The Peruvian booby has brown upperparts, and white underparts, as well as a white head. There is noticeable white mottling on the upper side of the wings. Their wing-coverts are tipped white, creating a scale-like pattern. They have a long, pointed, grey bill. Their feet are webbed and also grey; as opposed to the characteristic coloring of the blue-footed and red-footed boobies. Female boobies tend to be larger than their male counterparts: their bodies an average of 19% heavier, and their wings 4% larger.
The rufous-collared sparrow feeds on the ground on seeds, fallen grain, insects and spiders. It will sometimes join mixed-species feeding flocks and has been observed to pick termites from spider webs. It is usually seen in pairs which hold small territories, or in small flocks. Tame and approachable, it is common throughout its large range and not considered threatened by the IUCN.