Stresemann's Bristlefront Merulaxis stresemanni


Justification of Red List Category
This species remained unrecorded for 50 years until it was rediscovered in 1995 near Una, Bahia, but there have been no more records from this locality despite subsequent searches. However, it has now also been found in Bandeira county, in the border of the Pardo and Jequitinhonha valleys, Minas Gerais and Bahia, where its extremely small range and population, at a single location, is declining owing to fires, logging and the clearance of steep humid valley-floor forest for cattle-ranching and agriculture. The entire population may now number just 10-15 individuals. For these reasons it is classified as Critically Endangered.

Population justification
In the Jequitinhonha valley (the sole currently known population), at least four birds were found in a 100 ha area, but it was thought unlikely that this density could be extrapolated for the whole 5,000 ha partly fragmented patch of forest (R. Ribon in litt. 2006). Surveys of the Macarani / Bandeira area near Balbina (Sossego do Arrebol Forest) found just six individuals: five females and a single male (Fundação Biodiversitas in litt. 2010). Three males were recorded in 2012 (WikiAves 2013) but there are likely no more than 10-15 birds in total and none have been found in other forest fragments surveyed (R. Ribon in litt. 2011). It is therefore now suspected that there may be fewer than 50 birds remaining, and the population is placed in the band 1-49 mature individuals.

Trend justification
The species is suspected to be in decline based on rates of habitat loss and degradation.

Distribution and population

Merulaxis stresemanni was known until relatively recently from just two specimens, the type, collected near Salvador in the 1830s, and a second taken near Ilhéus in 1945, in coastal Bahia, Brazil. In 1995, it was rediscovered in the wild when a male was observed and tape-recorded at Fazenda Jueirana, near Una Biological Reserve, Bahia (Baudet 2001). Subsequent searches there have failed to produce further records (Baudet 2001, F. Olmos in litt. 2003). However, the species was subsequently found in the Jequitinhonha valley, Minas Gerais, near the border with Bahia (Ribon et al. 2004). Here, too, the future of the species seems to hang in the balance: it lives in a strip of humid valley-floor forest, much of which has recently been cleared to make room for agriculture (F. Olmos in litt. 2006) and pasture (R. Ribon in litt 2007).


Very little is known, but its behaviour and habitat preferences appear similar to those of M. ater (Baudet 2001). The male in 1995 was observed foraging on the ground and on fallen tree trunks in an area of drier forest between two humid valleys (Baudet 2001). The species is found in the understorey of mature humid forest, often comprised of Cecropia spp., at 600-930 metres along the Jequitinonha and Pardo River valleys (R. Ribon in litt 2007, Damasceno 2011). The species has been observed apparently feeding on insects on dry litter and under fallen logs (Fundação Biodiversitas in litt. 2010). Birds are very responsive to play-back, approaching the observer to 2 m (R. Ribon in litt 2007), and move mainly by walking or short-distance flights (Damasceno 2011). The average territory size of three birds was 2.36 ha, based on initial studies, but more data are required (Fundação Biodiversitas in litt. 2010). The first known nest site was found in 2012, and consisted of a tennis-ball sized hole c.3 feet above the ground in an exposed dirt bank with overhanging vegetation, with a nesting tunnel estimated to be c.6 feet deep (ABC 2013).


Most humid forest in Bahia has been cleared or converted to cacao plantations, and remaining patches are disappearing very rapidly. Forest in the Minas Gerais and Bahia border area is being cleared for small (mostly in Jordânia county, Minas Gerais) and large scale cattle ranching (R. Ribon in litt 2007). Forest is also degraded by loggers from Bahia state (R. Ribon in litt 2007). Intentional or accidental fires are set every year, degrading the border of the remaining pristine forest (R. Ribon in litt 2007).

Conservation actions

Conservation Actions Underway
It is considered Critically Endangered at the national level in Brazil (MMA 2014), and protected by Brazilian law. The sighting in 1995 was in a privately-owned fazenda adjacent to the 5,400 ha Una Biological Reserve. A reforestation project aiming to create a biological corridor between Una and Serra das Lontras is planned (F. Olmos in litt. 2003). Ten percent of the forest tract where the species was discovered in Macarani County in 2005 (the 400 ha Mata da Balbina in Jequitinhonha valley, Bandeira and Macarani municipalities) was purchased by the Fundação Biodiversitas, a local NGO from Minas Gerais, with funds from the American Bird Conservancy, and is managed as Reserva do Passarinho, a Private Natural Heritage Reserve (P. Develey in litt. 2007, Anon 2008, Whitehouse and Ribon 2010). Within an initial three-year period targets were to create an initial infrastructure, investigate the conservation status of M. stresemanni, and enhance the institutional presence in the area (Anon 2008). A further 194 ha section of forest was purchased in March 2009, along with infrastructure improvement and the hiring of a reserve manager (American Bird Conservancy 2009, SAVE Brasil in litt. 2010). All the remaining forest (c.4,300 ha) is virtually unprotected and needs urgent protection (R. Ribon in litt 2007). Surveys are being carried out to assess the population size of the species (Fundação Biodiversitas in litt. 2010, SAVE Brasil in litt. 2010).

Conservation Actions Proposed
Carry out surveys including playback in Jequitinhonha, Bandeira and and Fazenda Jueirana to determine the size and status of this population. Search for additional populations in all fragments of lowland forests in Bahia and Minas Gerais, using the voice cut now available, and determine the size and status of the remaining population. Safeguard the remaining unprotected 4,300 hectares of forest in the Jequitinhonha valley, and all remaining tracts of humid forest in Bahia. Create corridors to connect small tracts of pristine forest currently disconnected from the largest tract on the Bandeira-Jordânia-Macarani border. Regulate use of playback on tiny known population, whilst maintaining potential for ecotourism.


20 cm. Medium-sized, long-tailed bird with distinctive forehead bristles. Male all slaty-plumbeous. Dark rufous-chestnut rump, uppertail-coverts and vent, although rump and uppertail coverts appear more greyish than vent, which is more rufescent. Long, pointed bristles on forehead. Slender dark bill. Female is cinnamon-brown above, with duskier tail. Bright cinnamon-rufous below. Similar spp. Very similar to Slaty Bristlefront M. ater but no known overlap in range. (one specimen of M. ater purported to be obtained Bahia by Helmut Sick is probably M. stresemanni) Voice Very different from M. ater. Characteristic falling series of musical whistled notes, slightly ascending in the end, of 10-12 seconds duration. Also semi-musical tink call.


Text account compilers
Sharpe, C.J., Symes, A., Taylor, J., Capper, D., Clay, R.P., Bird, J., Calvert, R., Hermes, C., Butchart, S., Mahood, S., Pople, R.

Ribon, R., Olmos, F., Develey, P.

Recommended citation
BirdLife International (2021) Species factsheet: Merulaxis stresemanni. Downloaded from on 16/10/2021. Recommended citation for factsheets for more than one species: BirdLife International (2021) IUCN Red List for birds. Downloaded from on 16/10/2021.