• 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
-	-	-

Red List history

Year	Category	Criteria
2023	Least Concern
2016	Near Threatened	A2c+3c+4c;C1+2a(i)
2012	Near Threatened	A2c+3c+4c;C1+2a(i)
2008	Near Threatened	A2c; A3c; A4c; C1; C2a(i)
2004	Near Threatened
2000	Vulnerable
1996	Vulnerable
1994	Vulnerable
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)	254,000 km2	medium
Severely fragmented?	no	-

	Estimate	Data quality	Derivation	Year of estimate
Population size	unknown	-	-	-
Population trend	decreasing	poor	suspected	2016-2026
Rate of change over the past 10 years/3 generations (longer of the two periods)	1-9%	-	-	-
Rate of change over the future 10 years/3 generations (longer of the two periods)	1-9%	-	-	-
Rate of change over the past & future 10 years/3 generations (longer of the two periods)	1-9%	-	-	-
Generation length	2.85 years	-	-	-
Number of subpopulations	2-100	-	-	-
Percentage of mature individuals in largest subpopulation	1-89%	-	-	-

Population justification: The population size has not been quantified, but the species is commonly observed across its range (eBird 2022). The population is suspected to exceed 10,000 mature individuals, but may potentially be substantially larger.

Trend justification: Although data on population trends are lacking, slow declines are suspected on the basis of ongoing habitat loss and degradation.
Within the range, 3% of tree cover is lost over ten years (Global Forest Watch 2021, using Hansen et al. [2013] data and methods disclosed therein). The species shows some tolerance of secondary and open forests (Zimmer and Isler 2020), and population declines are therefore likely equally low and localised; they are here tentatively placed in the band 1-9% over ten years.

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

Country/Territory	IBA Name
Brazil	Estação Ecológica de Juréia-Itatins
Brazil	Parque Estadual da Serra do Mar (entre Caraguatatuba e Picinguaba)
Brazil	Parque Estadual da Serra do Mar (entre Pedro de Toledo e Cubatão)
Brazil	Parque Estadual da Serra do Mar (entre Santos e São Sebastião)
Brazil	Reserva Biológica de Poço das Antas

Habitat (level 1)	Habitat (level 2)	Importance	Occurrence
Artificial/Terrestrial	Subtropical/Tropical Heavily Degraded Former Forest	suitable	resident
Forest	Subtropical/Tropical Dry	major	resident
Forest	Subtropical/Tropical Moist Lowland	suitable	resident
Savanna	Dry	suitable	resident
Altitude	0 - 1230 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
		Ongoing		Minority (<50%)		Slow, Significant Declines		Low Impact: 5
		Stresses Ecosystem degradation, Ecosystem conversion
Agriculture & aquaculture	Annual & perennial non-timber crops - Small-holder farming	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Slow, Significant Declines		Low Impact: 5
		Stresses Ecosystem degradation, Ecosystem conversion
Biological resource use	Logging & wood harvesting - Unintentional effects: (large scale) [harvest]	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Slow, Significant Declines		Low Impact: 5
		Stresses Ecosystem degradation, Ecosystem conversion
Biological resource use	Logging & wood harvesting - Unintentional effects: (subsistence/small scale) [harvest]	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Slow, Significant Declines		Low Impact: 5
		Stresses Ecosystem degradation, Ecosystem conversion
Residential & commercial development	Housing & urban areas	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Slow, Significant Declines		Low Impact: 5
		Stresses Ecosystem degradation, Ecosystem conversion

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Recommended citation
BirdLife International (2024) Species factsheet: Unicolored Antwren Myrmotherula unicolor. Downloaded from https://datazone.birdlife.org/species/factsheet/unicolored-antwren-myrmotherula-unicolor 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.