Hydroprogne caspia
Silhouette: Andy Wilson · PhyloPic
In 3 days ~10%
The Caspian tern (Hydroprogne caspia) is the world's largest species of tern, with a subcosmopolitan but scattered distribution. Despite its extensive range, it is monotypic of its genus, and has no accepted subspecies. The genus name is from Ancient Greek hudro-, "water-", and Latin progne, "swallow". The specific caspia is from Latin and, like the English name, refers to the Caspian Sea.
It is the world's largest tern with a length of 48–60 cm (19–24 in), a wingspan of 127–145 cm (50–57 in) and a weight of 530–782 g (18.7–27.6 oz). Adult birds have black legs, and a long thick red-orange bill with a small black tip. They have a white head with a black cap and white neck, belly, and tail. The upper wings and back are pale grey; the underwings are pale with dark primary feathers. In-flight, the tail is less forked than other terns, and wingtips are black on the underside. In winter, the black cap is still present (unlike many other terns), but with some white streaking on the forehead. The call is a loud heron-like croak.
Their breeding habitat is large lakes and ocean coasts in North America (including the Great Lakes), and locally in... Wikipedia →
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Dakar | 🇸🇳 Senegal | |
| 2 | Kuwait City | 🇰🇼 Kuwait | |
| 3 | Karachi | 🇵🇰 Pakistan | |
| 4 | Helsinki | 🇫🇮 Finland | |
| 5 | Auckland | 🇳🇿 New Zealand | |
| 6 | Chicago | 🇺🇸 United States | |
| 7 | Serrekunda | 🇬🇲 Gambia | |
| 8 | Jeddah | 🇸🇦 Saudi Arabia | |
| 9 | Los Angeles | 🇺🇸 United States | |
| 10 | San Diego | 🇺🇸 United States |
| # | Zoo / Centre | Country | |
|---|---|---|---|
| 1 | Oklahoma City Zoo and Botanical Garden | 🇺🇸 United States | |
| 2 | Tracy Aviary | 🇺🇸 United States | |
| 3 | South Carolina Aquarium | 🇺🇸 United States |
Rare
Under 5% of wildlife watchers report a Caspian Tern sighting in Great Otway National Park on a given day, based on 63 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 122nd most-seen of the 175 birds we can rate there. Over three days the chance rises to about 10%, if each day is a fresh chance.
August
In that month about 10% of wildlife watchers report a Caspian Tern in Great Otway National Park on a given day, against under 5% in September to July, the lowest months.
Between 9 am and noon
Across all the parks we cover, that three-hour window holds the most Caspian 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.
39th of 65
Of the 65 parks where we can rate Caspian Tern sightings, Great Otway National Park ranks 39th at under 5%. The best odds are in Rottnest Island (Australia, about 70%), Padre Island National Seashore (United States, about 50%) and West Coast National Park (South Africa, about 40%). All parks ranked.
Same family: Laridae
The closest relatives of the Caspian Tern that you can see in Great Otway National Park (family Laridae, Gulls, Terns, and Skimmers) are Silver Gull (about 30%), Crested Tern (about 10%) and Pacific Gull (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Caspian Tern is recorded against all the birds logged in Great Otway National Park (63 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.
