• 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
-	A3c; C2a(i)	A2c+3c+4c; B1ab(ii,iii,iv,v)+2ab(ii,iii,iv,v); C2a(i)

Red List history

Year	Category	Criteria
2024	Endangered	A3c; C2a(i)
2016	Critically Endangered	A3c
2012	Critically Endangered	A3c
2008	Endangered	B1a+b(iii,v); B2a+b(iii,v)
2005	Vulnerable
2004	Endangered
2000	Endangered
1996	Vulnerable
1994	Vulnerable
1988	Near Threatened

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

	Estimate	Data quality
Extent of Occurrence (breeding/resident)	12,500 km2	medium
Area of Occupancy (breeding/resident)	1,200 km2	good
Number of locations	6-10	-
Severely fragmented?	no	-

	Estimate	Data quality	Derivation	Year of estimate
Population size	1200-8100 mature individuals	good	estimated	2022
Population trend	decreasing	poor	inferred	2017-2027
Rate of change over the past 10 years/3 generations (longer of the two periods)	30-49%	-	-	-
Rate of change over the future 10 years/3 generations (longer of the two periods)	50-79%	-	-	-
Rate of change over the past & future 10 years/3 generations (longer of the two periods)	30-49%	-	-	-
Generation length	3.11 years	-	-	-
Number of subpopulations	5-10	-	-	-
Percentage of mature individuals in largest subpopulation	1-89%	-	-	-

Population justification: Extensive playback surveys along the rivers in the Guyanese part of the range found a density of 55 mature individuals/km² (South Rupununi Conservation Society 2021). Combining this with existing population estimates made by Vale et al. (2007) in the remainder of the species' range in Brazil (where density [60 mature individuals/km²] and occupancy estimates were broadly similar), a global population of c.1,900-8,100 mature individuals was extrapolated (South Rupununi Conservation Society 2021, B. O'Shea in litt. 2022). However, given the data used for estimating the habitat extent and population size in Brazil are 20 years old, an updated assessment is urgently required (South Rupununi Conservation Society 2021, B. O'Shea in litt. 2024). With the expectation that population will have declined, but uncertainty increased, the lower bound of the estimate is reduced and the population size estimated to lie within a range of 1,200-8,100 mature individuals.
The population may have previously been panmictic, and the species is monotypic, but the loss of habitat has divided the range into at least five separate areas that are believed to exceed regular dispersal distance in the species (GBIF.org 2023). Precautionarily the largest subpopulation is placed in a band of between 240-2,000 mature individuals.

Trend justification: During surveys along rivers in Guyana, the species was absent from large tracts of seemingly suitable habitat where it had been observed previously (Vale et al. 2007, South Rupununi Conservation Society 2021, B. O'Shea in litt. 2022). It has been hypothesised that the population decline is caused by habitat loss as well as fires degrading and fragmenting habitat, leading to increasing isolation between populations (B. O'Shea in litt. 2022).
Over the past ten years, 22% of tree cover has been lost within the range; since 2017 this has been increasing such that the average rate over the past five years is now equivalent to 30% over ten years between 2017 and 2027 (Global Forest Watch 2023, using Hansen et al. [2013] data and methods disclosed therein). These values however do not account for additional habitat degradation and fragmentation. The species may be disproportionately affected due to its strict habitat requirements, as its riverine habitat is easily accessible and thus highly susceptible to forest loss and degradation. To illustrate this, comparable surveys between 2004 and 2021 indicated a range contraction exceeding 50 linear kilometers along the Ireng (Maú) River (B. O'Shea in litt. 2024). Moreover, large parts of the range lie within the footprint of the proposed Bem Querer hydroelectric dam on rio Cotingo (Naka et al. 2020, Aleixo et al. 2023). This is scheduled for completion in 2031 and will flood a significant proportion of the species' habitat, with no prospect for the creation of new suitable areas. Tentatively, rates of population decline are suspected to have been within the band 30-49% over the past ten years, to accelerate but remain within this band in the ten years from 2017 to 2027 and subsequently accelerate to exceed 50% in the ten years from 2025 to 2035.

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

Country/Territory	IBA Name
Brazil	Lavrados de Roraima
Brazil	Savanas do Rio Cotingo

Habitat (level 1)	Habitat (level 2)	Importance	Occurrence
Forest	Subtropical/Tropical Moist Lowland	major	resident
Wetlands (inland)	Permanent Rivers/Streams/Creeks (includes waterfalls)	suitable	resident
Altitude	0 - 100 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		Majority (50-90%)		Rapid Declines		Medium Impact: 7
		Stresses Ecosystem conversion
Biological resource use	Logging & wood harvesting - Unintentional effects: (subsistence/small scale) [harvest]	Timing		Scope		Severity		Impact
		Ongoing		Majority (50-90%)		Slow, Significant Declines		Medium Impact: 6
		Stresses Ecosystem degradation
Natural system modifications	Dams & water management/use - Large dams	Timing		Scope		Severity		Impact
		Future		Minority (<50%)		Very Rapid Declines		Low Impact: 5
		Stresses Ecosystem conversion
Natural system modifications	Dams & water management/use - Small dams	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Rapid Declines		Medium Impact: 6
		Stresses Ecosystem degradation, Ecosystem conversion
Natural system modifications	Fire & fire suppression - Increase in fire frequency/intensity	Timing		Scope		Severity		Impact
		Ongoing		Majority (50-90%)		Rapid Declines		Medium Impact: 7
		Stresses Ecosystem degradation

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Recommended citation
BirdLife International (2024) Species factsheet: Hoary-throated Spinetail Synallaxis kollari. Downloaded from https://datazone.birdlife.org/species/factsheet/hoary-throated-spinetail-synallaxis-kollari on 24/12/2024.
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 24/12/2024.