It is a relatively large passerine within the South American grassland finches, measuring approximately 20–23 cm in length, with a robust body and a long, broad, rounded tail that is particularly noticeable when perched or in flight. One of its most distinctive features is the bright orange bill with a blackish upper mandible, adapted for handling hard seeds. The sides of the head are dark gray or slate-colored, contrasting with the grayish olive upperparts. The wings appear slightly brighter green, with a distinct yellow patch on the shoulder area. Underparts are mostly grayish, with a paler, almost whitish abdomen, while the flanks and undertail coverts tend to be brownish. Juveniles differ by showing strong streaking on the breast and yellowish tones on the throat and chest, which gradually fade as the bird matures.
Geographic distribution: It is widely distributed across the southern regions of South America, occurring from southeastern Brazil and eastern Bolivia southward through Paraguay and Uruguay and extending into much of Argentina, reaching northern Patagonia. The species is particularly associated with lowland plains and open landscapes, including agricultural areas and wetland margins. In some Andean regions it can occur at elevations above 2,500 m, although most populations inhabit lowlands and extensive grassland systems.
Habitat: This species inhabits humid grasslands, marshes, seasonally flooded savannas, and tall grass fields, where dense vegetation provides both shelter and food resources. It is commonly found in reedbeds, marsh edges, lagoons, and open areas with scattered shrubs. The species can also tolerate human-modified environments, such as cattle pastures, roadside vegetation, and agricultural fields, especially when tall grasses remain present. In these habitats it frequently moves through the lower vegetation layers, using taller grasses, bushes, or fence posts as vantage points.
Diet: Its diet is omnivorous but predominantly granivorous, consisting largely of seeds from grasses and other herbaceous plants typical of open grasslands. However, it also consumes a considerable proportion of insects and other arthropods, particularly during the breeding season when energy demands increase. Recorded prey include ants, beetles, caterpillars, spiders, and orthopterans. Dietary studies based on stomach content analyses indicate that during certain seasons insects may form a significant portion of the diet, complementing the consumption of seeds and other plant material.
Behavior: It is typically observed alone or in pairs, although small groups may occasionally gather where food is abundant. The species is territorial during the breeding season. Individuals frequently perch on tall grasses, shrubs, or fence posts, from where they deliver their characteristic song. Foraging occurs mainly on the ground or among low vegetation, where the birds walk or hop while searching for food. Flight is generally short and somewhat heavy, and birds often dive quickly back into dense vegetation after landing. Its vocalization consists of clear, musical phrases repeated several times, used in territorial displays and communication.
Breeding: The breeding season usually extends from late winter through the austral summer. Nests are built close to the ground, concealed among dense clumps of tall grasses, which provide protection against predators. The nest is cup-shaped and constructed from plant fibers, dry stems, and leaves, with a softer inner lining. Females typically lay two to three eggs per clutch, pale in color with brownish markings. In favorable conditions, pairs may produce more than one brood during the same breeding season.
Conservation status: The species is currently considered Least Concern, largely due to its wide distribution and generally stable populations. It also shows a notable ability to adapt to agricultural landscapes and modified grasslands, which has helped maintain its numbers in many regions. Nevertheless, the degradation of wetlands and the loss of native grasslands could negatively affect local populations if these processes intensify.
Author of this compilation: EcoRegistros – 06/03/2026