The Red Phalarope is the most pelagic of the 3 phalarope species, spending up to 11 months each year in marine habitats. Its migratory routes and winter areas are entirely pelagic, in contrast to those of Red-necked (Phalaropus lobatus) and Wilson's (P. wilsonii) phalaropes, and it generally feeds on smaller invertebrate prey items than the former. Migrants in Alaska feed on crustaceans in mud plumes created by benthic-foraging gray whales (Eschrichtius robustus), or near bowhead whales (Balaena mysticetus), a habit that prompted European whalers to label Red Phalaropes “bowhead birds” (Nelson 1883) and to use flocks to locate whales.
Like other phalaropes, Red Phalaropes show reversed sexual dimorphism, with females larger and more brightly plumaged than males. The species breeds widely across the Holarctic, overlapping in the southern part of its range with the Red-necked Phalarope, but not with Wilson's. When breeding, it is most common in coastal tundra and is seldom found far inland. Where they overlap, Red and Red-necked phalaropes sometimes feed in the same macrohabitats, although Red Phalaropes often use wading-depth water, while Red-necked Phalaropes feed in swimming-depth water.
Like its congeners, the Red Phalarope is nonterritorial, although disputes are common among females seeking access to mates, especially late in the breeding season. The male provides all parental care, including incubation and brood-rearing of precocial young. As expected from the sex-role reversal in this species, some females are polyandrous, especially those nesting early.
In general, less is known about the Red Phalarope than other phalaropes because its breeding and wintering areas are more remote. The paucity of long-term studies on the breeding grounds and scant data from migratory and wintering areas make it impossible to disentangle shifting habitat use from long-term population changes. As in the Red-necked Phalarope, some data indicate that El Niño-Southern Oscillation events may be an important influence on population size. There is some indication of population decreases worldwide, especially in the southern part of the range.
Important information on phenology, nesting, productivity, polyandry, paternity, and site fidelity of breeding Red Phalaropes is available from studies in Canada (Mayfield Mayfield 1978, Mayfield 1979; Dale et al. 1999c) and Alaska (Schamel and Tracy Schamel and Tracy 1977, Schamel and Tracy 1987, Schamel and Tracy 1991). Winter range is delineated for Atlantic (Brown 1980d) and Pacific Oceans (DeGraaf and Rappole 1995), and is most often associated with upwellings. Fall staging is described well for northern Alaskan coastal waters (Connors et al. 1979, Johnson and Herter 1989). Southbound migration is summarized for Alaska (Gabrielson and Lincoln 1959) and California (DeSante and Ainley 1980, Briggs et al. 1984). There are no published quantitative food data for breeding Red Phalaropes in North America; the closest study is from Siberia (Kistchinski and Chernov 1973). There are few quantitative studies of food habits at sea, at least with adequate sample size: northern Alaska littoral zone (Johnson Johnson 1978c, Johnson 1979e; Connors 1984), northern Alaska Beaufort Sea (Divoky 1984b), Bay of Fundy (Canada; Brown and Gaskin 1988), and offshore from California (Briggs et al. 1984).