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Summary

The chestnut-capped brushfinch (Arremon brunneinucha) is a species of bird in the family Passerellidae, the New World sparrows. It is found from Mexico to Peru.

Taxonomy and systematics

The chestnut-capped brushfinch was formally described in 1839 with the binomial Embernagra brunnei-nucha. It eventually was reassigned to genus Buarremon and the specific epithet revised to brunneinuchus. Genus Buarremon was still later merged into genus Atlapetes but further study resulted in Buarremon's being resurrected. In 2000 taxonomists again revised the specific epithet to its current brunneinucha. In 2008 taxonomists began merging Buarremon into Arremon.

The chestnut-capped brushfinch's further taxonomy is unsettled. The IOC, AviList, and BirdLife International's Handbook of the Birds of the World assign it these nine subspecies:

A. b. apertus (Wetmore, 1942) A. b. brunneinucha (Lafresnaye, 1839) A. b. alleni (Parkes, 1954) A. b. suttoni (Parkes, 1954) A. b. macrourus (Parkes, 1954) A. b. elsae (Parkes, 1954) A. b. frontalis Tschudi, 1844 A. b. allinornatus (Phelps, WH & Phelps, WH Jr, 1949) A. b. inornatus (Sclater, PL & Salvin, 1879)

However, as of late 2025 the Clements taxonomy assigns a tenth subspecies, A. b. nigralatera (Rowley, 1968), that the others include in A. b. suttoni. Clements also sets A. b. apertus apart within the species, calling it the "chestnut-capped brushfinch (plain-breasted)". Clements groups the others as the "chestnut-capped brushfinch (chestnut-capped)".

This article follows the nine-subspecies model.

Description

The chestnut-capped brushfinch is 16 to 19.5 cm (6.3 to 7.7 in) long and weighs about 32 to 47 g (1.1 to 1.7 oz). It is one of the larger brushfinches. The sexes have the same plumage. Adults of the nominate subspecies A. b. brunneinucha have a wide black mask from their forehead and forecrown down to below the gape and back to the side of the neck. Within it they have a small white spot above the lores....