VU
Pectoral Antwren Herpsilochmus pectoralis



Justification

Justification of Red List Category
The widespread destruction of suitable deciduous forest has reduced this species's now small population and (poorly understood) range (Collar et al. 1992). Remaining populations are severely fragmented and the species qualifies as Vulnerable.

Population justification
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. Densities of 60-113 birds/km2 have been found (Silva 2007).

Trend justification
Forest loss within the species's range has been estimated at c.3.4% over 3 generations (c.14 years) (Tracewski et al. 2016). Therefore, the rate of decline in this species is suspected to be <10% over 3 generations.

Distribution and population

Herpsilochmus pectoralis possesses an unusual and highly fragmented range in north-east Maranhão (most recently, Axixá in the 1980s, Bacabal in 1974 [E. O. Willis in litt 1999] and Fazenda do Caimbo in 1972), east Rio Grande do Norte (23 sites in 12 municipalities in 2005-2007 [Silva 2007]), Sergipe (Itabaiana in 1991), Paraiba (first state record in Guaju in 2004 [Perreira et al. 2005]) and north-east Bahia (eight localities, five with records since 1980 [J. M. C. da Silva in litt. 1995, G. M. Kirwan in litt. 1999, A. Whittaker in litt. 1999]), north-east Brazil. It is clearly extremely local and is considered to have disappeared from a large part of its former range (B. Whitney in litt. 2017). However, although overall numbers are presumably not high, it is fairly common at some sites in Bahia. Tracewski et al. (2016) estimated the maximum Area of Occupancy (calculated as the remaining tree area within the species’s range) to be c.1,850 km2, rounded here to 1,900 km2.

Ecology

It inhabits gallery forest and deciduous forest in Maranhão, and tall caatinga woodland and closed, old secondary forest in Bahia. It survives in remnant woodlots characterised by numerous trees over 10 m, and often 15-20 m, but is not found in adjacent habitats with smaller trees. Some of these woodlots are moderately grazed, but it only occurs where there is still a fairly well developed understorey.

Threats

It is still insufficiently known to determine precise threats, but clearance for irrigated and dry field agriculture has removed extensive tracts of deciduous forest (da Silva and Oren 1997). The high biomass of these forests makes them important sources of charcoal for Brazil's steel and pig-iron industries, and supposedly substitute plantations of Eucalyptus sp. are being used by the paper pulp industry (da Silva and Oren 1997). Intensive grazing and extensive burning are widespread throughout its range.

Conservation actions

Conservation Actions Underway
It is protected under Brazilian law and occurs in Serra de Itabaiana Ecological Station, Sergipe, and Chapada da Diamantina National Park, Bahia (Wege and Long 1995). Logging trucks were observed extracting timber from the latter in February 1996 (A. Whittaker in litt. 1999), indicating that protection is inadequate.

Conservation Actions Proposed
Survey to improve knowledge of its distribution and habitat requirements. Survey Serra de Itabaiana for this and other threatened species. Map and ecologically evaluate extant patches of deciduous forest (da Silva and Oren 1997), especially in Bahia. Conduct long-term studies on the ecology of this species's forests (e.g. succession and selective logging) to develop viable strategies for economic utilisation (da Silva and Oren 1997). Create a system of conservation units (following surveys and mapping) that adequately protects the species, including the site 23 km from Jeremoaba in Bahia, an area in central Maranhão and the de facto protection and expansion of Chapada da Diamantina National Park to include known sites just outside the park's boundaries.

Identification

11.5 cm. Long-tailed, well-marked antwren. Male has black crown, white supercilium and black postocular eye-stripe. Grey nape and mantle with black-and-white streaking on latter. Black wings with large white covert tips forming two wing-bars. White spotting on shoulders and fringing to flight feathers. Black tail, boldly tipped white. White underparts with black pectoral crescent. Female has olive upperparts with rufous crown. White tips to uppertail-coverts. Uniform dull buff underparts, brightest on breast. Voice Song is fast ascending series of 14-20 notes, levelling off on the last 4-5, in 2-3 seconds. Female song similar but shorter. Also short, barking call.

Acknowledgements

Text account compilers
Capper, D., Westrip, J., Pople, R., Symes, A., Wheatley, H., Sharpe, C.J.

Contributors
Whittaker, A., Kirwan, G., da Silva, J., Willis, E., Whitney, B.


Recommended citation
BirdLife International (2019) Species factsheet: Herpsilochmus pectoralis. Downloaded from http://www.birdlife.org on 25/05/2019. Recommended citation for factsheets for more than one species: BirdLife International (2019) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 25/05/2019.