Caspian Tern vs River Tern

The Caspian Tern is the largest tern with a robust build and a thick red bill, while the River Tern is smaller, more slender, with a yellow bill. Both species are part of the Laridae family but differ significantly in size and bill color.

Bill color is a key differentiator: Caspian Terns have a thick red bill, while River Terns have a yellow bill. Size and structure: Caspian Terns are larger with broader wings. Flight style: Caspian Terns have slow, powerful wing beats; River Terns are more agile. Habitat preference: Caspian Terns are often near coasts, River Terns near freshwater.

The Caspian Tern is notably larger and more robust than the River Tern, which is more slender and smaller.

Caspian Terns have a distinctive black cap and a pale gray body with white underparts. River Terns also have a black cap but are generally paler with a more streamlined appearance.

Caspian Terns are powerful fliers with slow wing beats, often seen plunge-diving for fish. River Terns are also adept at fishing but are more agile and swift in flight.

Caspian Terns are found along coastlines and large inland water bodies, while River Terns prefer freshwater rivers and lakes.

Caspian Terns have a loud, raucous call, often heard in colonies. River Terns have a more melodious and softer call.