Rusty-margined Guan

Characterized by a slender profile and a total body length ranging from 21.5 to 28.7 inches (55 to 73 centimeters), this medium-sized cracid weighs between 750 and 1000 grams. The plumage is predominantly a deep dark olive-brown, accentuated by distinctive rusty or rufous-chestnut margins on the wing coverts and scapulars, which provide its common name. A prominent, variable whitish or silvery-grey superciliary stripe runs above the dark eye, contrasting with the dark crown. The bare throat features a conspicuous, bright red dewlap of distensible skin, while the bill is dark greyish-black, and the legs present a reddish-brown coloration.

Geographical distribution: Occurs widely across eastern and central South America. Its geographic range encompasses a vast portion of Brazil, extending from the northeastern state of Maranhão southward to Rio Grande do Sul, and westward into Mato Grosso. The species is also found in eastern Paraguay and reaches its southernmost distribution limit in northeastern Argentina, specifically within the province of Misiones, aligning with the borders of the southern Atlantic Forest.

Habitat: Inhabits diverse forest ecosystems, displaying a higher tolerance for habitat alteration than most of its congeners. It is frequently observed in humid lowland forests, gallery forests, mature secondary growth, and forest edges. It also frequents transitional biomes such as the Cerrado and Caatinga, as well as shade-grown coffee plantations and eucalyptus groves, provided there is sufficient canopy cover to offer protection and foraging substrates.

Feeding: Highly frugivorous, playing a fundamental role as an active seed disperser within its ecological communities. Its diet relies heavily on the fruits of various native trees and palms, particularly those of the genus Syagrus and the heart-of-palm Euterpe edulis. To complement this fruit-based diet, it consumes tender leaves, flowers, buds, seeds, and occasionally hunts for small invertebrates such as insects and spiders on the forest floor or among the foliage.

Behavior: Primarily diurnal and arboreal, although it frequently visits the ground to forage or swallow grit to aid in gizzard digestion. It is typically seen in pairs or small family groups of three to five individuals. Active during dawn and dusk, it produces loud, harsh, trumpeting vocalizations to establish territory. During the breeding season, males perform a characteristic drumming display created by rapid, mechanical wing-vibrations during short flights between perches.

Nesting: Constructs its nest at low to medium heights, typically 6.5 to 16 feet (2 to 5 meters) above the ground, hidden within dense foliage, vines, or epiphytes. The nest is a flat, somewhat fragile platform composed of dry twigs, sticks, and lined with green leaves. The female typically lays a clutch of 2 to 3 chalky white eggs. The incubation period lasts around 28 days and is performed solely by the female, while the male remains nearby to defend the nesting territory from predators.

Conservation status: Classified as Least Concern (LC) on the IUCN Red List of Threatened Species. Although it remains widespread and adaptable to secondary habitats, local populations face ongoing threats from habitat fragmentation, agricultural expansion, and subsistence hunting. Protecting native forest corridors and enforcing hunting regulations are vital conservation strategies to ensure the long-term survival of this species across its highly fragmented range.