Thalasseus maximus
Silhouette: Andy Wilson · PhyloPic
In 3 days ~50% in a week ~80%
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. 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 θάλασσα (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... Wikipedia →
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Havana | 🇨🇺 Cuba | |
| 2 | San Diego | 🇺🇸 United States | |
| 3 | Montevideo | 🇺🇾 Uruguay | |
| 4 | Miami | 🇺🇸 United States | |
| 5 | Panama City | 🇵🇦 Panama | |
| 6 | Tijuana | 🇲🇽 México | |
| 7 | Santo Domingo | 🇩🇴 Dominican Republic | |
| 8 | Los Angeles | 🇺🇸 United States | |
| 9 | Vitória | 🇧🇷 Brazil | |
| 10 | Barranquilla | 🇨🇴 Colombia |
| # | Zoo / Centre | Country | |
|---|---|---|---|
| 1 | Downtown Aquarium, Denver | 🇺🇸 United States |
Possible
About 20% of wildlife watchers report a Royal Tern sighting in Sian Ka'an Biosphere Reserve on a given day, based on 601 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 63rd most-seen of the 288 birds we can rate there. Over three days the chance rises to about 50%, and over a week to about 80%, if each day is a fresh chance.
February
In that month about 40% of wildlife watchers report a Royal Tern in Sian Ka'an Biosphere Reserve on a given day, against about 10% in June to August, the lowest months. That is one of Sian Ka'an Biosphere Reserve's driest months, with about 35 mm of rain against 230 mm in June.
Between 7 and 10 am
Across all the parks we cover, that three-hour window holds the most Royal Tern sightings with a recorded time, and about 9 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
18th of 42
Of the 42 parks where we can rate Royal Tern sightings, Sian Ka'an Biosphere Reserve ranks 18th at about 20%. The best odds are in Padre Island National Seashore (United States, about 80%), Ría Lagartos Biosphere Reserve (Mexico, about 80%) and Jaragua National Park (Dominican Republic, about 50%). All parks ranked.
GBIF citizen-science records
It is estimated from how often the Royal Tern is recorded against all the birds logged in Sian Ka'an Biosphere Reserve (601 verified sightings from 2019 to 2026), calibrated against known sighting rates. Figures are rounded to the nearest 10% because citizen-science data supports honest approximations, not decimals, and months with records from fewer than five people show "—". How it works.
