Biatas nigropectus 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Aves Passeriformes Thamnophilidae

Scientific Name: Biatas nigropectus (Lafresnaye, 1850)
Common Name(s):
English White-bearded Antshrike
Taxonomic Source(s): SACC. 2005 and updates. A classification of the bird species of South America. Available at: #
Identification information: 18 cm. Brown-and-black antshrike. Overall rich brown with rufous wings and tail, olivaceous-buff below. Male has black cap, which is often raised. White ear-coverts and chin join pale buff nuchal collar. Whitish supercilium sometimes hidden. Black lower throat and breast. Considerable variation between individuals in extent of black bib, and colour of bill (ivory to silver) and legs (grey to light blue); individuals with different colouration exist at the same sites and variation does not appear to be geographically based. Female has rufous crown, whitish supercilium and olive-brown breast. Similar spp. Female similar to White-collared Foliage-gleaner Anabazenops fuscus, which lacks rufous crown and wings, and has different bill shape and behaviour. Voice Series of 6-12 soft, fluty kíu notes (c.2 per second).

Assessment Information [top]

Red List Category & Criteria: Vulnerable A2c+3c+4c;B1ab(i,ii,iii,iv,v)c(iv);C2a(i)b ver 3.1
Year Published: 2017
Date Assessed: 2016-10-01
Assessor(s): BirdLife International
Reviewer(s): Butchart, S. & Symes, A.
Contributor(s): Bodrati, A., Cockle, K. & De Luca, A.
Facilitator/Compiler(s): Capper, D., Pople, R., Sharpe, C.J., Symes, A., Williams, R., Khwaja, N.
A total dependence on one or few species of bamboo whose reproduction is followed by massive die-off events, coupled with a substantial reduction in suitable habitat, suggests that this species's current population is small, fragmented and rapidly declining. It consequently qualifies as Vulnerable.

Previously published Red List assessments:

Geographic Range [top]

Range Description:Biatas nigropectus is rare in south-east Brazil and uncommon in north-east Argentina. All Argentine records are from Misiones, where the largest series of specimens has been obtained. The species persists in stands of Guadua trinii bamboo throughout northern and eastern Misiones from Iguazú National Park to the Yabotí Biosphere Reserve, and especially in the area from the northern half of the Yabotí Biosphere Reserve to Santa Rosa and Piñalito Sur (Bodrati and Cockle 2006, A. Bodrati in litt. 2007). Between 2003 and 2011, more than 300 individuals have been detected in Misiones using tape playback (Bodrati and Cockle 2006, A. Bodrati in litt. 2007, A. Bodrati and K. Cockle in litt. 2012). In Brazil, most records are from Rio de Janeiro and São Paulo, with Itatiaia National Park and Intervales State Park particular strongholds. There are further records from Minas Gerais, from Itatiaia on the border with Rio de Janeiro, and at Itabira and São Domingos do Prata in the mid-1980s; Paraná, from Iguaçu National Park, Fazenda Santa Rita and the Tibagi River Basin (Anjos et al. 1997), and Santa Catarina, from Araranguá (do Rosário 1996) and Serra do Itajaí National Park (Kohler et al. 2009). Evidence from the 19th century indicates that this was always a rare bird, but it is presumably declining in response to habitat loss.

Countries occurrence:
Argentina; Brazil
Additional data:
Continuing decline in area of occupancy (AOO):Yes
Extreme fluctuations in area of occupancy (AOO):NoEstimated extent of occurrence (EOO) - km2:605000
Continuing decline in extent of occurrence (EOO):YesExtreme fluctuations in extent of occurrence (EOO):No
Number of Locations:11-100Continuing decline in number of locations:Yes
Extreme fluctuations in the number of locations:No
Upper elevation limit (metres):1200
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:The population is estimated to number 2,500-9,999 mature individuals based on an assessment of known records, descriptions of abundance and range size. This is consistent with recorded population density estimates for congeners or close relatives with a similar body size, and the fact that only a proportion of the estimated Extent of Occurrence is likely to be occupied. This estimate is equivalent to 3,750-14,999 individuals, rounded here to 3,500-15,000 individuals.

Trend Justification:  This species's population is suspected to be declining rapidly, in line with rates of habitat loss within its range.
Current Population Trend:Decreasing
Additional data:
Number of mature individuals:2500-9999Continuing decline of mature individuals:Yes
Extreme fluctuations:YesPopulation severely fragmented:Yes
No. of subpopulations:2-100Continuing decline in subpopulations:Yes
Extreme fluctuations in subpopulations:NoAll individuals in one subpopulation:No

Habitat and Ecology [top]

Habitat and Ecology:It inhabits stands of bamboo in lowland and montane Atlantic forest up to 1,200 m, occurring primarily in openings and along edges where thickets are most extensive and tall. In Argentina, it is an extreme habitat specialist, found only in stands of Guadua bamboo, with nearly all records in Guadua trinii (Bodrati and Cockle 2006, A. Bodrati in litt. 2007). In Argentina, it inhabits stands of Guadua trinii bamboo even on small-holder farms where all other forest vegetation has been removed (A. Bodrati in litt. 2007). The diet includes insect larvae, spiders, small ants and seeds (Bodrati et al. 2005). Breeding is probably between October and January. It is usually very hard to observe, individuals being hidden among foliage in the bamboo canopy and rarely vocalising spontaneously (Bodrati and Cockle 2006, A. Bodrati in litt. 2007).

Continuing decline in area, extent and/or quality of habitat:Yes
Generation Length (years):4.8
Movement patterns:Not a Migrant

Threats [top]

Major Threat(s): In Brazil, there has been rapid destruction and fragmentation of Atlantic forest for agriculture, mining, and coffee, banana and rubber plantations (Fearnside 1996). Remaining forest in Brazil suffers from urbanisation, associated road-building and agricultural expansion (Dinerstein et al. 1995). In Argentina, the species depends on Guadua trinii bamboo (Bodrati and Cockle 2006), which has a 30 year cycle of growth, mast seeding, and massive die-off (Parodi 1955). It is not known how Biatas nigropectus responds to these bamboo cycles, but strong population fluctuations are suspected, with bottlenecks during periods of bamboo die-off, increasing the species's vulnerability to stochastic extinction (A. Bodrati in litt. 2007). It is a species that could easily "fall through the cracks" of current conservation policies, because its bamboo habitat is rarely contemplated in conservation strategies for the Atlantic forest. In Misiones, most Guadua trinii, and hence most records of Biatas nigropectus, are outside of parks, often near houses, plantations and roads, where the bamboo has colonised degraded forest and is at considerable risk of being cleared (A. Bodrati in litt. 2007, A. Bodrati and K. Cockle in litt. 2012).

Conservation Actions [top]

Conservation Actions: Conservation Actions Underway
It occurs in a number of protected areas: Itatiaia, Serra dos Órgãos, Serra do Itajaí (Kohler et al. 2009) and Iguaçu national parks, Juréia-Itatins Ecological Station (Develey 1997), Intervales, Serro do Mar and Desengano state parks, all in Brazil, and Yabotí Biosphere Reserve (A. Bodrati in litt. 2007), Iguazú National Park, and Cruce Caballero, Piñalito, and Urugua-í provincial parks, in Argentina (Wege and Long 1995, Bodrati and Cockle 2006). Proyecto Selva de Pino Paraná is raising local awareness of this species and its dependence on Guadua trinii around San Pedro and Tobuna, Misiones. Formerly considered Vulnerable at the national level (Silveira & Straube 2008), it is no longer considered threatened in Brazil (MMA 2014).

Conservation Actions Proposed
Survey to estimate population densities and clearly delineate the distribution of this species using tape-playback. Study its dependence on Guadua bamboo, particularly in Brazil where other genera are reportedly used (A. Bodrati and K. Cockle in litt. 2012). Determine its response to massive bamboo die-off events, to advise the creation of networks of protected areas capable of sustaining the species through full cycles of bamboo growth and die-off. Determine the minimum size of bamboo stands needed to support a territory. Study the ecology and life cycle of Guadua bamboos. Assess the distribution of its bamboo habitat. Target populations of Biatas nigropectus when creating or enlarging protected areas in Argentina, e.g. Cruce Caballero Provincial Park (Bodrati and Cockle 2006). Protect key areas in Santa Catarina and Paraná. In Misiones, raise local awareness and provide technical support to promote soil conservation on small-holder farms, especially around parks, to avoid clearing of Guadua bamboo for crops. Conservation strategies for the Atlantic forest should include measures to conserve the complex spatio-temporal dynamics of bamboo stands and their inhabitants (A. Bodrati and K. Cockle in litt. 2012).

Amended [top]

Amended reason: Map revised.

Citation: BirdLife International. 2017. Biatas nigropectus (amended version of 2016 assessment). The IUCN Red List of Threatened Species 2017: e.T22701272A110784314. . Downloaded on 18 June 2018.
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