It nests in shallow marshes primarily in the interior West and Great Lakes regions. One of few birds to undergo a post-breeding, molt migration, Wilson's Phalaropes then travel to several traditional sites. Only then, armed with new feathers and a full tank of fuel, will they attempt their nonstop, 54- hour flight to central South America. Most will spend the winter in the saline lakes of the central Andean highlands, and smaller numbers will reach the lowland lakes and marshes of the Pampas and Patagonia of Uruguay and Argentina, as well as coastal Ecuador, Peru and Chile. Phalaropes are among a handful of bird species that reverse the role of the sexes.
Females are larger and more brightly colored than males.
They often mate with more than one male, have more than one nest and, after egg-laying, they leave their families to the sole care of the males. Females even gather in flocks to aggressively compete for each single male. Although phalaropes are highly gregarious, females are territorial during the breeding period and defend their mates against other females. Interestingly, recent research indicates that for many species of birds some offspring are fathered by neighboring males and not by the female's mate. However, a new study has found that in 17 Wilson's Phalarope families, all of the young were fathered by the male that raised them.