Courtesy Kenn Kaufman
Wilson's Phalaropes breed across the Great Plains of North America, and appear to be expanding their range south and east. The wintering range stretches from Peru to the tip of South America, with dense populations in Peru, Chile, Bolivia, and northwest Argentina.
A legend for the range map to the right can be found here
The Wilson's Phalarope breeds in the wetlands of North America's Great Plains and northern Rocky Mountains, favoring shallow water with adjacent mudflats and wet grasses. In migration and during winter, this shorebird prefers the shallows of salt lakes and ponds.
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.
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. The female lays four buff-colored eggs, marked with brown. Under the male's care, they hatch in 18 to 27 days. 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. Researchers have not yet observed the juvenile stages of Wilson's Phalaropes.
From the breeding grounds, Wilson's Phalaropes migrate in segregated groups: females depart first, followed by males, and finally, juveniles. All three groups stage at North American salt lakes before their non-stop flight to southern South America. Spring migration progresses through the mountains of South, Central, and North America to Cheyenne Bottoms, Kansas, where nearly all Wilson's Phalaropes stage.