• 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. and Fishpool, L.D.C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Volume 1: Non-passerines. Lynx Edicions 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)	C2a(i)

Red List history

Year	Category	Criteria
2024	Endangered	C2a(i)
2016	Endangered	C2a(i)
2014	Endangered	C2a(i)
2012	Vulnerable	C2a(i)
2010	Vulnerable	C2a(i)
2008	Near Threatened	D1
2004	Near Threatened
2000	Lower Risk/Least Concern
1994	Lower Risk/Near Threatened
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)	4,680,000 km2	medium
Severely fragmented?	no	-

	Estimate	Data quality	Derivation	Year of estimate
Population size	1400-4200 mature individuals	poor	estimated	2023
Population trend	decreasing	poor	inferred	2000-2032
Rate of change over the past & future 10 years/3 generations (longer of the two periods)	20-29%	-	-	-
Generation length	10.55 years	-	-	-
Number of subpopulations	10-100	-	-	-
Percentage of mature individuals in largest subpopulation	1-89%	-	-	-

Population justification: The species is thought to be rare and patchily distributed (Thiollay 1994, Ferguson-Lees and Christie 2001).
The population in Venezuela is thought to number in the low hundreds or perhaps 200 mature individuals (C. J. Sharpe in litt. 2003, 2015). In Colombia, the population has been estimated at 320-640 mature individuals (Renjifo et al. 2014). The population in Ecuador has been placed in the band 50-249 mature individuals (Freile et al. 2019), while the population in Peru is thought to number not more than 330 mature individuals (SERFOR 2018). In Bolivia, the population numbers likely fewer than 250 mature individuals (S. K. Herzog in litt. 2013). The population in Argentina is placed in the band 250-2,499 mature individuals (MAyDS and AA 2017). Considering these national population estimates, the global population is here precautionarily placed in the band 1,400-4,200 mature individuals. The distribution range is highly disjunct; observational records (per eBird 2023) suggest that it forms at least ten very small subpopulations.

Trend justification: This species prefers dense primary forests (C. J. Sharpe in litt. 2003, T. Donegan in litt. 2010, Rivas-Fuenzalida et al. 2022), although it may persist in mosaics of primary and secondary forest with open areas (C. Márquez in litt. 2012). Throughout its range, tree cover has been lost at a rate equivalent to 7-9% over three generations (31.7 years), extrapolated from losses over 2000-2022 (Global Forest Watch 2023, using Hansen et al. [2013] data and methods disclosed therein). This value does however not account for the disturbance and degradation of habitat, which may exacerbate the overall rate of habitat loss. In addition to declines caused by forest loss, the species is suffering from high hunting and poaching pressure in many parts of its range; studies found direct mortality due to human-eagle conflict in over half of the territories investigated (Rivas-Fuenzalida et al. 2022, 2023). Due to the species' long generation length of 10.55 years and its slow reproduction, the killing of adults and poaching of nestlings is likely to have disproportionately high impacts on the population trend. Importantly, ongoing forest loss is increasing the risk of conflict and persecution (Restrepo-Cardona et al. 2019).
Based on ongoing forest loss throughout its range and reports of direct mortality, a continuing decline in the population size is inferred. Even though there is no direct quantification of the trend, the above information on the intensity of threats suggests that declines may approach 30% over three generations. Preliminarily therefore, they are here placed in the band 20-29% over three generations.

Country/Territory	Presence	Origin	Resident	Breeding visitor	Non-breeding visitor	Passage migrant
Argentina	extant	native	yes
Bolivia	extant	native	yes
Colombia	extant	native	yes
Ecuador	extant	native	yes
Peru	extant	native	yes
Venezuela	extant	native	yes

Country/Territory	IBA Name
Argentina	Cerro Negro de San Antonio
Argentina	Parque Nacional Calilegua
Colombia	Bosques del Oriente de Risaralda
Colombia	Cerro La Judía
Colombia	Cerro Pintado (Serranía de Perijá)
Colombia	Cuenca del Río Toche
Colombia	La Planada Natural Reserve
Colombia	Munchique Natural National Park and southern extension
Colombia	Parque Nacional Natural Macuira
Colombia	Parque Natural Regional Páramo del Duende
Colombia	Puracé Natural National Park
Colombia	Serranía de los Churumbelos
Colombia	Serranía de los Paraguas
Peru	Manu

Habitat (level 1)	Habitat (level 2)	Importance	Occurrence
Artificial/Terrestrial	Subtropical/Tropical Heavily Degraded Former Forest	marginal	resident
Forest	Subtropical/Tropical Moist Montane	major	resident
Altitude	450 - 3500 m	Occasional altitudinal limits	(min) 150 m

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	Livestock farming & ranching - Agro-industry 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	Hunting & trapping terrestrial animals - Persecution/control	Timing		Scope		Severity		Impact
		Ongoing		Majority (50-90%)		Slow, Significant Declines		Medium Impact: 6
		Stresses Species mortality
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
Transportation & service corridors	Utility & service lines	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Negligible declines		Low Impact: 4
		Stresses Species mortality

Purpose	Scale
Other (free text)	subsistence

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Recommended citation
BirdLife International (2024) Species factsheet: Black-and-chestnut Eagle Spizaetus isidori. Downloaded from https://datazone.birdlife.org/species/factsheet/black-and-chestnut-eagle-spizaetus-isidori on 22/11/2024.
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 22/11/2024.