Head to head
Royal Tern vs Caspian Tern
The royal tern and Caspian tern are the two largest members of the entire tern family, similar enough in size to be confused at a distance.
| Royal Tern | Caspian Tern | |
|---|---|---|
| Scientific name | Thalasseus maximus | Hydroprogne caspia |
| Relative size | Second-largest tern | Largest tern in the world |
| Bill colour | Bright orange | Blood-red |
| Call | Typical tern calls | Harsh, crow-like |
| Native range | Americas, West Africa | Near-global, multiple continents |
| Conservation status | Least Concern | Least Concern |
| Population trend | Stable | Stable |
| Habitat | Coastal | Coastal, wetlands |
Royal Tern vs Caspian Tern: common questions
Which is bigger, the royal tern or the Caspian tern?
The Caspian tern is bigger, holding the title of largest tern in the world, while the royal tern comes in as the second-largest, close enough in size that the two can be confused at a distance without a clear view of the bill.
How can you tell a royal tern from a Caspian tern?
The most reliable way is bill colour and thickness: the royal tern has a bright orange bill, while the Caspian tern has an even more massive, thick bill in a deeper blood-red colour, along with a distinctly harsher, crow-like call.
Do the royal tern and Caspian tern share the same range?
They overlap in parts of the Americas, but the Caspian tern has a far wider, near-global distribution spanning multiple continents, while the royal tern is more restricted to the Americas and West Africa.