Thalasseus sandvicensis
Silhouette: JJ Harrison (vectorized by T. Michael Keesey) · PhyloPic
In 3 days ~10% in a week ~20%
The Sandwich tern (Thalasseus sandvicensis) is a tern in the family Laridae. It is very closely related to the lesser crested tern (T. bengalensis), Chinese crested tern (T. bernsteini), Cabot's tern (T. acuflavidus), and elegant tern (T. elegans) and has been known to interbreed with both elegant and lesser crested terns. It breeds in the Palearctic from Europe to the Caspian Sea, and winters in the Mediterranean and on the coasts of Africa, India, and Sri Lanka.
The Sandwich tern is a medium-large tern with pale silvery-grey upperparts, white underparts, a yellow-tipped black bill, and a shaggy black crest which becomes less extensive in winter with a white crown. Young birds bear grey and blackish scalloped plumage on their backs and wings. It is a vocal bird. It nests in a ground scrape and lays one to three eggs.
Like all Thalasseus terns, the Sandwich tern feeds by plunge-diving for fish, usually in marine environments, and the offering of fish by the male to the female is part of the courtship display. The terns are small to medium-sized seabirds, gull-like in appearance, but usually with a more delicate, lighter build and shorter, weaker legs. They have long,... Wikipedia →
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Dakar | 🇸🇳 Senegal | |
| 2 | Algiers | 🇩🇿 Algeria | |
| 3 | Rabat | 🇲🇦 Morocco | |
| 4 | Havana | 🇨🇺 Cuba | |
| 5 | Vitória | 🇧🇷 Brazil | |
| 6 | Kuwait City | 🇰🇼 Kuwait | |
| 7 | Casablanca | 🇲🇦 Morocco | |
| 8 | Liverpool | 🇬🇧 United Kingdom | |
| 9 | Porto | 🇵🇹 Portugal | |
| 10 | Dublin | 🇮🇪 Ireland |
Rare
Under 5% of wildlife watchers report a Sandwich Tern sighting in Maputo on a given day, based on 10 verified sightings from GBIF citizen-science data. It is the 93rd most-seen of the 115 birds we can rate there. Over three days the chance rises to about 10%, and over a week to about 20%, if each day is a fresh chance.
April
In that month about 10% of wildlife watchers report a Sandwich Tern in Maputo on a given day, against under 5% in May to March, the lowest months.
Between 9 am and noon
Across all the parks we cover, that three-hour window holds the most Sandwich 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.
30th of 50
Of the 50 cities where we can rate Sandwich Tern sightings, Maputo ranks 30th at under 5%. The best odds are in Dakar (Senegal, about 50%), Algiers (Algeria, about 20%) and Rabat (Morocco, about 20%).
GBIF citizen-science records
It is estimated from how often the Sandwich Tern is recorded against all the birds logged in Maputo (10 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.
