This canastero is concentrated in the humid Pampas and has black streaking on its back. A research review describes partial seasonal movement; Brazilian records include tall grass and sedges on a coastal plain.
A Brazilian field account describes a bulky bird with a forked-looking tail, sandy-gray upperparts boldly streaked black, a whitish chin, and buff underparts.
Reported habitat is tall grass and sedges near marshes or seasonally flooded ground. A 2022 review of records describes the species as a partial seasonal migrant.
An extinction-risk assessment has not been added yet.