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

Taxonomic note

Ninox squamipila, N. hypogramma, N. hantu and N. forbesi (del Hoyo and Collar 2014) were previously lumped as N. squamipila following Norman et al. (1998), and before then were also lumped with N. natalis as N. squamipila following Sibley and Monroe (1990, 1993). Formerly considered conspecific with N. squamipila (which see), but separable on morphological and plumage details, molecular differences and perhaps voice (Norman et al. 1998). Monotypic.

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
-	D	D1

Red List history

Year	Category	Criteria
2022	Vulnerable	D1
2016	Vulnerable	D2
2013	Vulnerable	D2
2012	Vulnerable	D2
2008	Vulnerable	D2
2007	Vulnerable
2006	Vulnerable
2004	Vulnerable
2000	Critically Endangered
1994	Not Recognised
1988	Not Recognised

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

	Estimate	Data quality
Extent of Occurrence (breeding/resident)	240 km2	medium
Area of Occupancy (breeding/resident)	216 km2
Severely fragmented?	no	-

	Estimate	Data quality	Derivation	Year of estimate
Population size	240-1200, 340 mature individuals	medium	estimated	2020
Population trend	stable	poor	estimated	-
Generation length	5.02 years	-	-	-
Number of subpopulations	1	-	-	-
Percentage of mature individuals in largest subpopulation	100%	-	-	-

Population justification: About 342 mature Christmas Island Boobooks were thought to be present on the island in 2016 based on call playback at 135 sites (Morcombe 2016). This is higher than suggested by Low and Hamilton (2013) who suggested a population size in the range 1-100 pairs based on call playback surveys, but lower than the estimates of Hill and Lill (1998), who postulated a population of 820–1,200 birds based on the areas occupied by six radio-tracked individuals in the 1990s. Based on these estimates, Macgregor et al. (2021) estimate the total number of mature individuals to be in the range 240-1,200, with a best estimate of 340.

Trend justification: Control of the ants may have allowed the species' population to stabilise in the past (S. Garnett in litt. 2005), although there is no evidence of past declines or fluctuations (D. James in litt. 2007). There is currently no evidence of a continuing decline. Reporting rates and occupancy at 105 sites in 2006, annually from 2012 to 2017, and in 2019 are suggestive of an overall stable population (James and McAllan 2014, Director of National Parks unpublished, Legge and Woinarski unpublished).

Country/Territory	Presence	Origin	Resident	Breeding visitor	Non-breeding visitor	Passage migrant
Christmas Island (to Australia)	extant	native	yes

Country/Territory	IBA Name
Christmas Island (to Australia)	Christmas Island

Habitat (level 1)	Habitat (level 2)	Importance	Occurrence
Forest	Subtropical/Tropical Moist Lowland	major	resident
Shrubland	Subtropical/Tropical Moist	suitable	resident
Altitude	0 - 360 m	Occasional altitudinal limits

Threat (level 1)	Threat (level 2)	Impact and Stresses
Climate change & severe weather	Habitat shifting & alteration	Timing		Scope		Severity		Impact
		Future		Whole (>90%)		Unknown		Unknown
		Stresses Indirect ecosystem effects, Ecosystem degradation
Energy production & mining	Mining & quarrying	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Negligible declines		Low Impact: 4
		Stresses Species disturbance, Ecosystem degradation, Ecosystem conversion
Invasive and other problematic species, genes & diseases	Invasive non-native/alien species/diseases - Anoplolepis gracilipes	Timing		Scope		Severity		Impact
		Ongoing		Whole (>90%)		Negligible declines		Medium Impact: 6
		Stresses Indirect ecosystem effects, Ecosystem degradation
Invasive and other problematic species, genes & diseases	Invasive non-native/alien species/diseases - Rattus rattus	Timing		Scope		Severity		Impact
		Ongoing		Unknown		Unknown		Unknown
		Stresses Reduced reproductive success, Species mortality
Invasive and other problematic species, genes & diseases	Invasive non-native/alien species/diseases - Unspecified species	Timing		Scope		Severity		Impact
		Future		Majority (50-90%)		Negligible declines		Low Impact: 3
		Stresses Species mortality

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Recommended citation
BirdLife International (2024) Species factsheet: Christmas Island Boobook Ninox natalis. Downloaded from https://datazone.birdlife.org/species/factsheet/christmas-island-boobook-ninox-natalis on 22/12/2024.
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 22/12/2024.