Thalasseus albididorsalis
Silhouette: JJ Harrison (vectorized by T. Michael Keesey) · PhyloPic
In 3 days ~20% in a week ~40%
The West African crested tern (Thalasseus albididorsalis) is a bird species in the family Laridae. Until 2020 it was considered a subspecies of the New World royal tern, Thalasseus maximus. The West African crested tern was long thought to be a subspecies of royal tern. A study published in 2005 showed that it is more closely related to the lesser crested tern (Thalasseus bengalensis), and a 2017 publication confirmed and expanded on those results.
The West African crested tern is one of the three larger crested terns, along with royal tern and greater crested tern. Its tail is shallowly forked and the adult's bill is long and orange. It is about 50 cm (20 in) long, with a wingspan between 125–135 cm (49–53 in), and weighs 320–440 g (11–16 oz) with a mean weight of 367 g (12.9 oz). In breeding plumage its underside is white and upper parts silvery grey; the top of the head is black with a shaggy crest at the rear. As in all Thalasseus terns, the... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|
More parks will be added in future updates.
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Dakar | 🇸🇳 Senegal | |
| 2 | Luanda | 🇦🇴 Angola | |
| 3 | Freetown | 🇸🇱 Sierra Leone | |
| 4 | Serrekunda | 🇬🇲 Gambia | |
| 5 | Accra | 🇬🇭 Ghana |
With luck
About 10% of wildlife watchers report a West African Crested Tern sighting in Freetown on a given day, based on 6 verified sightings from GBIF citizen-science data. It is the 54th most-seen of the 79 birds we can rate there. Over three days the chance rises to about 20%, and over a week to about 40%, if each day is a fresh chance.
December and January
In those months about 10% of wildlife watchers report a West African Crested Tern in Freetown on a given day, against under 5% in February, May–June and September, the lowest months. Those are among Freetown's driest months, with almost no rain against 700 mm in August. March–April, July–August and October–November have too few records to rate.
Between 1 and 4 pm
Across all the parks we cover, that three-hour window holds the most West African Crested 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.
3rd of 5
Of the 5 cities where we can rate West African Crested Tern sightings, Freetown ranks 3rd at about 10%. The best odds are in Dakar (Senegal, about 40%) and Luanda (Angola, about 10%).
GBIF citizen-science records
It is estimated from how often the West African Crested Tern is recorded against all the birds logged in Freetown (6 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.
