Hudsonian Whimbrel

Overview

The Hudsonian whimbrel (Numenius hudsonicus) is a large shorebird — crow-sized, with the long decurved bill and bold head stripes that make curlews and whimbrels unmistakable on any beach. It was formally split from the Eurasian whimbrel (N. phaeopus) in 2019 on the basis of genetic and morphological differences, elevating the North American bird to full species status. Adults have brownish upperparts streaked with buff, a pale supercilium bordered by dark lateral crown stripes, and a long bill that curves distinctly downward in the distal third — adapted for extracting crabs and marine worms from soft substrate.

The species is a long-distance migrant, breeding on Arctic tundra and wintering along coastal South America. Migration routes follow both Pacific and Atlantic coasts of North America, with Costa Rica’s Caribbean shore lying on the Atlantic flyway.

Why Tortuguero

The long Tortuguero beach and the river mouth habitats at Barra de Tortuguero and the Colorado delta provide the mudflat and wet-sand foraging habitat whimbrels use on migration. The species is not a Tortuguero speciality — it passes through along the entire Caribbean coast — but the park’s protected beach (no vehicle traffic, limited disturbance) is better quality stopover habitat than most of the Caribbean coastline north and south of the park.

The name Great Esquimaux Curlew used in Audubon’s original plate (Pl. 237, Birds of America) reflected 19th-century usage; the species’ current English name and its separation from the Eurasian bird are both 20th–21st century developments.

How to see one (honestly)

• Visit the Tortuguero beach during August–October or February–April.
• Walk south from the village toward the river mouth at low tide. Look for large brownish shorebirds probing actively in wet sand or standing at the tide line.
• The decurved bill and striped head are the field marks — no other shorebird regularly on this beach combines that bill shape with that size.
• Small flocks (5–25 birds) may aggregate near the river mouth where the beach meets the lagoon outlet. Scan the exposed sandbars there.
• If you miss the migration windows, the species will not be present — it does not winter in Costa Rica.

Status note

The IUCN classifies Numenius hudsonicus as Least Concern following a population recovery from severe 19th-century hunting pressure, when the species was nearly extirpated along its migration corridors. Current populations are regarded as stable or recovering, though North American shorebird monitoring programs flag ongoing habitat degradation in both breeding (Arctic tundra) and wintering grounds. The species remains on High Conservation Concern watchlists in North America.