic name is derived from the Ancient Greek (thálassa) meaning "sea". The specific epithet maximus is Latin for "greatest".
The royal tern belongs to the class Aves and the order Charadriiformes. Charadriiformes includes seabirds and shorebirds of small to medium-large size. Within Charadriiformes, it is placed in the family Laridae, subfamily Sterninae, because of its white plumage, a black cap on its head, long bill, webbed feet, and bodies that are more streamlined than those of gulls.
The taxonomy of the royal tern has been debated, whether the correct scientific name was Thalasseus maximus or Sterna maxima. It was originally placed in the genus Sterna; however, a 2005 study found that the genus Thalasseus is genetically distinct from Sterna; after genetic data showed that West African crested tern is more closely related to lesser crested tern than it is to royal tern.
Description
This is a large tern, second only to the Caspian tern among terns in the Americas, but is unlikely to be confused with this "carrot-billed" giant, which has extensive dark underwing patches. Adults have an average wingspan of for both sexes, with a range from . Its bill-to-tail length ranges from and the weight is anywhere from .
The royal tern has a stout orange-red bill, pale silvery-gray upperparts, and white underparts. Its legs are black. The entire crown is black with a shaggy, erectable crest on the nape in the spring during courtship and the start of the breeding season. From early summer into late winter, the black becomes first patchy and then fully white on the forehead and upper crown, retaining black only on the nape. Compared to elegant tern, its molt out of breeding plumage is about two months earlier (June, versus August, for northern populations), and more extensively white. The wintering range in the east is from North Carolina south to Panama and the Guianas and throughout the Caribbean. The western population nests from California to Mexico and winters from California south to Peru. Argentinian breeders are resident or disperse into Brazil.