Sargasso Shearwater

How to find it

Go out on a boat trip, often called a pelagic, in the Caribbean Sea off Costa Rica. A late December trip found Audubon's Shearwaters, along with a rare Manx Shearwater. Because the species feeds in inshore as well as offshore waters, a boat close to the coast may still find it. Check the undertail on every small black-and-white shearwater as it passes. Keep the Manx in mind, and the other small black-and-white species on the Costa Rican list.

How to recognise it

This is a small tropical seabird and a small shearwater. It is about 26 to 30 cm long and weighs around 200 g, with a wingspan of about 69 cm. Males and females look alike, so there is no need to sort the sexes.

Look for these marks:

Blackish-brown upperparts.

White underparts.

White face below the eye.

Blackish undertail.

The dark undertail coverts are the detail to check. They separate it from its closest lookalike, the Manx Shearwater, which has white undertail coverts.

Behaviour and diet

It eats fish, squid and crustaceans. It may be seen alone or in large groups, so a single bird passing and a gathering over the water are both possible.

It is adaptable about where it feeds. It can be found far out at sea, in offshore waters and in inshore waters, so a boat close to the coast may still find it. Birds take about 8 years to reach breeding age.

Where it lives

This is an ocean bird. Range-wide it nests mainly in the Caribbean and ranges widely across the western Atlantic when not breeding.

Across the Caribbean it is often the most numerous tubenose seabird along the eastern edge of the West Indies. It breeds on a few islets off Nicaragua and Panama, which are close to Costa Rica's Caribbean waters. In Costa Rica the place to look is the Caribbean Sea off the coast, not the land.

When to see it

One Caribbean boat trip that found Audubon's Shearwaters went out in late December. Range-wide, birds breed from January to July at Caribbean colonies and otherwise stay year-round in Caribbean and nearby Atlantic waters.

Similar birds

Manx Shearwater is easily confused with this bird. The Manx has white undertail coverts and a longer bill when the two are compared side by side, while Sargasso shows dark undertail coverts. Costa Rica's official list also has Galapagos Shearwater (Pardela de las Galápagos), another small black-and-white shearwater to rule out at sea.

Names and lore in Costa Rica

Costa Rica's list uses Pardela de Audubon. Other Spanish names for the species are Pampero de Audubon and Pardela Garrapatera, though neither is known as a Costa Rican nickname.

Status and conservation

The 2025-2026 official Costa Rican list, updated June 2026, keeps it as Sargasso Shearwater with status M, meaning migrant, beside Galapagos and Manx Shearwaters, also listed as M.

Photography tips

On one boat trip off Costa Rica, two Audubon's Shearwaters flew so close that binoculars were not needed, and the writer photographed them with a hand-held camera. That trip was on the Pacific side, so the birds may be a related species.