The Ocellated Tapaculo (Acropternis orthonyx) is a large bird found in the northern Andes in South America. It is a highly distinctive tapaculo; traditionally united with these in the "Rhinocryptidae", this presumed family is paraphyletic and most of the tapaculos belong in the Formicariidae with the ground antbirds which they resemble. It may well be, but is not entirely clear, that the present species would also be belong in the Formicariidae.
This passerine averages 8.3-8.7 in (21-22 cm) in length and between 2.8-3.5 oz (80 and 100 gram). The bird is mostly black with large white spots, a brown flank, and a reddish head and throat. A call, apparently given by birds to to announce their presence to conspecifics, is described as "loud, emphatic WHEEUW! whistle" which as it seems can be heard from a long distance .
It is sometimes divided into two subspecies: Acropternis orthonyx infuscata is found in the mountains of Ecuador and northern Peru. The nominate subspecies A. o. orthonyx ranges further north, from the Cordillera Central and Cordillera Oriental of Colombia to the mountains of northwestern Venezuela, with small populations also present in the Cordillera Occidental (in Antioquia and the Páramo de Frontino at least). It is not usually found on the Amazonian slope of the East Colombian and Venezuelan mountains it inhabits; on the Cordillera Oriental it is only known so far in a few places between 8,200-10,000 ft (2,500-3,000 m) ASL. The northern and southern populations are barely distinguishable and many authors accept no subspecies at all.
It favors humid and rather low-growing forest with canopy heights of about 50-80 ft (15-25 m). Dominant trees can include for example Brunellia, Hieronyma rufa (Phyllanthaceae), Ocotea calophylla (Lauraceae), oaks (Quercus), glorytrees (Tibouchina) and Weinmannia, usually heavily overgrown with epiphytes. More important is the presence of a tangled understory with abundant stands of South American mountain bamboo (Chusquea), forming an impenetrable thicket together with other plants such as Geonoma weberbaueri palms or Ericaceae shrubs. Due to its dependence on bamboo thickets which only grow in clearings it seems to tolerate selective logging well and may actually benefit from it.
The Ocellated Tapaculo eats plant material and arthropods, which it digs up using both feet simultaneously. It is usually encountered in pairs or alone, hopping through bamboo along the forest floor. Preferring to stay close to the ground, it is more often heard than seen. It is possible to attract Ocellated Tapaculos with recorded or imitated calls, which they will approach to investigate from several kilometers away. Though shy and retiring and affected by habitat destruction like all forest birds of the tropical Americas, it is common enough to be considered a Species of Least Concern by the IUCN.