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

Taxonomic note
Symposiachrus leucurus (del Hoyo and Collar 2016) was previously listed as Monarcha leucurus.

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.

Red List criteria met

Critically Endangered	Endangered	Vulnerable
-	-	-

Red List history

Year	Category	Criteria
2022	Near Threatened	B1b(ii,iii)+2b(ii,iii)
2016	Near Threatened	B1ab(iii)
2012	Near Threatened	B1ab(iii)
2008	Near Threatened	B1a+b(iii)
2004	Near Threatened
2000	Lower Risk/Near Threatened
1994	Lower Risk/Near Threatened
1988	Near Threatened

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

	Estimate	Data quality
Extent of Occurrence (breeding/resident)	3,200 km2	medium
Area of Occupancy (breeding/resident)	1,700 km2
Severely fragmented?	no	-

	Estimate	Data quality	Derivation	Year of estimate
Population size	50000-250000 mature individuals	-	suspected	2021
Population trend	decreasing	-	suspected	2013-2023
Rate of change over the past 10 years/3 generations (longer of the two periods)	5-15%	-	-	-
Rate of change over the future 10 years/3 generations (longer of the two periods)	5-15%	-	-	-
Rate of change over the past & future 10 years/3 generations (longer of the two periods)	5-15%	-	-	-
Generation length	3.37 years	-	-	-

Population justification: This species is described as common or very common (del Hoyo et al. 2006, Eaton et al. 2021). A close relative of this species, Symposiachrus loricatus of Buru, Indonesia, occurs at a density of 127-213 birds/km². Applying this density to the estimated AOO of 1,700 km² (the approximate amount of forest cover left in its range) yields a maximum population size of 215,900-362,100, equivalent to 143,00-240,000 mature individuals. Given this derives from a congener and not species-specific data, and the fact that not all of the AOO is likely to be occupied, the population size is placed here in the broad range of 50,000-250,000 mature individuals. It therefore does not meet or come close to the population size thresholds for listing as Threatened.

Trend justification: This species is suspected to be declining because of ongoing forest loss in its range. Between 2010 and 2020, forest cover loss (with a canopy cover of >30%) has averaged 0.74-1.09% per year in this species's range (Global Forest Watch 2021, using Hansen et al. [2013] data and methods disclosed therein), equivalent to a 7.5-11% decline over three generations (10.1 years; Bird et al. 2020). This rate fluctuates with some years worse than others; for example, in 2016 alone, c.2.4% of forest cover was lost. This species is moderately forest dependent and is suspected to be declining at a rate similar to that of forest loss; although it is tolerant of forest edge, much of the forest cover loss in the Kai Islands has been a result of total clearance for agriculture (in which the species cannot persist).

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

Country/Territory	IBA Name
Indonesia	Pegunungan Daab - Boo

Habitat (level 1)	Habitat (level 2)	Importance	Occurrence
Forest	Subtropical/Tropical Dry	major	resident
Forest	Subtropical/Tropical Moist Lowland	major	resident
Altitude	0 - 625 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	Wood & pulp plantations - Small-holder plantations	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Slow, Significant Declines		Low Impact: 5
		Stresses Ecosystem degradation, 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

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Recommended citation
BirdLife International (2024) Species factsheet: White-tailed Monarch Symposiachrus leucurus. Downloaded from https://datazone.birdlife.org/species/factsheet/white-tailed-monarch-symposiachrus-leucurus 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.