Costa Rican Brushfinch is the northernmost representative of a group of large sparrows, ranging from southern Central America south to northern Argentina, that formerly were considered to represent a single species ("Stripe-headed Brushfinch", Arremon torquatus). "Stripe-headed Brushfinch" now is classified as no fewer than eight (!) species, most of which have restricted geographic distributions in Central America and northern South America. Costa Rican Brushfinch fits this pattern, as it is restricted to the humid mountains of Costa Rica and western Panama. All members of the "Stripe-headed Brushfinch" complex are similar, with olive upperparts, a white throat, and extensive black on the head, usually offset with a broad pale supercilium; in the case of Costa Rican Brushfinch, the supercilium is pale gray. The natural history of Costa Rican Brushfinch is very poorly known. Generally, however, its behavior is similar to that of related species: Costa Rican Brushfinches are solitary or in pairs, and, while generally fairly common, they easily are overlooked as they forage quietly on the ground or in the undergrowth of humid forest and dense second growth.