The Rusty-margined Guan lives in South American forests and scrub. In the Paraná forest of Argentina, pale feather edges make the adult breast look scaled.
Adults described from Argentina's Paraná forest have a grey-brown breast edged with pale grey, creating a scaled effect. Fresh wing feathers have rufous margins.
Rusty-margined Guans eat fruit in South American forests, including native remnants within modified landscapes. Seeds may be transported in their droppings.
A 1999–2000 study recorded fruits from fifty-two plant species. Later captive experiments found germination after gut passage, with different outcomes among plant species.
A 2024 camera-trap study in three landscapes found lower ground-use frequency where intensively managed forests were more prevalent. Native-forest conservation and habitat research support this seed-dispersing bird.
An extinction-risk assessment has not been added yet.
Maintaining native vegetation within agricultural and plantation landscapes supports food resources and movement habitat. Ground-use patterns vary with surrounding land cover.