The near-threatened Serra Finch (Embernagra longicauda) is restricted to the main mountain ranges in eastern Brazil inhabiting campos rupestres (rocky fields). We mapped 17 mated pairs in a 138-ha area within Serra do Cipó National Park; a density of 0.25 adults/ha. Estimated average territory size varied from 2.52 ± 0.77 ha (95% kernel) to 3.35 ± 0.90 ha (100% minimum convex polygon). The distance between territory centers of neighboring pairs was 162.38 ± 28.93 m. The overlap between neighboring territories was 15.3 ± 5.9% (95% kernel) and 2.0 ± 2.3% (polygon method). Pairs remained together throughout the year in the same territories and defended these against intruding neighbors. Analyses of habitat selection indicated preference for woodland and scrubland habitats associated with humid valleys, while grasslands were avoided. The Serra Finch used the available habitats more than expected from random at different spatial scales. Our data identified habitats that should be priority for conservation of the Serra Finch.