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

Taxonomic note
Pseudastur occidentalis (del Hoyo and Collar 2014) was previously placed in the genus Leucopternis.

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(ii)

Red List history

Year	Category	Criteria
2024	Vulnerable	C2a(ii)
2016	Endangered	C2a(i)
2012	Endangered	C2a(i)
2008	Endangered	C2a(i)
2004	Endangered
2000	Endangered
1996	Endangered
1994	Endangered
1988	Threatened

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

	Estimate	Data quality
Extent of Occurrence (breeding/resident)	112,170 km2	medium
Severely fragmented?	no	-

	Estimate	Data quality	Derivation	Year of estimate
Population size	2500-10000,2600 mature individuals	poor	estimated	2023
Population trend	decreasing	poor	inferred	2017-2040
Rate of change over the past 10 years/3 generations (longer of the two periods)	1-19%	-	-	-
Rate of change over the past & future 10 years/3 generations (longer of the two periods)	1-9%	-	-	-
Generation length	7.52 years	-	-	-
Number of subpopulations	1	-	-	-
Percentage of mature individuals in largest subpopulation	100%	-	-	-

Population justification: Based on transect counts in different forest types in northwest Peru, the population density was calculated at 0.65 individuals/km² (Piana 2016). Within the range, a total of c.24,000 km² are covered by forest (Global Forest Watch 2023, using Hansen et al. [2013] data and methods therein). To account for the species' patchy distribution (see eBird 2023) and for the fact that many forest patches are too small and remote to offer suitable habitat (see Global Forest Watch 2023), it is precautionarily assumed that only 25% of forested habitat are occupied at this density (i.e., 6,000 km²). The global population may consequently number 3,900 individuals, which equates to 2,600 mature individuals. To account for uncertainty it is assumed that up to a potential maximum of 75% of forests may be occupied, giving an upper bound of 11,700 individuals or 7,800 mature individuals. Given the patchy nature of records and the species' general scarcity throughout the range the best estimate is set at the lower occupancy threshold and the population is estimated at between 2,500-8,000 with a best single value of 2,600 mature individuals.

Trend justification: This species is inferred to be declining as a consequence of habitat destruction and fragmentation; moreover, it is locally persecuted due to attacks on poultry. Blandariz et al. (2023) conducted analysis of expert responses on species change in western Ecuador and gave the species the highest score for 'retraction', corresponding to statements reporting loss from formerly occupied sites. Up until the 1980s, deforestation in western Ecuador proceeded rapidly at a rate of 57% per decade (Dodson and Gentry 1991), so that now mostly small fragments remain (see Global Forest Watch 2023). Forest loss has however since slowed and tree cover was lost at a rate of 9% over the past three generations (22.6 years), but from 2017 onward this slowed further to a rate equivalent to 4% over three generations (Global Forest Watch 2023, using Hansen et al. [2013] data and methods disclosed therein). Even considering the species' dependence on deciduous forests, and accounting for additional impacts of habitat degradation and fragmentation as well as hunting, population declines are likely slow. They are here tentatively placed in the band 1-19% over the past three generations, and slowing to 1-9% over three generations from 2017 onward.

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

Country/Territory	IBA Name
Ecuador	Abras de Mantequilla
Ecuador	Alamor-Celica
Ecuador	Bosque Protector Cerro Blanco
Ecuador	Bosque Protector Cerro Pata de Pájaro
Ecuador	Bosque Protector Chongón-Colonche
Ecuador	Bosque Protector Jatumpamba-Jorupe
Ecuador	Bosque Protector Molleturo Mullopungo
Ecuador	Cañón del río Catamayo
Ecuador	Cazaderos-Mangaurquillo
Ecuador	Centro Científico Río Palenque
Ecuador	Cerro de Hayas-Naranjal
Ecuador	Cerro Mutiles
Ecuador	Daucay
Ecuador	Hacienda Camarones
Ecuador	La Tagua
Ecuador	Mache Chindul Ecological Reserve and surrouding areas (Reserva Ecológica Mache-Chindul IBA)
Ecuador	Parque Nacional Machalilla y alrededores
Ecuador	Reserva Biológica Tito Santos
Ecuador	Reserva Buenaventura
Ecuador	Reserva Ecológica Comunal Loma Alta
Ecuador	Reserva Ecológica Manglares-Churute y Canal de Jambelí
Ecuador	Reserva Natural Tumbesia-La Ceiba-Zapotillo
Peru	Parque Nacional Cerros de Amotape

Habitat (level 1)	Habitat (level 2)	Importance	Occurrence
Forest	Subtropical/Tropical Dry	major	resident
Forest	Subtropical/Tropical Moist Lowland	major	resident
Altitude	0 - 2900 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%)		Slow, Significant Declines		Medium Impact: 6
		Stresses Ecosystem degradation, Ecosystem conversion
Agriculture & aquaculture	Livestock farming & ranching - Small-holder grazing, ranching or farming	Timing		Scope		Severity		Impact
		Ongoing		Majority (50-90%)		Slow, Significant Declines		Medium Impact: 6
		Stresses Ecosystem degradation, Ecosystem conversion
Biological resource use	Hunting & trapping terrestrial animals - Persecution/control	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Slow, Significant Declines		Low Impact: 5
		Stresses Species mortality
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%)		Negligible declines		Low Impact: 4
		Stresses Ecosystem degradation, Ecosystem conversion

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Recommended citation
BirdLife International (2024) Species factsheet: Grey-backed Hawk Pseudastur occidentalis. Downloaded from https://datazone.birdlife.org/species/factsheet/grey-backed-hawk-pseudastur-occidentalis 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.