• 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.

Red List criteria met

Critically Endangered	Endangered	Vulnerable
-	-	A2c+3c+4c

Red List history

Year	Category	Criteria
2023	Vulnerable	A2c+3c+4c
2016	Vulnerable	A2c+3c+4c
2012	Vulnerable	A2c+3c+4c
2008	Vulnerable	A2c; A3c; A4c
2004	Vulnerable
2000	Vulnerable
1994	Lower Risk/Near Threatened
1988	Near Threatened

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

	Estimate	Data quality
Extent of Occurrence (breeding/resident)	1,600,000 km2	medium
Severely fragmented?	no	-

	Estimate	Data quality	Derivation	Year of estimate
Population size	10000-19999 mature individuals	poor	suspected	2023
Population trend	decreasing	poor	inferred	2016-2027
Rate of change over the past 10 years/3 generations (longer of the two periods)	20-41,30-40%	-	-	-
Rate of change over the future 10 years/3 generations (longer of the two periods)	20-41,30-40%	-	-	-
Rate of change over the past & future 10 years/3 generations (longer of the two periods)	20-41,30-40%	-	-	-
Generation length	3.7 years	-	-	-
Number of subpopulations	2-100	-	-	-
Percentage of mature individuals in largest subpopulation	1-89%	-	-	-

Population justification: On Sumatra, if it is truly confined to the eastern coastline (sensu Eaton et al. 2021), as seems likely, the population may be very small as little suitable habitat remains. Recent records come from only Way Kambas National Park (Olah and Simay 2007, eBird 2023) and the Kampar Peninsula (RER 2017) where there is unlikely to be enough suitable habitat to support more than 1,000 mature individuals. On Borneo, it is evidently rare (and much-depleted), although the area of suitable habitat in Kalimantan remains comparatively large (Mann 2008) and even if the species occurs at a low density as records suggest, the population probably numbers in the thousands. Precautionarily, a population size of 10,000-19,999 is suspected, but such a value represents little more than a best guess, and requires urgent survey attention.

Trend justification: Caprimulgus concretus is thought to be declining rapidly in response to extensive forest cover loss across its range. In the absence of population data, forest cover loss is used as a proxy to estimate the rate of reduction over the past three generations (11.1 years: 2012-2023), however doing this accurately relies on robust knowledge of the species' distribution when forest cover was more extensive. There is, however, much uncertainty on how widespread it was historically, and its precise habitat requirements (e.g. its persistence in plantations/degraded forest) remain poorly elucidated. Under a range of scenarios, forest cover loss in the species' mapped range is thought to have reduced by 20-41% over the last three generations (Global Forest Watch 2023, based on data from Hansen et al. [2013] and methods disclosed therein). Precautionarily, towards the upper limit of these losses (30-40%) is accepted here given the species' apparent confinement to specialised habitat. This rate of loss is also suspected to occur into the future, with comparatively little of the species' range circumscribed by protected areas (UNEP-WCMC and IUCN 2023), and most of it accessible for exploitation.

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

Country/Territory	IBA Name
Brunei	Brunei Bay
Indonesia	Danau Sentarum
Indonesia	Gunung Niut-Poteng
Indonesia	Way Kambas
Malaysia	Danum Valley Conservation Area

Habitat (level 1)	Habitat (level 2)	Importance	Occurrence
Forest	Subtropical/Tropical Moist Lowland	major	resident
Altitude	0 - 500 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		Majority (50-90%)		Slow, Significant Declines		Medium Impact: 6
		Stresses Ecosystem degradation, Ecosystem conversion
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
Biological resource use	Logging & wood harvesting - Unintentional effects: (large scale) [harvest]	Timing		Scope		Severity		Impact
		Ongoing		Majority (50-90%)		Slow, Significant Declines		Medium Impact: 6
		Stresses Ecosystem degradation
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
Natural system modifications	Fire & fire suppression - Increase in fire frequency/intensity	Timing		Scope		Severity		Impact
		Ongoing		Majority (50-90%)		Unknown		Unknown
		Stresses Ecosystem degradation

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Recommended citation
BirdLife International (2024) Species factsheet: Bonaparte's Nightjar Caprimulgus concretus. Downloaded from https://datazone.birdlife.org/species/factsheet/bonapartes-nightjar-caprimulgus-concretus on 23/11/2024.
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 23/11/2024.