Wilson's Phalarope

How to find it

Start with the Gulf of Nicoya and check its salt pans first. Then try coastal lagoons, freshwater ponds and marshes. Scan the open water rather than only the mud edges, because this bird feeds mainly while swimming. Look for small pale birds turning in circles. Since it usually gathers in groups, finding one often means finding several. When a bird flies, check for the white rump and plain wings.

How to recognise it

The birds seen in Costa Rica are in non-breeding plumage, and in that plumage both sexes look alike.

Look for these marks:

- pale gray above and white below

- poorly defined face markings, with no black eye patch

- about 23 cm long, slightly larger than the Red Phalarope

- the largest and most land-loving of the three phalarope species

The best mark comes in flight. In every plumage a flying Wilson's Phalarope shows a white rump and plain wings with no white wing stripe. That separates it from the Red-necked and Red Phalaropes, which are slightly smaller and show a black eye patch in non-breeding plumage.

Behaviour and diet

Feeding is the signature of the species. It swims in tight spinning circles to bring small invertebrates to the surface, then picks them off. It also lunges at flies and probes soft mud.

In Costa Rica it usually gathers in groups, picking aquatic insects and small crustaceans from the water or mud surface. Birders at Gulf of Nicoya salt ponds say the birds behave like tiny ducks on the water.

Where it lives

On migration and in winter this phalarope prefers salty lakes rich in invertebrate prey. In Costa Rica the places to check are salt pans, coastal lagoons, freshwater ponds and marshes, with the Gulf of Nicoya the best area.

A Costa Rican natural history page maps its range in the Pacific Central, Arenal, Guanacaste, Osa and Tempisque conservation areas, and Isla del Coco, with scattered reports from other Pacific lowland sites. There are no reports from the Caribbean side.

When to see it

It passes through as a migrant in September and October, and again in spring. A few birds may stay the winter on the salt pans around the Gulf of Nicoya, at least in some years, and non-breeding birds are sometimes seen in summer.

Similar birds

In non-breeding plumage it can be mistaken for a Stilt Sandpiper or a Lesser Yellowlegs, both of which are less pale gray. The phalarope feeds more actively, while the yellowlegs is slower and more methodical. Against the Red and Red-necked Phalaropes, look for the lack of a black eye patch and for the clear white rump.

Names and lore in Costa Rica

Costa Rican Spanish uses Falaropo Tricolor, also written Falaropo de Wilson. Elsewhere in the Spanish-speaking world it is called Pollito de mar tricolor (Chile) and Falaropo pico largo (Honduras).

Status and conservation

The AOCR list marks it as a migrant (M), and the IUCN rates the species Least Concern.

Photography tips

Check the ponds at high tide for closer views. At low tide birds scatter over huge mud flats and become distant silhouettes. Once the flats flood they crowd into accessible ponds.