Data Zone
Justification of Red List category
This species is listed as Critically Endangered because it is likely to have an extremely small population that is restricted to a single subpopulation and is inferred to be declining, possibly due to the loss of ecological processes resulting from past habitat loss.
Population justification
It is likely that fewer than 30 individuals persist (Pereira et al. 2014). Consistent with this estimate, during intensive fieldwork at Murici between 2018 and 2020, 17 individuals were recorded (H. Vilela in prep, in B. Phalan in litt. 2020). The population size is therefore placed in the band 1-49 mature individuals. The lack of recent records outside Murici suggests that the population outside this site may have disappeared (B. Phalan in litt. 2018), so there is now likely to be only one subpopulation.
Trend justification
This species is inferred to be declining from the apparent reduction in numbers recorded during recent fieldwork (Vilela 2017, H. Vilela in prep.), and from anecdotal evidence of increased difficulty in finding the species (B. Phalan in litt. 2020).
The species is reported to have been common at Murici in 1979 (D. Teixeira, per H. Vilela in litt. 2020). That is no longer the case, and anecdotal evidence indicates that the species has become increasingly difficult to find at Murici in recent years (C. Albano, per B. Phalan in litt. 2020). This is supported by more recent fieldwork and systematic surveys. The lack of recent records outside Murici suggests that the population outside this site has declined, if not disappeared (B. Phalan in litt. 2018).
During 42 expeditions to Murici between 2010 and 2017, a total of 17 individuals were captured in mist nets and marked with metal and colour rings (H. Vilela in litt. 2020). During 38 days in the field at Murici from 2016 to 2017, active searches with playback were used, resulting in 22 individuals located at 12 locations. Only three of these individuals were observed to have rings. Searches were carried out opportunistically along the network of pre-existing trails and effort was not systematic (Vilela 2017). Monthly visits to all 28 known or potential territories at Murici from October 2018 to May 2019, using ten-minute point counts with playback over 74 days in the field, resulted in records of 12 individuals in total, at seven of the surveyed locations (H. Vilela in prep.). These surveys added one additional occupied location to the territories located during 2016-2017, and just one ringed bird was seen. During monthly visits from October 2019 to January 2020 to the same 28 locations, over 56 days in the field, 11 individuals were found at six sites. Five of those individuals were different to those observed in 2018-2019, and thus a total of 17 birds were recorded in the period 2018 to 2020. Taken together, these data from three field seasons may indicate an ongoing decline at Murici, but it is possible that methodological differences explain the decline in numbers from 2016-2017 to more recent years (H. Vilela in litt. 2020).
The number of subpopulations is likely to have declined from four to one between 1999 and 2020 (B. Phalan in litt. 2020).
Myrmotherula snowi has only been recorded in Alagoas and Pernambuco states, north-east Brazil. It was first discovered at Murici (Alagoas) in 1979, when an adult male and two adult females were collected (Teixeira and Gonzaga 1985). An additional juvenile male was collected in 1984, and subsequent records throughout the 1990s, in 2000 and in 2009 have only found the species in very small numbers (Whitney and Pacheco 1995, 1997, J. M. Goerck in litt. 1999, A. Whittaker in litt. 1999, J. M. Goerck in litt. 2000, F. Olmos in litt. 2002). The species has also been recorded in Pernambuco at Mata do Estado (in São Vicente Férrer municipality) in 1999 (F. Olmos in litt. 2002, Roda et al. 2003), Frei Caneca (in Jaqueira municipality) in 2003 and 2007 (Mazar Barnett et al. 2005, Albano 2007) and Mata do Benedito, Engenho Jussará (in Gravatá municipality) in 2005 and 2006 (Albano 2006, S. Roda in litt. 2007, Roda et al. 2009). Since 2007, the species has not been recorded outside Murici Ecological Station, despite all other known sites having been revisited, and it is likely that the species now only persists at Murici (B. Phalan in litt. 2018).
It forages in pairs and small mixed-species flocks in the middle strata of upland semi-humid forest at 430-790 m (Roda et al. 2011, H. Vilela in litt. 2020). At Murici, it has been observed in mixed flocks with White-flanked Antwren (Myrmotherula axillaris), White-bellied Tody-tyrant (Hemitriccus griseipectus) and occasionally Plain Antvireo (Dysithamnus mentalis), Plain Xenops (Xenops genibarbis) and Northern Rufous-winged Antwren (Herpsilochmus scapularis). However, these associations rarely persisted for more than ten minutes (B. Phalan in litt. 2020). Birds range from 1.5 to 9 m above ground, keeping mostly at 5-8 m (Whitney and Pacheco 1997). The diet consists of arthropods, including spiders, beetles, ants and cockroaches. Breeding occurs from November (possibly as early as September) to February (B. Phalan in litt. 2020). A nest with eggs was found in November 2019 (R. Oliveira, M. Efe, in litt. 2020). A male and female with well-developed gonads, and a female with partially-formed egg, were collected in February, and a male observed with nest material during same month (Teixeira and Gonzaga 1985). Adults with dependent young were observed in March 2019 (H. Vilela, A. Andrade, in litt. 2020) and May (Teixeira and Gonzaga 1985). The nest is an open cup of rhizomorphs of Marasmius fungi, with few or no dead leaves, suspended by the rim in the horizontal fork of a small sapling, 0.9 to 1.9 m above ground (H. Vilela, A. Andrade, M. Efe, R. Oliveira, B. Phalan, in litt. 2020).
Forest at Murici has been reduced from 70 km2 in the 1970s to 30 km2 of highly disturbed and fragmented habitat in 1999 (J. M. Goerck in litt. 1999, 2000), largely as a result of logging and conversion to pasture and sugarcane plantations. The site continues to be threatened by fires spreading from adjacent plantations, hunting, timber extraction and agriculture (J. M. Goerck in litt. 1999, A. Whittaker in litt. 1999, J. M. Goerck in litt. 2000, SAVE Brasil 2016). However, hunting and other illegal activities within the Ecological Station have been largely brought under control during recent years by ICMBio staff, with the last known instance of timber extraction in 2017 (B. Phalan in litt. 2020). This improved regulation of activities might be expected to have both positive effects (reduced forest degradation) and negative effects (possible increase in populations of nest predators such as coati and opossums) on Alagoas Antwren (B. Phalan in litt. 2020). The ongoing population decline seen at Murici may reflect the loss of ecological processes resulting from past habitat loss (M. Efe in litt. 2020). The breakdown of species associations may negatively affect the species (H. Vilela in litt. 2020). It has been commonly sighted foraging within mixed flocks (Mazar Barnett et al. 2005, Whitney and Pacheco 1997, Teixeira and Gonzaga 1985). However, key "nuclear" flock-forming species – notably Alagoas Foliage-gleaner (Philydor novaesi), Cinereous Antshrike (Thamnomanes caesius), Red-crowned Ant-tanager (Habia rubica) and perhaps Cryptic Treehunter (Cichlocolaptes mazarbarnetti) – are now rare or extinct in the remaining range of M. snowi (H. Vilela in litt. 2020). Low reproductive success, while typical for tropical forest birds, could also be a problem for the species. Nest losses, mostly to predation, are around 82% for other understorey-nesting species at Murici (A. Andrade, in prep. 2020).
The Frei Caneca private reserve and BirdLife/SAVE Brasil area are no longer suffering from illegal charcoal exploitation, however in Frei Caneca there is still some illegal expansion of banana plantation replacing the native vegetation (B. Phalan in litt. 2020).
The massive clearance of Atlantic forest in Alagoas and Pernambuco has left few other sites likely to support populations of this species. Having a montane distribution that is close to the maximum altitude within its range, this species is also potentially susceptible to climate change (BirdLife International unpubl. data).
Conservation Actions Underway
Considered Critically Endangered at the national level in Brazil (MMA 2014, ICMBio 2018) and included in the National Action Plan for the Conservation of the Birds of the Atlantic Forest (ICMBio 2017).
The efforts of conservationists resulted in the creation of the Murici Ecological Station in 2001, encompassing 6,116 ha. National and international efforts to ensure the effectiveness of this designation are on-going (J. M. Goerck in litt. 1999, 2000), as private land within the Ecological Station continues to be managed as pasture rather than as part of the protected area (B. Phalan in litt. 2020). Frei Caneca is a private reserve protecting c. 6 km2 of forest (Mazar Barnett et al. 2005); an additional 430 ha of adjacent forest have been purchased by Birdlife/SAVE Brazil (P. Develey in litt. 2020).
The species has been monitored by a team from the Laboratory of Bioecology and Conservation of Neotropical Birds at the Federal University of Alagoas (LABECAN/UFAL) at Murici since 2010 (Efe et al. 2018). Research is ongoing into the species's population size, distribution, demographics, threats and ecology (SAVE Brasil 2016). Searches are underway for further populations in Alagoas and Pernambuco (B. Phalan in litt. 2020).
A species action plan was formulated in 2016 (SAVE Brasil 2016). Actions underway include trials of nest exclosures to exclude nest predators, and development of captive breeding methods at Parque das Aves (a Brazilian private zoo) with an ecologically-similar species, Plain Antvireo (Dysithamnus mentalis; SAVE Brasil 2016, ICMBio 2019). The process of compensating private landowners and integrating their land into the Ecological Station has stalled, and may require additional input and resources from non-governmental actors (B. Phalan in litt. 2020). A project has been initiated to restore forest connecting remnant fragments in the Northeast of Brazil (SAVE Brasil 2019) and to engage local landowners on forest maintenance and restoration.
Conservation Actions Proposed
Continue to monitor the population at Murici and conduct surveys to confirm the species's status at other sites where it has been recorded. Continue to survey other remnant patches of upland Atlantic forest in Alagoas, Pernambuco and Paraíba to search for further populations. Monitor habitat loss and degradation within the species's range. Conduct research into the species's ecology, associations with mixed-flocks and breeding biology. Research threats to the species and determine effective conservation strategies.
Ensure the de facto protection and management of Murici Ecological Station and improve enforcement to prevent illegal conversion, fires, logging and hunting. Implement an environmental education programme with surrounding communities. Restore forest in land adjoining existing forest fragments where the species survives (Pereira et al. 2014), by compensating private landowners and integrating their land into the Ecological Station. Secure the long-term protected status and conservation of Mata do Estado, at Murici Ecological Station, and all remaining forest fragments in the original distribution area of the species (P. Develey in litt. 2020). Expand and reconnect forest fragments (B. Phalan in litt. 2020), prioritizing properties adjacent to large forest fragments (P. Develey in litt. 2020). Without substantial forest restoration in its former range, it is unlikely that the population of the species will be able to recover to the point of no longer being threatened with extinction (B. Phalan in litt. 2020). Pending the results of captive management with Plain Antvireo, implement captive breeding to establish an insurance population and for potential reintroduction (Lees et al. 2014, Pereira et al. 2014, SAVE Brasil 2016, ICMBio 2019).
9.5 cm. Small, uniform antwren. Male entirely grey, slightly paler below with inconspicuous small black patch on throat. Female entirely fulvous-brown above, russet tail. Rufous-buff underparts with white throat. Similar spp. Very similar to Unicoloured Antwren M. unicolor, but not sympatric and has shorter tail and longer bill, and female is more rufescent below. Voice Song is series of 3-6 downslurred, clear-whistled syllables. A kleek contact call and nyiih-nyeeh-nyaah alarm call have been described.
Text account compilers
Wheatley, H.
Contributors
Develey, P., Goerck, J.M., Olmos, F., Phalan, B., Roda, S., Whittaker, A., Efe, M., Andrade, A., Vilela, H., Westrip, J.R.S., Sharpe, C.J., Bird, J., Mahood, S., Ashpole, J, Calvert, R., Capper, D., Pople, R., Symes, A. & Taylor, J.
Recommended citation
BirdLife International (2024) Species factsheet: Alagoas Antwren Myrmotherula snowi. Downloaded from
https://datazone.birdlife.org/species/factsheet/alagoas-antwren-myrmotherula-snowi on 22/12/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from
https://datazone.birdlife.org/species/search on 22/12/2024.