Wilsons Phalarope (Phalaropus tricolor)

Wilsons Phalarope

[order] CHARADRIIFORMES | [family] Scolopacidae | [latin] Phalaropus tricolor | [UK] Wilsons Phalarope | [FR] Phalarope de Wilson | [DE] Wilson-Wassertreter | [ES] Falaropo Tricolor | [NL] Grote Franjepoot

Subspecies

Monotypic species

Physical charateristics

Wilson’s Phalarope is a slender, small-to-medium sized shorebird with long legs and a long, needlelike bill. Females are more brightly colored than males; in breeding plumage, females have a gray crown, a blackish-burgundy stripe running from the base of the bill down the length of the neck, grayish upperparts with some burgundy markings, and whitish underparts. Males have a dark head, grayish-brown upperparts, a touch of chestnut on the upper breast, and white underparts. During breeding season, both sexes have black legs. In the winter, the sexes look alike, with yellow legs, pale gray upperparts, and white underparts.

Listen to the sound of Wilsons Phalarope

[audio:http://www.aviflevoland.nl/sounddb/W/Wilsons Phalarope.mp3]

Copyright remark: Most sounds derived from xeno-canto

wingspan min.: 38 cm wingspan max.: 41 cm
size min.: 22 cm size max.: 24 cm
incubation min.: 16 days incubation max.: 21 days
fledging min.: 0 days fledging max.: 21 days
broods: 1   eggs min.: 3  
      eggs max.: 4  

Range

North America : Central

Habitat

On its breeding grounds, Wilson’s Phalarope prefers shallow freshwater marshes in prairie and other open country. On migration, the species gathers in huge numbers at salty or alkaline lakes like California’s Mono Lake and Utah’s Great Salt Lake. This bird is also found on salty lakes on its South American wintering grounds.

Reproduction

Compared to other shorebirds, the Wilson’s Phalarope has reversed many typical sexual roles. Females display brighter plumage, court and defend mates, fight off other females, and provide almost no care for eggs or young. During migration and in loose breeding colonies, non-territorial females gather in small groups to court an available male. The females display with exaggerated postures and a “chug” call. After bonding, pairs stay together until the eggs are laid. Females are then free to court other males.

The pair begins construction on a simple nest, which the male completes. During incubation, females defend the nest by pretending to incubate a false “nest.” Males distract intruders by acting injured. Within an hour of hatching, the fully feathered chicks can walk, swim, and feed independently, but require brooding to keep them warm.

To court males, females stretch out their colorful necks, puff out their neck feathers, and make a husky call. Once a female mates with a given male, she leaves a set of eggs with him, and then moves on to attempt to mate with other males. The female might help choose a nest site, but the male completes the construction of a nest, which is a shallow depression on the ground, near water. A typical clutch of four eggs is incubated by a male for 18-27 days. The downy chicks leave the nest within a day of hatching, and find their own food. The male does tend to the young for some time, brooding them when they are very young.

Feeding habits

Like other phalaropes, the Wilson’s often spins on the water, at speeds of up to 60 turns per minute. The purpose of this whirling behavior may be to churn the muddy bottom, excite small aquatic creatures, and condense them in the swirls, where they can be picked off the surface. Wilson’s phalaropes consume flies, beetles, brine shrimp, and other tiny marine creatures.

Conservation

This species has a large range, with an estimated global Extent of Occurrence of 3,800,000 km2. It has a large global population estimated to be 1,500,000 individuals (Wetlands International 2002). Global population trends have not been quantified, but the species is not believed to approach the thresholds for the population decline criterion of the IUCN Red List (i.e. declining more than 30% in ten years or three generations). For these reasons, the species is evaluated as Least Concern.
Wilsons Phalarope status Least Concern

Migration

Transequatorial migrant, wintering in southern South America, though exceptional winter records from Texas and southern California. Differs from other phalaropes in preference for inland aquatic habitats, reflected in distribution on migration and in winter; pelagic observations extremely rare.
Infrequent east of Mississippi valley; rare visitor (mainly autumn) to Canadian maritime provinces and Atlantic states of USA. European records perhaps extreme cases of eastward vagrancy that involved ?overshooting? of western Atlantic coast. However, European records date only from 1954, with increased incidence since 1960s; this coincides with expansion of small population breeding south-east Canada. High proportion of records in spring (notably in Fenno-Scandia) and winter records in Britain and France indicate regular overwintering and north-south migration in Old World now.

Distribution map

Wilsons Phalarope distribution range map

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