The grey-browed brushfinch (Arremon assimilis) is a species of bird in the family Passerellidae, the New World sparrows. It is found in Colombia, Ecuador, Peru and Venezuela.

Taxonomy and systematics

The grey-browed brushfinch has a complicated taxonomic history. It was formally described in 1840 with the binomial Tanagra (Arrémon, Vieillot; Embernagra, Lesson) assimilis. It was later reassigned to the genus Buarremon that was later merged into genus Atlapetes. Further study resulted in Buarremons being resurrected.Cadena, C. D., J. Klicka and R. E. Ricklefs. (2007). "Evolutionary differentiation in the Neotropical montane region: molecular phylogenetics and phylogeography of Buarremon brush-finches (Aves, Emberizidae)." Molecular Phylogenetics and Evolution. 44(3): 993-1016. Buarremon assimilis was later reassigned as one of many subspecies of what was then the "stripe-headed brushfinch" (Buarremon torquatus). In 2008 taxonomists began merging Buarremon into Arremon.Richard C. Banks, R. Terry Chesser, Carla Cicero, Jon L. Dunn, Andrew W. Kratter, Irby J. Lovette, Pamela C. Rasmussen, J. V. Remsen, Jr., James D. Rising, Douglas F. Stotz, and Kevin Winker. "Forty-ninth supplement to the American Ornithological Society s Check-list of North American Birds". The Auk 2008, vol. 125:758-768 retrieved January 27, 2023 Following a study published in 2010 and some earlier studies, taxonomists began splitting the "stripe-headed brushfinch" into eight species, one of which was the grey-browed brushfinch.Cadena, C. D., and A. M. Cuervo (2010). "Molecules, ecology, morphology, and songs in concert: how many species is Arremon torquatus (Aves: Emberizidae)?" Biological Journal of the Linnean Society 99(1): 152-176 The proposal passed in June 2011.

The grey-browed brushfinch has these four subspecies:

A. a. larensis (Phelps, WH & Phelps, WH Jr, 1949) A. a. assimilis (Boissonneau, 1840) A. a. nigrifrons (Chapman, 1923) A. a. poliophrys (Berlepsch & Stolzmann, 1896)

A 2014 publication suggested that A. a. larensis might be a full species.López-O., J. P., J. E. Avendaño, N. Gutiérrez-Pinto, and A. M. Cuervo (2014). "The birds of the Serranía de Perijá: the northernmost avifauna of the Andes". Ornitología Colombiana 14:62–93.

Description

The grey-browed brushfinch is long. The sexes have the same plumage. Adults of the nominate subspecies A. a. assimilis have a black crown with a gray stripe in the middle and a gray supercilium that extends to the nape and wraps down around the back of the ear coverts to the sides of the breast. The rest of their face is black. Their upperparts, wings, and tail are olive-green. Their throat is white that continues through the breast and belly. The sides of their breast and flanks are gray and their vent grayish olive. Juveniles are generally olive with dusky cheeks.Jaramillo, A. (2020). Gray-browed Brushfinch (Arremon assimilis), version 1.0. In Birds of the World (J. del Hoyo, A. Elliott, J. Sargatal, D. A. Christie, and E. de Juana, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.sthbrf8.01 retrieved May 6, 2026

Subspecies A. a. larensis has a wider gray supercilium than the nominate and a black band separating the throat and breast. A. a. nigrifrons gray crown stripe begins farther back than the nominate's and its supercilium ends just past the eye. A. a. poliophrys has a black band between the throat and breast. All subspecies have a deep chestnut-brown iris, a black bill, and pinkish to gray legs and feet.

Distribution and habitat

The grey-browed brushfinch has a disjunct distribution along the Andes from Venezuela to Peru. The subspecies are found thus:

A. a. larensis: western Venezuela from northern Táchira north to southeastern Lara A. a. assimilis: from Mérida in western Venezuela south through all three ranges of the Colombian Andes and the Andes of Ecuador into northern Peru's Department of La Libertad A. a. nigrifrons: from southwestern Ecuador's El Oro and Loja provinces south in Peru to La Libertad A. a. poliophrys: Andes of central and southern Peru from the Department of Huánuco to the Department of Puno

The grey-browed brushfinch inhabits the interior and edges of humid montane forest and secondary forest. It ranges in elevation between in Venezuela, between in Colombia, between in the northern part of Ecuador, and between and locally much lower in the southern part. In far northwestern Peru it ranges between and elsewhere in the country between .

Behavior Movement

The grey-browed brushfinch is a year-round resident.

Feeding

The grey-browed brushfinch's diet has not been studied. It typically forages singly or in pairs. It forages on the ground, usually under cover, scratching in leaf litter with its bill.

Breeding

The grey-browed brushfinch's breeding season has not been defined. However, it includes June in Colombia, July through September in Ecuador, and June, August, and November in Peru. Nothing else is known about the species' breeding biology.

Vocalization

The grey-browed brushfinch's song is "a high, sibilant series of thin whistles with short spaces between separate phrases (often of three elements), e.g. weseer-twee twesee? Sewtsee? Weseer-twee tweswee? Sewtswee?...". Its calls include "a high ti and a tseer".

Status

The IUCN has assessed the grey-browed brushfinch as being of Least Concern. It has a very large range; its population size is not known and is believed to be decreasing. No immediate threats have been identified. It is considered uncommon to common in Venezuela, common in Colombia, "widespread" in Ecuador, and fairly common in Peru.

References