Timberline wren
The timberline wren ("Thryorchilus browni") is a species of bird in the family Troglodytidae. It is found in Costa Rica and western Panama. Taxonomy and systematics. The timberline wren is the only member of genus "Thryorchilus", but its taxonomy at the subspecies level is unsettled. The International Ornithological Committee (IOC) considers it to be monotypic. The Cornell Lab of Ornithology's "Birds of the World" lists three subspecies, but notes that this treatment is disputed and that timberline wren should be "perhaps better considered monotypic." The Clements taxonomy and the Handbook of Birds of the World list the  same three subspecies without comment. The three disputed subspecies are the nominate "Thryorchilus browni browni", "T. b. ridgwayi", and "T. b. basultoi". Description. The timberline wren is long and weighs . The adult of the nominate subspecies has rich chestnut brown crown and upperparts and a reddish brown tail with thin dark bars. It has a broad gray-white supercilium, a chocolate brown stripe behind the eye, and grayish cheeks with narrow black markings. Its throat and chest are grayish white, its upper belly a mottled grayish white, its lower belly brown, and its flanks and vent area reddish brown. The  juvenile is grayer below with a scalloped appearance. "T. b. ridgwayi" is larger than the nominate and has deeper reddish brown upperparts. "T. b. basultoi" has a wider supercilium, whitish markings on the upperparts and the sides of its neck, and has whiter underparts. Distribution and habitat. The timberline wren's range is disjunct, and spans from central Costa Rica south to northern Panama. "T. b. ridgwayi" is found on Volcán Turrialba, Volcán Irazú, and adjacent areas in central Costa Rica. "T. b. basultoi" is found in the Cordillera de Dota of south central Costa Rica. The nominate "T. b.  browni" is found on Volcán Barú, Volcán de Chiriquí, and Cerro Copete in western Panama. The timberline wren inhabits "páramo" and near-"páramo" moorland at the upper edge of tree line, and is partial to bamboo thickets. In elevation it mostly ranges between but can be found as low as . Behavior. Feeding. The timberline wren typically forages on or near the ground, sometimes fluttering to pick prey from leaves and creeping along mossy branches. Its diet includes small insects, caterpillars, and spiders. Breeding. The timberline wren's breeding season in Costa Rica spans from April to June. Its nest is a  hollow ball constructed of bamboo leaves lined with finer material. It has a side entrance and is placed up in bamboo or a shrub. The typical clutch size is two. Vocalization. The timberline wren's song is quite different from that of any "Troglodytes" wren; it is a repeated "series of half a dozen scratchy, warbling notes, lasting 2–3 seconds". Its call is "a harsh scolding 'churr'". Status. The IUCN has assessed the timberline wren as being of Least Concern. Though it has a restricted range, it is considered common to abundant in its habitat. Much of its range is  in national parks and receives little human pressure.