A bright flycatcher found in marshes in the Andes from Colombia to Argentina. Yellow below and olive above, sometimes showing a hint of a dark mask and dull yellowish edges on the wing feathers. Distinctive in habitat, although could be confused with a female Masked Yellowthroat, which has a pinkish bill and legs. Forages singly or in pairs; can be difficult to see in dense marsh grasses. Mostly occurs from 1,000 to 3,500 m, but some appear to move into lowlands in the winter in southern part of range. Gives single nasal calls as well as a whirring noise produced by the wings.