Tapaculos

(Rhinocryptidae)

Class Aves

Order Passeriformes

Suborder Tyranni (Suboscines)

Family Rhinocryptidae

Thumbnail description
Wren-to thrush-sized birds, terrestrial or skulking in dense undergrowth; bill straight, in some species elevated at base; tail short to medium and carried half-cocked; large feet; most species dull-colored

Size
3.9–9.1 in (10–23 cm); 0.37–6.53 oz (10.4–185 g)

Number of genera, species
12 genera; 54 species

Habitat
Undergrowth and ground of forest and scrub, often bamboo thickets; a few species prefer bunch grass, rocks, or tall grass

Conservation status
Critically Endangered: 2 species; Endangered: 1 species; Vulnerable: 1 species; Near Threatened: 5 species

Distribution
Central and South America

Evolution and systematics

Tapaculos are among the most primitive of passerine birds. Based on both DNA and morphological comparisons, their closest relatives are believed to be the ground antbirds (Formicariidae, sensu stricto), particularly the genera Formicarius and Chamaeza, and the gnateaters (Conopophagidae). Together, these three form the superfamily Formicarioidea.

Twelve genera with 54 species are currently recognized, but one form of the genus Melanopareia that is currently treated as a subspecies may deserve full species rank, and the taxonomy of the genus Scytalopus is far from resolved. Several species are so alike that they cannot be told apart by external morphology, not even in the hand, rendering Scytalopus the most problematic of all bird genera. The species differ genetically, in vocalizations, elevational distribution, and frequently in body mass (but often not in other measurements), but plumage differences have not evolved as an important part of species recognition, probably owing to the dark haunts of these birds. Voices of several yet undescribed forms are known, and it seems possible that as many as ten or more species will be recognized through further taxonomic revision and description of new taxa.

Three genera are so aberrant that they may not belong in the same family as the others. Melanopareia and possibly with it the poorly studied Teledromas differ in so many characteristics that they are probably best placed in a family of their own. The monotypic Psilorhamphus has been variously placed with gnatwrens, wrens, and true antbirds, but an anatomical study showed that it shares some characteristics with the tapaculos, with which it was then placed. However, its affinities may yet be shown to lie elsewhere.

Physical characteristics

Tapaculos comprise a rather diverse array of forms with only a few common characteristics. They all have nostrils covered by a tactile flap and possess a sternum with four posterior notches. A similar sternum is only found in the gnateaters and some ground antbirds, both families being close relatives of the tapaculos. Presumably as a consequence of their limited use of flight, tapaculos have no keel on the sternum. The bill is straight and fairly weak, in some species with an elevated base.

The bones are exceptionally soft, and in the genus Scytalopus the brain case never ossifies at all. Except for

Melanopareia and Teledromas the humerus is distinctly curved. Melanopareia (and possibly Teledromas) also differ by the shape of the stapes, a small bone in the inner ear. Most tapaculos have disproportionally strong feet and large claws. Acropternis has a very long hind claw, the function of which has been disputed.

The feather tract of the flank is fused with that of the back except in Melanopareia and Teledromas. The body is densely feathered, particularly on the rump, and the feathers fall off easily, probably to confuse predators. The feathers of the lores are stiff and erect in many tapaculos, protecting the eyes from dirt and ants. These feathers are most evolved in Merulaxis, where they are greatly elongated and allow the bird to see while boring its head into litter.

Tapaculos are nearly flightless. Their wings are short and rounded with ten primary flight feathers. The tail, usually carried half-cocked, is composed of a variable number of feathers ranging from eight to 14, the number varying even within the same population. The more or less graduated tail is decidedly short in many species, but medium long in some forms. The sexes are fairly similar in most species, with females appearing somewhat smaller and duller. In Merulaxis, however, the sexes are distinctly differently colored. Plumage colors are generally dull, grayish or brown, and without marked pattern, but Melanopareia exhibits some rather bright chestnut, black and white colors in striking patterns.

Distribution

Tapaculos are distributed from Costa Rica through South America to Tierra del Fuego. The large majority of species are montane or live in temperate regions. Only one tapaculo, Liosceles, inhabits the Amazonian lowlands. Six species of Scytalopus and Merulaxis, and the peculiar Psilorhamphus, are confined to southeastern Brazil, some of them also occurring in adjacent parts of Argentina and Paraguay. Two of the four species of Melanopareia are found in the arid lowlands of northwestern Peru and southwestern Ecuador, the other two in the arid parts of Brazil, Paraguay, Bolivia and northern Argentina. Teledromas occurs in desert scrub in western Argentina; Rhinocrypta in the chaco and drier part of the pampas.

In the Andes the most widespread genus, Scytalopus, reaches its greatest diversity. Up to five species may occur on a single slope, some showing strikingly sharp altitudinal replacements. In Central America and north-east of the "Táchira Gap" in the Andes near the border of Colombia and Venezuela, the diversity is smaller. In the coastal mountains of Venezuela only a single Scytalopus species is found, none on the Tepuis or in the Guianas. Only two genera, Myornis and Acropternis are endemic to the northern Andes. Three genera, Pteroptochos, Scelorchilus, and Eugralla are endemic to the southern Andes.

Habitat

Tapaculos occur in a wide range of habitats. Most frequent dense undergrowth in humid or wet montane forest, and a few species have even adapted to tussock grassland and scree adjacent to forest in Patagonia and above treeline in the Andes. One inhabits the lowland forest of Amazonia, another is confined to uniform stands of tall grass and bulrush in south Brazilian marshes. A few inhabit semi-humid forest and scrub, and five species prefer arid scrub.

Behavior

Tapaculos live such secluded lives that little is known about their behavior. They try to avoid the open so much that in most cases they can be observed only briefly. Except for Acropternis, which hops slowly on the forest floor, most of the large tapaculos walk or run, making sudden halts. The fairly small Teledromas also runs, taking long strides as it speeds over the bare ground. Most of the small species are more constantly active and tend to hop rather than run while on the ground, and all tapaculos hop when moving in the vegetation above ground. Most tapaculos can be very swift when surprised and have been observed attacking a tape-recorder after playback of their song, but both Acropternis and Liosceles appear to be always slow-moving. Acropternis is perhaps best described as lethargic.

Feeding ecology and diet

Tapaculos take a variety of food, but mainly feed on insects and spiders. It has recently been found that some add a substantial amount of berries to their diet, at least seasonally.

The foraging mode varies between species. Pteroptochos and Scelorchilus walk or run quickly, then stop to scrape the ground with one foot, or with both feet simultaneously, throwing earth and leaves backwards in an awkward jump. Such "jumpscratching" has also been seen in Eugralla and is frequently seen in Acropternis. The grotesquely long hind claw of the latter may be an adaptation to this behavior. Scytalopus tapaculos glean prey from moss, litter, earth and rotting vegetation as they move along quickly in the undergrowth or on the ground with a mouse-like appearance. Myornis perch gleans clumps of bamboo. Merulaxis has been seen digging its head into leaf litter on the ground. Liosceles picks prey from the ground as it walks slowly, occasionally scratching with one foot, and appears to feed entirely on bugs. Rhinocrypta and Teledromas feed only on the ground, running quickly to cross open ground, the latter sometimes scratching the ground with one foot. Melanopareia runs on the ground like Teledromas, but also perch gleans insects while working through low branches like a Synallaxis spinetail. Psilorhamphus mainly hops through viny thickets of bamboo.

Reproductive biology

Some, perhaps all, tapaculos might form permanent pair bonds. Most small birds quickly replace a lost mate, and tapaculos are no exception. In Scytalopus tapaculos, a new male appears almost immediately after the old one has been removed.

Although nests of 18 of the 54 species of tapaculos are known, details of nesting have been studied in only a single species, Rhinocrypta lanceolata.

A few build cup nests, but most construct closed nests with a side entrance or place their nest in a tunnel. The nest is fairly soft, made of root fibers, grass, moss, and a few small twigs. Nests of Eugralla and Rhinocrypta are bulky. Rhinocrypta, Eugralla, and sometimes Melanopareia place their nest above ground, but most tapaculos nest at the end of a tunnel or hollow trunk. Tunnels may be dug by the bird or an abandoned rodent burrow may be used.

Most tapaculos lay two to three eggs that are white, large for the size of the bird, rounded and lacking in sheen. Melanopareia is an exception, as it lays ovoid and spotted eggs.

The incubation period is 15–17 days and the gestation period is 14–15 days for Rhinocrypta. Males take part in the incubation in some species, but apparently not in Scytalopus, where brood patches have been found only in females.

The young hatch naked. Both parents care for nestlings, but apparently fledglings are sometimes fed by the female alone.

Conservation status

Two species of tapaculo are listed as Critically Endangered and may have gone extinct over the last two decades. They

are Merulaxis stresemanni and Scytalopus psychopompus, both restricted to small areas in coastal Bahía in eastern Brazil, where deforestation continues at an alarming rate. The former has not been seen since 1995 and the latter not since the 1980s. Hope for their survival is slight.

The recently discovered Scytalopus iraiensis inhabits the few remaining rushy marshes in eastern Paraná in southern Brazil, a habitat under constant pressure from human development. It is considered Endangered and needs human support to insure its survival.

Scytalopus panamensis is confined to the Tacarcuna Massif in the Darién gap on the border of Panama and Colombia. Owing to forest clearance within its very restricted range, the species is considered Vulnerable. It is still common, but if the Panamerican Highway is completed as planned, the pressure on its habitat will accelerate drastically.

Five species are considered Near Threatened owing to small ranges and continuing loss of habitat. These are Scytalopus novacapitalis of swamp gallery forest in a small area in central Brazil; Scytalopus indigoticus, Merulaxis ater, and Psilorhamphus guttatus, all confined to the rapidly dwindling Atlantic forests of east and southeast Brazil; and Melanopareia maranonica of dense arid scrub in a small area in the Río Marañón drainage in northern Peru, a habitat increasingly disturbed and giving way to agriculture.

Additionally, Scytalopus robbinsi, which is confined to an area in southern Ecuador that will be nearly completely deforested over the next few decades unless protective measures are taken, should be added to the species of concern. Several other species of Scytalopus have very small ranges and are therefore vulnerable but not presently considered to be at risk.

Significance to humans

Tapaculos are small and do not occur in concentrations, so although they taste good, they have never been hunted. Their secluded existence is revealed only through their loud calls, giving rise to onomatopoetic local names, the name tapaculo itself being apparently derived from the distinctive "tá-pa-koo" call of Scelorchilus albicollis. The loud voice of Scelorchilus rubecula figures in folklore in southern Chile, and the distinctive voice of Liosceles heard through large parts of the Amazon basin is so loud that it must be part of some folklore. No tapaculo held in captivity has ever been reported except for a single Acropternis orthonyx, which survived for only a few months in New York Zoo.

Species accounts

List of Species

Black-throated huet-huet

Pteroptochos tarnii

taxonomy

Hylactes tarnii King, 1831, Chiloé Island, and Port Otway, Gulf of Penas, Chile.

other common names

English: Huet huet; French: Tourco huet-huet; German: Schwarzkehl-Huëthuët; Spanish: Huet-huet del Sur.

physical characteristics

9 in (23 cm); 5.3–6.3 oz (150–180 g). Crown, forehead, and breast dark chestnut. The rest of body is black.

distribution

Southern Chile from Río Bío Bío to Brunswick Peninsula, and adjacent Argentina from Neuquén to northwestern Santa Cruz.

habitat

Humid forest.

behavior

Terrestrial.

feeding ecology and diet

Walks slowly. Flips debris with bill and sometimes scrapes the ground with one foot. Feeds on invertebrates and berries.

reproductive biology

Nest placed in excavated tunnel or a hollow trunk. Two or three eggs.

conservation status

Not threatened.

significance to humans

None known.

Moustached turca

Pteroptochos megapodius

taxonomy

Pteroptochos megapodius Kittlitz, 1830, Valparaiso, Chile.

other common names

English: Turco; French: Tourco à moustaches; German: Turco; Spanish: Huet-huet Turco.

physical characteristics

8.9 in (22.5 cm). Brown. Brow and broad moustache are whitish. Belly barred dusky.

distribution

P. m. atacamae: Northern Chile in Atacama. P. m. megapodius: Central Chile from Coquimbo to Concepción.

habitat

Semi-arid scrub.

behavior

Terrestrial.

feeding ecology and diet

Walks and runs, then stops and scrapes the ground with one foot.

reproductive biology

Nest placed in excavated tunnel. Two, rarely three eggs.

conservation status

Not threatened.

significance to humans

None known.

Chucao tapaculo

Scelorchilus rubecula

taxonomy

Pteroptochos rubecula Kittlitz, 1830, Concepción, Chile.

other common names

French: Tourco rougegorge; German: Rotkehl-Tapaculo; Spanish: Tapacola Chucao.

physical characteristics

7.3–7.5 in (18.5–19 cm); 1.5–1.6 oz (43–45 g). Brown. Throat and breast orange. Belly gray with irregular black and white bars.

distribution

S. r. rubecula: Southern Chile from Colchagua to Aysén, and adjacent Argentina from Neuquén to Chubut. S. r. mochae: Southern Chile on Mocha Island.

habitat

Bamboo thickets in humid forest and woodland.

behavior

Mainly terrestrial.

feeding ecology and diet

Walks on the ground. Food includes invertebrates and berries.

reproductive biology

Nest placed in excavated tunnel. Two or three eggs.

conservation status

Not threatened.

significance to humans

None known.

Crested gallito

Rhinocrypta lanceolata

taxonomy

Rhinomya lanceolata Geoffroy Saint-Hilaire, 1832, Patagonia, on the banks of the Río Negro.

other common names

French: Tourco huppé; German: Schopfgallito; Spanish: Gallito Copetón.

physical characteristics

8.3 in (21 cm); 1.8–2.3 oz (52–64 g). Gray. Crest rufous with thin white streaks. Sides and flanks chestnut. Lower belly is white.

distribution

R. l. saturata: Southeastern Bolivia, and Paraguay. R. l. lanceolata: Argentina from Catamarca and Buenos Aires to Río Negro.

habitat

Semi-arid thorny woodland.

behavior

Mainly terrestrial.

feeding ecology and diet

Walks on the ground or hops through low bushes.

reproductive biology

Nest globular and bulky with a side entrance, placed in bush. Two eggs. Incubation takes 16–17 days, gestation is 14–15 days.

conservation status

Not threatened.

significance to humans

None known.

Rusty-belted tapaculo

Liosceles thoracicus

taxonomy

Pteroptochus thoracicus Sclater, 1865, Salto do Girao, Rio Madeira, Brazil.

other common names

French: Tourco ceinturé German: Brustband-Tapaculo; Spanish: Gallito Pardo.

physical characteristics

7.7 in (19.5 cm); 1.4–1.5 oz (39–42 g). Upper coloring is dark gray-brown. Has narrow white brow. Sides of neck are gray. Throat and breast are white, bordered on the sides by a black line and with a more or less complete rufous breast band. Belly is barred black, rufous and white.

distribution

L. t. dugandi: Southeast Colombia and adjacent western Brazil on the Rio Solimoes. L. t. erithacus: From east Ecuador south to the mouth of Río Urubamba, eastern Peru. L. t. thoracicus: Southeast Peru and southwest Amazonian Brazil, east to Rio Tapajóz.

habitat

Humid forest.

behavior

Terrestrial.

feeding ecology and diet

Walks and hops slowly. Feeds almost entirely on bugs.

reproductive biology

Nest is globular with top entrance and placed underground among roots.

conservation status

Not threatened.

significance to humans

None known.

Slaty bristlefront

Merulaxis ater

taxonomy

Merulaxis ater Lesson end of 1830 or beginning of 1831, Mexico; error, Rio de Janeiro substituted by Hellmayr (1924).

other common names

French: Mérulaxe noir; German: Bürstentapaculo; Spanish: Galltio Gris.

physical characteristics

7.3 in (18.5 cm); 1.2–1.3 oz (33–37 g). Loral feathers are stiff and elongated. Tail is fairly long, black. Male is uniform dark gray. Female is brown, palest below.

distribution

Southeast Brazil from south Bahía to east Paraná.

habitat

Humid forest.

behavior

Terrestrial, usually in pairs, occasionally ascending a bush or log to look out.

feeding ecology and diet

Walks, hops and runs. Bores head into litter.

reproductive biology

Unknown.

conservation status

Near Threatened.

significance to humans

None known.

Collared crescentchest

Melanopareia torquata

taxonomy

Synallaxis torquatus Wied, 1831, Campo Geral of inner Brazil = campos on the Bahia-Minas Gerais border.

other common names

French: Cordon-noir à col roux; German: Zimtbandvogel; Spanish: Gallito de Collar.

physical characteristics

5.7 in (14.5 cm); 0.56–0.81 oz (16–23 g). Tail is fairly long. Above gray-brown (crown black in bitorquata), nuchal collar rufous, concealed interscapular patch white. Brow white, sides of head black. Throat buff, breast band black, rest of underparts dark reddish brown, palest on lower belly.

distribution

M. t. torquata: Eastern Brazil. M. t. rufescens: Central Brazil and northeastern-most Paraguay. M. t. bitorquata: Eastern Bolivia.

habitat

Semi-arid scrub.

behavior

Alone or in pairs. Runs on the ground and hops in low parts of the vegetation.

feeding ecology and diet

Unknown.

reproductive biology

Unknown.

conservation status

Not threatened.

significance to humans

None known.

Spotted bamboowren

Psilorhamphus guttatus

taxonomy

Leptorhynchus guttatus Ménétriès, 1835, Cuiabá-Sabará, Minas Gerais, Brazil.

other common names

French: Mérulaxe des bambous; German: Trugzaunkönig; Spanish: Gallito Overo.

physical characteristics

5.3 in (13.5 cm); 0.39–0.46 oz (11–13 g). Tail is fairly long, graduated. Male is gray above and dotted white. Rump rufous. Tail is brown, barred buff and tipped white. Throat and breast

are white, belly is buff, all underparts are dotted black. Female is similar, but gray above replaced by brown and white below by buff.

distribution

Southeast Brazil and adjacent northeast Argentina.

habitat

Viny bamboo thickets in humid forest.

behavior

Alone or in pairs. Within dense vegetation, occasionally on the ground.

feeding ecology and diet

Hops tirelessly through the branches a few meters above the ground. Feeds on insects and caterpillars.

reproductive biology

Unknown.

conservation status

Near Threatened.

significance to humans

None known.

Ochre-flanked tapaculo

Eugralla paradoxa

taxonomy

Troglodytes paradoxus Kittlitz, 1830, Concepción, Chile.

other common names

French: Mérulaxe à flancs ocre; German: Rostflanken-Tapaculo; Spanish: Churrín de la Mocha.

physical characteristics

5.7 in (14.5 cm); 0.92–1.02 oz (26–29 g). Bill elevated at base. Dark gray, rump and flanks rufous. Legs bright yellow.

distribution

Chile from Santiago to Chiloé and adjacent Argentina in Río Negro.

habitat

Undergrowth of humid Nothophagus forest, mainly bamboo thickets.

behavior

Moves in close pairs.

feeding ecology and diet

Forages near or on the ground within dense thickets, sometimes digging with both feet simultaneously in an awkward jump.

reproductive biology

Nest is bulky and globular with a side entrance, placed hidden 3–6 ft (1–2 m) above ground, occasionally higher. Two, rarely three eggs. Both parents tend the nestlings.

conservation status

Not threatened.

significance to humans

None known.

Ocellated tapaculo

Acropternis orthonyx

taxonomy

Merulaxis orthonyx Lafresnaye, 1843, Colombia.

other common names

French: Mérulaxe ocellé; German: Perlenmanteltapaculo; Spanish: Churrín Ocelado.

physical characteristics

8.5 in (21.5 cm); 2.9–3.5 oz (81–100 g). Hindclaw very long and straight. Bill elevated at base. Mainly black with large white spots. Rump and flanks chestnut. Forehead, face, throat and upper breast rufous.

distribution

A. o. orthonyx: Andes of northwest Venezuela, and eastern and central chains of Colombia. A. o. infuscata: Andes of Ecuador and northern Peru.

habitat

Mainly bamboo thickets in humid forest.

behavior

Almost invariably in close pairs rummaging slowly on the forest floor or hopping lethargically through tangles of bamboo, occasionally onto mossy trunks and thick branches several meters above the ground.

feeding ecology and diet

Digs with both feet simultaneously in an awkward jump. Food includes both arthropods and plant material.

reproductive biology

Unknown.

conservation status

Not threatened.

significance to humans

None known. A single individual in New York Zoo survived a few months in captivity.

Resources

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Niels K. Krabbe, PhD