
Heteronetta atricapilla (MPR):occurs from Chile and Argentina to southern Brazil, Paraguay and Bolivia (Sick, 1997). Populations that breed further south of the distribution fly north during winter (Carboneras, 1992a). Calabuig et al. (2010) suggest that this species presents the same pattern as Coscoroba coscoroba, in which part of the population migrates and the rest remain in one area throughout the year. Individuals that were banded in Santiago del Estero in June and then recovered in RS in August (Olrog, 1974) proved migration between Argentina and Brazil (RS).This species breeds in RS between October and December (Maurício et al., 2013).
