Tapaculo

The tapaculos are a group of small suboscine passeriform birds with numerous species, found mainly in South America and with the highest diversity in the Andean regions. Three species, the Choco, the Pale-throated and the Silvery-fronted Tapaculo, are found in southern Central America.

Description
Tapaculos are small to medium-sized birds, with a total length ranging from 10–24 cm (4–9½ in). These are terrestrial species that fly only poorly on their short wings. They have strong legs, well-suited to their habitat of grassland or forest undergrowth. The tail is cocked and pointed towards the head, and the name tapaculo possibly derives from Spanish for "cover your behind". Another possible explanation is that it originates from the Chilean name for the White-throated Tapaculo, simply Tapaculo, which is an onomatopoeic reference to its commonly heard song.

While the majority of the family are small blackish or brown birds there are some larger and more colourful species. All tapaculos are skulking birds that frequently stay low in dense vegetation, even the larger, colorful species, and this renders them difficult to see. They are best located and – in the case of Scytalopus spp. – identified by their vocalisations.

They feed on insects, seeds and other soft plant material with their pointy bills, and will scratch on the ground like a pheasant. Most species lay two or three white eggs in a covered location, whether it be a burrow, a hole in a tree, or a domed nest.

Threats and conservation
Some species have highly localized distributions, and being poor fliers, they easily become isolated in small populations. BirdLife International currently (2007) consider one species vulnerable (Scytalopus panamensis), three species endangered (S. iraiensis, S. rodriguezi and S. robbinsi), and two species critically endangered (Eleoscytalopus psychopompus and Merulaxis stresemanni). The two critically endangered species are restricted to Atlantic forest of eastern Brazil, and were only recently rediscovered after several years without any records.

Taxonomy
The tapaculos were traditionally placed in a distinct family Rhinocryptidae; more recent research (Irestedt et al. 2002, Rice 2005a,b) indicates that according to analysis of mt and nDNA sequence data, the tapaculos might be better merged into the Formicariidae as tribe Rhinocryptini, as they are closer to the antthrushes than either is to the true antpittas.

Alternatively, the latter might be raised to family status. In this case, it would be possible to maintain the tapaculos as a separate family too, but it would seem altogether more warranted to consider them a subfamily of the Formicariinae sensu stricto, which would be called Rhinocryptinae.

Whether this latter approach, the placement as a tribe in a tapaculo-antthrush Formicariinae subfamily, or maintenance as a separate family is to be preferred depends on whether the true antpittas are closer to the tapaculos and true antbirds, or rather to the Pittasoma "gnatthrushes" and other gnateaters and the true antbirds. There are some, albeit very tentative, indications that the latter may indeed be the case, which would be reflected in the placement of the tapaculos as subfamily Rhinocryptinae, with the Formicariinae being restricted to the true antthrushes (Rice 2005a).

It must be noted that apparently not all tapaculo genera would have to be moved to the formicariids (Irestedt et al. 2002). As the type genus Rhinocrypta certainly would, any distinct genera (such as the peculiar crescent-chests) would need a new family name.

Taxonomy of Scytalopus
The species-limits within the genus Scytalopus is among the most complex matters in Neotropical ornithology. They are highly cryptic, and identification using visual features often is impossible. Vocal and biochemical data is typically needed to clarify the taxonomic status of the various populations. Several new species have been described in recent years (e.g. S. stilesi and S. rodriguezi from Colombia). The Brazilian taxa are similarly complex with several recently described species and considerable confusion surrounding the use of the scientific name Scytalopus speluncae.

Additionally, still undescribed species are known to exist (e.g. the "Apurimac Tapaculo" and "Millpo Tapaculo"; both from Peru), while some species as currently defined actually may include several species (e.g. the southern population of the Large-footed Tapaculo may represent a yet undescribed species). The confusing situation is perhaps best illustrated by the fact that only 10 species were recognized in this genus in 1970 (Krabbe & Schulenberg, 2003), while the figure now is more than four times as high.

Species list
Genera allied with antthrushes
 * Genus Pteroptochos, the huet-huets
 * Black-throated Huet-huet, Pteroptochos tarnii
 * Chestnut-throated Huet-huet, Pteroptochos castaneus
 * Moustached Turca, Pteroptochos megapodius
 * Genus Scytalopus (some 40-45 species)
 * Genus Scelorchilus
 * White-throated Tapaculo, Scelorchilus albicollis
 * Chucao Tapaculo, Scelorchilus rubecula
 * Genus Rhinocrypta
 * Crested Gallito, Rhinocrypta lanceolata
 * Genus Liosceles
 * Rusty-belted Tapaculo, Liosceles thoracicus

Probably a distinct family N.N.
 * Genus Melanopareia, the crescent-chests
 * Collared Crescent-chest, Melanopareia torquata
 * Olive-crowned Crescent-chest, Melanopareia maximiliani
 * Elegant Crescent-chest, Melanopareia elegans
 * Maranon Crescent-chest, Melanopareia maranonica
 * Genus Teledromas
 * Sandy Gallito, Teledromas fuscus

Placement unresolved
 * Genus Psilorhamphus
 * Spotted Bamboowren, Psilorhamphus guttatus
 * Genus Merulaxis, the bristlefronts
 * Slaty Bristlefront, Merulaxis ater
 * Stresemann's Bristlefront, Merulaxis stresemanni
 * Genus Eleoscytalopus (formerly in Scytalopus)
 * White-breasted Tapaculo, Eleoscytalopus indigoticus
 * Bahia Tapaculo, Eleoscytalopus psychopompus
 * Genus Eugralla
 * Ochre-flanked Tapaculo, Eugralla paradoxa
 * Genus Myornis
 * Ash-coloured Tapaculo, Myornis senilis
 * Genus Acropternis
 * Ocellated Tapaculo, Acropternis orthonyx