• 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
2024	Least Concern
2016	Vulnerable	A3c
2012	Vulnerable	A3c
2009	Least Concern
2008	Least Concern
2004	Least Concern
2000	Lower Risk/Least Concern
1994	Lower Risk/Least Concern
1988	Lower Risk/Least Concern

Migratory status	not a migrant	Forest dependency	high
Land-mass type		Average mass	12 g

	Estimate	Data quality
Extent of Occurrence (breeding/resident)	727,000 km2	medium
Severely fragmented?	no	-

	Estimate	Data quality	Derivation	Year of estimate
Population size	unknown	-	-	-
Population trend	decreasing	-	suspected	2017-2027
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	3 years	-	-	-
Number of subpopulations	11-100	-	-	-
Percentage of mature individuals in largest subpopulation	1-89%	-	-	-

Population justification: The global population size has not been quantified, but this species is generally described as uncommon or rare (Stotz et al. 1996, Herzog et al. 2016, Freile and Restall 2018). It is however easily overlooked (Schulenberg 2020) and may therefore be more numerous and widespread than assumed.

Trend justification: The only threat known to the species is the logging and fragmentation of forests within the range. On the basis of ongoing habitat loss, population declines are suspected.
The population trend has not been quantified. Tree cover within the range is lost at a rate of 5% over ten years (Global Forest Watch 2023, using Hansen et al. [2013] data and methods disclosed therein). Even though the species depends on forests, its preference for edge habitat suggests some tolerance of forest loss. Population declines are therefore likely slow; 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
Bolivia	extant	native	yes
Ecuador	extant	native	yes
Peru	extant	native	yes

Country/Territory	IBA Name
Ecuador	Cordillera del Cóndor
Ecuador	Parque Nacional Sumaco-Napo Galeras
Peru	Cordillera de Colán
Peru	Manu
Peru	Parque Nacional Cordillera Azul

Habitat (level 1)	Habitat (level 2)	Importance	Occurrence
Artificial/Terrestrial	Subtropical/Tropical Heavily Degraded Former Forest	suitable	resident
Forest	Subtropical/Tropical Moist Lowland	major	resident
Forest	Subtropical/Tropical Moist Montane	suitable	resident
Altitude	750 - 1780 m	Occasional altitudinal limits

Threat (level 1)	Threat (level 2)	Impact and Stresses
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
Agriculture & aquaculture	Livestock farming & ranching - Small-holder grazing, ranching or 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: (subsistence/small scale) [harvest]	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Slow, Significant Declines		Low Impact: 5
		Stresses Ecosystem degradation, Ecosystem conversion
Energy production & mining	Mining & quarrying	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Slow, Significant Declines		Low Impact: 5
		Stresses Ecosystem degradation, Ecosystem conversion
Transportation & service corridors	Roads & railroads	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Negligible declines		Low Impact: 4
		Stresses Ecosystem degradation, Ecosystem conversion

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Recommended citation
BirdLife International (2024) Species factsheet: Red-billed Tyrannulet Zimmerius cinereicapilla. Downloaded from https://datazone.birdlife.org/species/factsheet/red-billed-tyrannulet-zimmerius-cinereicapilla on 23/12/2024.
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 23/12/2024.