Large-billed Tern

How to find it

Treat any sighting as a lucky surprise, not a target. The only places named in the Costa Rican records are the Río Tortuguero and Matina, both in Limón province on the Caribbean side. Birders hoping for a vagrant could check large rivers and lagoons there. Scan terns resting on sandbars and river beaches, since the species often keeps company with other terns and skimmers. Check the bill first: thick and entirely yellow is the clue. Watch too for a bird that dives for fish or chases others to steal their food.

How to recognise it

Start with the bill: thick, long, pointed and entirely yellow, and it looks too big for the head. Then add the rest of the pattern.

Black crown and a short tail.

In flight, three wing tones: black outer wing, pale middle and gray inner wing, with a gray tail.

A striking flight pattern of black outer feathers and a white triangle on the inner wing, which recalls a Sabine's Gull.

Outside the breeding season, adults have a paler forehead and crown, with the black limited to a patch from behind the eye to the nape.

Young birds have a browner crown and wings.

These descriptions are for the species in general, not for Costa Rica.

What it sounds like

Recording: Eduardo Luis Beltrocco, CC BY 4.0, source, read 4 Nov 2026.

Behaviour and diet

Across its range it is often alone or in pairs, but it may roost in small flocks. Its flight is strong and direct. It eats fish and aquatic invertebrates, plunging into the water to catch them, and it also takes insects in flight. It can be aggressive and steal food from other birds.

It nests in colonies on sandbars and river beaches, often alongside other terns and skimmers. No nest is built, and the eggs lie hidden in grass or reeds. It breeds mostly inland on sandy river bars. This describes the species in general, not something recorded in Costa Rica.

Where it lives

Across its range it lives along large rivers and lakes, and seasonally on the coast. Outside the breeding season it may be found near estuaries and coastlines.

Its normal range is most of South America east of the Andes and north of the Pampas. It has turned up as a vagrant in Panama, the nearest country to Costa Rica in that list. In Costa Rica the records come from the Caribbean lowlands of Limón province.

When to see it

One Costa Rican record dates to 15 March 2003 at the Río Tortuguero. A single date is far too little to show any pattern.

Similar birds

The Yellow-billed Tern is very similar and shares its range. It is also listed as accidental (A) in Costa Rica. The Gull-billed Tern is a stocky tern with a thick black bill, and it often snatches insects in the air instead of diving for fish. Check the bill colour to tell them apart: entirely yellow for this tern, black for the Gull-billed.

Names and lore in Costa Rica

The official AOCR name is Charrán Picudo (Charrán de Río). Spanish sources also call it Atí, Gaviotín Atí, Charrán Picogrueso, Gaviotín de Pico Grande and Gaviotín Picudo. These are general Spanish names, not specific to Costa Rica.

Status and conservation

The official Costa Rican list (AOCR, updated June 2026) gives it status A, and Avibase marks it rare or accidental, so it is a vagrant here and not a resident.