Orange-billed tern

Cabot's, elegant, and royal terns in a mixed group in southwest Mexico

Orange-billed tern is a colloquial name applied to a group of four large terns in the genus Thalasseus with orange bills, which are quite similar in appearance and often considered difficult to identify, namely:

• Royal tern Thalasseus maximus
• West African crested tern Thalasseus albididorsalis
• Lesser crested tern Thalasseus bengalensis
• Elegant tern Thalasseus elegans

The greater crested tern (Thalasseus bergii) and the Cayenne tern (Thalasseus acuflavidus eurygnathus), which have yellow rather than orange bills, are also sometimes considered part of this group.

Identification

Identification of orange-billed terns within their core ranges is straightforward. Greater crested and Cayenne terns (which do not overlap in range) can be identified by their bill colour. Of the truly orange-billed species, the only core range geographical overlaps are between West African crested and lesser crested terns in western Africa, and between royal and elegant terns on the west coast of the Americas; in both cases the larger size and strong bill of royal and West African crested terns should prevent misidentifications (in addition, lesser crested terns have a grey, not white, rump).

Identification of vagrants has proved to be much more difficult however, with known hybridisation, and birds which do not match the classic character sets of individual species. See the references list below for more information.

References

• Millington, Richard & Gantlett, Steve (2002). The orange-billed tern in Norfolk. Birding World 15(6): 244-246.

This article documents a bird seen in Norfolk, England in summer 2002 which resembled both elegant and lesser crested terns to some degree; the article is accompanied by photos of this bird and a presumed elegant tern seen in a Florida tern colony in 2002.

• Millington, Richard (2002). The orange-billed terns in summer 2002. Birding World 15 (7): 287-290.

This article documents the 2002 influx into Britain, with discussion about the identification characters shown by each of the four or five birds, all of which are illustrated by photographs.

• Gantlett, Steve (2003). Identification of orange-billed terns. Birding World 16 (7): 285-304.

This article presents 51 captioned photographs of elegant, lesser crested and Cayenne terns, with an emphasis on "non-classic" individuals.

• Dufour, Paul; Pons, Jean-Marc; Collinson, J. Martin; Gernigon, Julien; Ignacio Dies, J.; Sourrouille, Patricia; Crochet, Pierre-André (2017). "Multilocus barcoding confirms the occurrence of Elegant Terns in Western Europe" (PDF). Journal of Ornithology. 158 (2): 351–361. doi:10.1007/s10336-016-1380-0. ISSN 2193-7192. Retrieved 2025-02-08.

This article documents the extralimital presence of elegant terns (including breeding) and a lesser crested tern in western Europe between 2001 and 2015, with genetic analysis confirming their identity.

• Stoddart, Andy, & Batty, Chris (2019). The Elegant Tern in Britain and Europe. British Birds 112 (2): 99–109.

This article documents the occurrence and identification of extralimital of elegant terns in western Europe.

• Ignacio Dies, J., Chardí, Miguel, & Abad, Ana (2019). Elegant Terns breeding at L'Albufera de Valencia, Spain. British Birds 112 (2): 110–117.

This article documents the breeding of pairs of elegant terns in a sandwich tern colony in Spain, fledging seven juveniles between 2009 and 2018.