• Summary
• Text account
• Data table and detailed info
• Distribution map
• Reference and further resources

Taxonomic source(s)
del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A., Fishpool, L.D.C., Boesman, P. and Kirwan, G.M. 2016. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Volume 2: Passerines. Lynx Edicions and BirdLife International, Barcelona, Spain and Cambridge, UK.
SACC. 2005 and updates. A classification of the bird species of South America. Available at: https://www.museum.lsu.edu/~Remsen/SACCBaseline.htm.

Red List criteria met

Critically Endangered	Endangered	Vulnerable
C2a(i,ii); D	B1ab(v)+2ab(v); C2a(i,ii); D	B1ab(v)+2ab(v); C2a(i,ii); D1

Red List history

Year	Category	Criteria
2021	Critically Endangered	C2a(i,ii); D
2019	Critically Endangered	C2a(i,ii); D
2016	Critically Endangered	C2a(i,ii); D
2015	Critically Endangered	C2a(i,ii); D
2012	Critically Endangered	C2a(i);D
2010	Critically Endangered	B1a+b(i,ii,iii,v)
2009	Critically Endangered	B1a+b(i,ii,iii,v)
2008	Critically Endangered
2004	Critically Endangered
2000	Critically Endangered
1996	Critically Endangered
1994	Critically Endangered
1988	Not Recognised

Migratory status	not a migrant	Forest dependency	high
Land-mass type	continent	Average mass	-

	Estimate	Data quality
Extent of Occurrence (breeding/resident)	230 km2	medium
Area of Occupancy (breeding/resident)	230 km2
Number of locations	5-10	-
Severely fragmented?	no	-

	Estimate	Data quality	Derivation	Year of estimate
Population size	1-49 mature individuals	medium	estimated	2020
Population trend	decreasing	poor	inferred	-
Generation length	2.76 years	-	-	-
Number of subpopulations	1	-	-	-
Percentage of mature individuals in largest subpopulation	100%	-	-	-

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).

Country/Territory	Presence	Origin	Resident	Breeding visitor	Non-breeding visitor	Passage migrant
Brazil	extant	native	yes

Country/Territory	IBA Name
Brazil	Mata do Estado (Mata do Sirigi)
Brazil	Murici

Habitat (level 1)	Habitat (level 2)	Importance	Occurrence
Forest	Subtropical/Tropical Moist Lowland	major	resident
Altitude	430 - 790 m	Occasional altitudinal limits

Threat (level 1)	Threat (level 2)	Impact and Stresses
Agriculture & aquaculture	Annual & perennial non-timber crops - Agro-industry farming	Timing		Scope		Severity		Impact
		Past, Likely to Return		Majority (50-90%)		Slow, Significant Declines		Past Impact
		Stresses Ecosystem degradation, Ecosystem conversion
Agriculture & aquaculture	Annual & perennial non-timber crops - Small-holder farming	Timing		Scope		Severity		Impact
		Past, Likely to Return		Minority (<50%)		Slow, Significant Declines		Past Impact
		Stresses Ecosystem degradation, Ecosystem conversion
Agriculture & aquaculture	Livestock farming & ranching - Agro-industry grazing, ranching or farming	Timing		Scope		Severity		Impact
		Past, Likely to Return		Majority (50-90%)		Slow, Significant Declines		Past Impact
		Stresses Ecosystem degradation, Ecosystem conversion
Biological resource use	Hunting & trapping terrestrial animals - Unintentional effects (species is not the target)	Timing		Scope		Severity		Impact
		Past, Likely to Return		Whole (>90%)		Negligible declines		Past Impact
		Stresses Species disturbance
Biological resource use	Logging & wood harvesting - Unintentional effects: (subsistence/small scale) [harvest]	Timing		Scope		Severity		Impact
		Past, Likely to Return		Whole (>90%)		Slow, Significant Declines		Past Impact
		Stresses Species disturbance, Ecosystem degradation
Climate change & severe weather	Habitat shifting & alteration	Timing		Scope		Severity		Impact
		Future		Whole (>90%)		Unknown		Unknown
		Stresses Indirect ecosystem effects, Ecosystem degradation

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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.