Rufous-tailed Antthrush

Exhibits a robust, plump silhouette typical of ground-dwelling suboscines adapted to walking on the forest floor. The total body length ranges between 19 and 20 cm, with an average body mass spanning from 65 to 85 g. The upperparts are predominantly a deep olive-brown, which provides an abrupt and sharp contrast with the distinctive, intensely colored rufous-chestnut rump and rectrices, serving as the species´ primary diagnostic field mark. The ventral surface displays a disruptive and cryptic plumage pattern, consisting of a whitish or pale buff background heavily patterned with thick, dark brownish-black longitudinal streaks running from the breast down through the flanks. The facial pattern includes an inconspicuous pale buff superciliary streak extending behind the ocular region, coupled with pale malar feathers finely bordered by dark edges. The bill is straight, stout, and blackish with a slightly paler mandibular base, while the legs and tarsi are remarkably elongated, adapted for ambulatory locomotion, and washed in a pale pinkish-brown hue. Sexual dimorphism in plumage is virtually absent.

Geographical distribution: Restricted to the moist ecological zones of the southern Atlantic Forest biome in eastern South America. It occurs in fragmented montane regions across southeastern and southern Brazil, including the states of Minas Gerais, Espírito Santo, Rio de Janeiro, São Paulo, Paraná, Santa Catarina, and northeastern Rio Grande do Sul. Outside Brazilian borders, the southwestern periphery of its geographical range extends into the extreme northeastern sector of Argentina, specifically confined to the interior humid forests of the Misiones province.

Habitat: Inhabits the shadowy understory of humid montane evergreen forests, cloud forests, and moist subtropical woodlands characterized by high atmospheric moisture. The altitudinal range generally falls between 800 and 2,200 m above sea level, though southern populations can occur at significantly lower elevations, occasionally reaching near sea-level terrain. The species demands well-preserved, mature primary or mature secondary forest stands featuring a closed canopy, tangled patches of native bamboo such as Chusquea, arborescent ferns, and a thick, undisturbed blanket of moist leaf litter resting upon shaded terrain.

Feeding: Sustains an exclusively carnivorous, invertebrate-based diet dominated by ground-dwelling organisms. It searches the forest substrate systematically, using its sharp bill to lift, flick, and toss aside decayed leaves, decomposing bark, and surface debris. Common prey items consist of adult and larval coleopterans, spiders, ants, centipedes, earthworms, small terrestrial snails, and orthopterans. The foraging strategy is deliberate, punctuated by short walks and brief pauses where the bird surveys the cleared soil surface to capture exposed prey items before they burrow or take shelter.

Behavior: Highly secretive, terrestrial, and solitary in nature, occasionally found moving in territorial pairs. It rarely flies, reserving short, frantic wingbeats strictly for crossing minor physical obstacles or fleeing direct predatory pursuit. When walking along the substrate or navigating fallen moss-covered trunks, it assumes a distinctive posture, cocking and rhythmic pumping its short tail up and down. Because visual contact in the dense vegetation is exceptionally difficult, its presence is most reliably confirmed through its penetrating vocalization: an accelerating musical sequence of hollow, resonant notes delivered from low horizontal branches, stumps, or elevated root systems situated close to the ground.

Nesting: Breeds discreetly by taking advantage of pre-existing cavities situated within the forest structure. The nest is placed inside natural hollows of decaying trunks, rotten stumps, crevices between mossy boulders, or within the fibrous mass of large tree ferns like Dicksonia sellowiana, usually below two meters of height. The internal chamber is lined with a pad composed of skeletonized dry leaves, plant fibers, and fine rootlets. A standard clutch consists of 2 eggs, uniform creamy-white in color, which are incubated for an estimated span of 17 to 19 days. Parental care is biparental, with both adults taking active turns warming the eggs and delivering mashed arthropods to the altricial nestlings until they fledge.

Conservation status: Classified globally as Least Concern (LC) by the International Union for Conservation of Nature (IUCN). Although it retains a relatively broad distribution across its montane strongholds, local populations are continually threatened by habitat loss, edge effects, and forest fragmentation driven by agricultural expansion and infrastructure development throughout the fragile Atlantic Forest biome, making the protection of large, contiguous forest tracts essential for its long-term viability.