Thalasseus elegans
Silhouette: JJ Harrison (vectorized by T. Michael Keesey) · PhyloPic
In 3 days ~20% in a week ~30%
The elegant tern (Thalasseus elegans) is a tern in the family Laridae. It breeds on the Pacific coast of southern California in the United States and western Mexico, and migrates south to Peru, Ecuador and Chile for the northern winter; in the late summer and fall, some also disperse north to Oregon and more rarely Washington.
This species breeds in very dense colonies on coasts and islands, including Isla Rasa and Montague Island in Mexico, as well as South Bay Salt Works (San Diego) and Bolsa Chica Ecological Reserve in California. Exceptionally, vagrants can occur inland on suitable large freshwater lakes.
The elegant tern feeds by plunge-diving for fish, almost invariably from the sea, like most Thalasseus terns. It usually dives directly, and not from the "stepped-hover" favored by the Arctic tern. The offering of fish by the male to the female is part of the courtship display.
This Pacific species has wandered to western Europe as a rare vagrant on a number of occasions. The first European record was at Carlingford Lough in County Down, Northern Ireland, in late June 1982. It has nested in Spain, and has interbred with a Sandwich tern in France. There is also one record from Cape Town, South Africa, in January 2006, the first record for Africa. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Channel Islands National Park | 🇺🇸 United States | |
| 2 | Cabo Blanco Absolute Nature Reserve | 🇨🇷 Costa Rica | |
| 3 | Las Baulas Marine National Park | 🇨🇷 Costa Rica | |
| 4 | Bahía de Loreto National Park | 🇲🇽 Mexico | |
| 5 | Machalilla National Park | 🇪🇨 Ecuador | |
| 6 | Carara National Park | 🇨🇷 Costa Rica | |
| 7 | Ostional Wildlife Refuge | 🇨🇷 Costa Rica | |
| 8 | Santa Rosa National Park | 🇨🇷 Costa Rica | |
| 9 | El Vizcaíno Biosphere Reserve | 🇲🇽 Mexico | |
| 10 | Palo Verde National Park | 🇨🇷 Costa Rica | |
| 11 | Corcovado National Park | 🇨🇷 Costa Rica | |
| 12 | Marino Ballena National Park | 🇨🇷 Costa Rica | |
| 13 | Redwood National Park | 🇺🇸 United States | |
| 14 | Piedras Blancas National Park | 🇨🇷 Costa Rica | |
| 15 | Galápagos Islands | 🇪🇨 Ecuador |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | San Diego | 🇺🇸 United States | |
| 2 | Tijuana | 🇲🇽 México | |
| 3 | Lima | 🇵🇪 Peru | |
| 4 | San Francisco | 🇺🇸 United States | |
| 5 | Los Angeles | 🇺🇸 United States | |
| 6 | Durban | 🇿🇦 South Africa | |
| 7 | Panama City | 🇵🇦 Panama |
With luck
About 10% of wildlife watchers report an Elegant Tern sighting in San Francisco on a given day, based on 5,554 verified sightings from GBIF citizen-science data. It is the 120th most-seen of the 375 birds we can rate there. Over three days the chance rises to about 20%, and over a week to about 30%, if each day is a fresh chance.
April and July–November
In those months about 10% of wildlife watchers report an Elegant Tern in San Francisco on a given day, against under 5% in May–June and December–March, the lowest months. Those are among San Francisco's driest months, with about 20 mm of rain a month against 110 mm in December.
Between 1 and 4 pm
Across all the parks we cover, that three-hour window holds the most Elegant 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.
Among the best
Of the 7 cities where we can rate Elegant Tern sightings, San Francisco ranks 4th at about 10%, level with the leaders once rounded. The best odds are in San Diego (United States, about 10%), Tijuana (México, about 10%) and Lima (Peru, about 10%).
Same family: Laridae
The closest relatives of the Elegant Tern that you can see in San Francisco (family Laridae, Gulls, Terns, and Skimmers) are California Gull (about 40%), Western Gull (about 30%) and Ring-billed Gull (about 20%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Elegant Tern is recorded against all the birds logged in San Francisco (5,554 verified sightings), 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.
