trinta-réis-de-bico-preto vs trinta-réis-negro

The Gull-billed Tern and Black Tern can be distinguished primarily by their bill and plumage. The Gull-billed Tern has a stout, all-black bill and a more robust body, while the Black Tern is smaller with a more delicate structure and different plumage patterns.

Look for the stout, all-black bill of the Gull-billed Tern, which contrasts with the more delicate structure of the Black Tern. Observe the flight pattern: Gull-billed Terns have a slower, more buoyant flight, while Black Terns have a more erratic, swallow-like flight.

The Gull-billed Tern is generally larger and more robust compared to the smaller, more delicate Black Tern.

Gull-billed Tern has pale gray upperparts with a white body and a black cap in alternate plumage. In contrast, the Black Tern is known for its darker, more variable plumage, often with a black head and body during breeding season.

The Gull-billed Tern has a slower, more buoyant flight, while the Black Tern exhibits a light, buoyant, and erratic flight reminiscent of a butterfly or swallow.

Gull-billed Terns are often found in coastal areas, while Black Terns prefer freshwater habitats.