Diademed Sandpiper-Plover

The Diademed Sandpiper-Plover, or Diademed Plover, is a distinctive bird with a length of 16.5 to 19 cm and a weight ranging from 28 to 46 grams. Both sexes share a similar appearance, characterized by a black bill with a slight downward curve and vibrant orange legs and feet. The adult's facial features include a black face with a prominent white supercilium that wraps around the back of the head. Its crown is black, transitioning to a bright rufous nape, while the upperparts are a dark brownish-gray. The rump and uppertail coverts are black, and the tail is black with white-tipped feathers. The bird's throat is white, and the chest, belly, and flanks exhibit black and white barring, with the vent and undertail coverts being pure white. Juveniles present a more subdued coloration, with brownish-gray upperparts speckled with cinnamon, a grayish supercilium, and a nape tinged with cinnamon or rufous.

Identification Tips

When identifying the Diademed Sandpiper-Plover, look for its striking facial pattern, the white supercilium, and the contrasting black and rufous on the head. The barred underparts and the white vent area are also key features. The bird's small size, black bill, and orange legs are additional distinguishing characteristics.

Habitat

This species is a habitat specialist, predominantly found in peatlands and bogs within the Andean region. These areas are marked by grassy banks interspersed with streams and seasonal pools, providing the moist environment the bird prefers.

Distribution

The Diademed Sandpiper-Plover inhabits the Andes, with its range extending from central Peru through western Bolivia to central Chile and south-central Argentina. Its altitudinal range varies from 4,100 to 5,000 meters in Peru, descending to as low as 2,000 meters in the southern parts of its distribution.

Behaviour

Typically observed alone or in pairs, the Diademed Sandpiper-Plover's social structure is not fully understood. It could be attributed to social monogamy, territorial behavior, sparse population, or simply a lack of comprehensive study.

Song & Calls

The bird's vocalizations include a clipped "pic" or "pic-pic" call while foraging or in flight. Alarm calls are described as a plaintive, slightly drawn-out "wheehu," a sharper "whee-u!," and a surprisingly loud screamed whistle, "whEEHU!"

Breeding

Breeding occurs from October to December in Chile and may extend into January in Bolivia. The nest is a simple ground hollow or a platform of dried grass, typically containing two eggs. Incubation periods and fledging times remain undocumented.

Diet and Feeding

The Diademed Sandpiper-Plover forages alone or with a partner, probing wet ground or shallow water and picking prey from the water's surface and aquatic vegetation. Its diet primarily consists of aquatic invertebrates.

Conservation status

The IUCN has classified the Diademed Sandpiper-Plover as Near Threatened. With an estimated population of 1,500 to 7,000 mature individuals, the species is believed to be in decline. Threats include water resource demands, overgrazing, road networks, human disturbance, and the projected severe reduction of the high Andes peatlands ecosystem due to climate change, with up to 75% loss anticipated by 2100.