Volcano Junco is the southernmost member of the juncos, a group of sparrows that occurs only in North America. Unlike other species in the genus, the tail of Volcano Junco is almost entirely dark (lacking white outer rectrices, which are characteristic of other species of junco), and its upperparts are streaked black and brown, rather than being uniform gray, brown, or rufous. Volcano Junco occurs at highland sites, many of which are volcanoes, in Costa Rica and also westernmost Panama; since its preferred highland habitat is restricted to mountain tops, this species has a rather fragmented distribution. Where it occurs, however, it can be relatively common. Volcano Junco has a bright yellow iris and a pink bill; the head and underparts are mostly pale gray, and it has a conspicuous black mask. Volcano Junco is rather easy to find and to observe, but even so, its natural history is very poorly known.