• Summary
• Text account
• Data table and detailed info
• Distribution map
• Climate Change maps
• 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
-	-	-

Red List history

Year	Category	Criteria
2024	Least Concern
2016	Least Concern
2012	Least Concern
2009	Least Concern
2008	Least Concern
2004	Least Concern
2000	Lower Risk/Least Concern
1994	Lower Risk/Least Concern
1988	Lower Risk/Least Concern

Migratory status	not a migrant	Forest dependency	does not normally occur in forest
Land-mass type		Average mass	-

	Estimate	Data quality
Extent of Occurrence (breeding/resident)	25,900,000 km2	medium
Severely fragmented?	no	-

	Estimate	Data quality	Derivation	Year of estimate
Population size	8500-20000 mature individuals	poor	suspected	2021
Population trend	decreasing	-	inferred	-
Rate of change over the future 10 years/3 generations (longer of the two periods)	10-19%	-	-	-
Generation length	5.55 years	-	-	-
Number of subpopulations	2-20	-	-	-
Percentage of mature individuals in largest subpopulation	1-89%	-	-	-

Population justification: The species is locally common, but has declined in parts of its range, such as Uganda (Carswell et al. 2005). The West African population was suspected to number less than 1,000 individuals at the start of the century (Kear 2005), and less than 500 individuals in 2006 (Dodman 2007, Wetlands International 2021). The overall population in Eastern and Southern Africa was estimated in 2002 to be between 10,000 and 25,000 individuals (Wetlands International 2021), with censuses of 500 individuals at both Lake Naivasha in Kenya and Kafue Flats in Zambia (Dowsett 2008). Subspecies insularis has historically been widespread across Madagascar, but may now be rarer due to local extinctions, with the most recent estimate of 2,500-5,000 individuals (Dodman 2007, Wetlands International 2021). Based on these estimates, the total population size is suspected to be between 13,000 and 30,000 individuals, which is equal to 8,666-20,000 mature individuals, rounded to 8,500-20,000.

Trend justification: The overall trend is decreasing, although some populations may be stable (Wetlands International 2021). The West African population seems to be decreasing with less than 1,000 individuals at the start of the century (Kear 2005), and less than 500 individuals in 2006 (Dodman 2007, Wetlands International 2021), although coverage is poor is this region. Similarly, local extinctions in Madagascar, such as at Lake Alaotra (Bamford et al. 2015) are likely contributing to a decreasing population size of subspecies insularis. Climate change modelling has projected this species will be likely to suffer a range contraction by 2050, with its current range reduced by up to 30% over approximately 50 years (Nagy et al. 2021), equivalent to 10 to 11 % over three generations. Considering the potential for additional reductions due to localised hunting, and assuming that the rate of habitat loss as measured directly relates to features that limit the species' population, future reductions are suspected to occur at a rate of between 10-19 %.

Country/Territory	Presence	Origin	Resident	Breeding visitor	Non-breeding visitor	Passage migrant
Angola	extant	native	yes
Benin	extant	vagrant
Botswana	extant	native	yes
Burkina Faso	extant	vagrant
Burundi	extant	native	yes
Cameroon	extant	native	yes
Chad	extant	native	yes
Congo	extant	native	yes
Congo, The Democratic Republic of the	extant	native	yes
Eswatini	extant	native	yes
Ethiopia	extant	native	yes
Kenya	extant	native	yes
Lesotho	extant	native	yes
Madagascar	extant	native	yes
Malawi	extant	native	yes
Mali	extant	native	yes
Mauritania	extant	vagrant
Mozambique	extant	native	yes
Namibia	extant	native	yes
Nigeria	extant	native	yes
Rwanda	extant	native	yes
Senegal	extant	native	yes
Somalia	extant	vagrant
South Africa	extant	native	yes
South Sudan	extant	native	yes
Sudan	extant	vagrant
Tanzania	extant	native	yes
Togo	extant	vagrant
Uganda	extant	native	yes
Zambia	extant	native	yes
Zimbabwe	extant	native	yes

Country/Territory	IBA Name
Botswana	Okavango Delta
South Africa	Grasslands
South Africa	Nyl River Floodplain
Zambia	Sumbu National Park and Tondwa Game Management Area

Habitat (level 1)	Habitat (level 2)	Importance	Occurrence
Wetlands (inland)	Permanent Freshwater Lakes (over 8ha)	suitable	resident
Wetlands (inland)	Permanent Freshwater Marshes/Pools (under 8ha)	major	resident
Wetlands (inland)	Seasonal/Intermittent Freshwater Lakes (over 8ha)	suitable	resident
Altitude	0 - 3000 m	Occasional altitudinal limits

Threat (level 1)	Threat (level 2)	Impact and Stresses
Biological resource use	Fishing & harvesting aquatic resources - Unintentional effects: (subsistence/small scale) [harvest]	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 - Intentional use (species is the target)	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Slow, Significant Declines		Low Impact: 5
		Stresses Species mortality
Biological resource use	Hunting & trapping terrestrial animals - Unintentional effects (species is not the target)	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Slow, Significant Declines		Low Impact: 5
		Stresses Species mortality
Climate change & severe weather	Habitat shifting & alteration	Timing		Scope		Severity		Impact
		Future		Minority (<50%)		Slow, Significant Declines		Low Impact: 3
		Stresses Species disturbance, Ecosystem degradation
Invasive and other problematic species, genes & diseases	Invasive non-native/alien species/diseases - Unspecified species	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Rapid Declines		Medium Impact: 6
		Stresses Indirect ecosystem effects, Ecosystem degradation
Pollution	Agricultural & forestry effluents - Soil erosion, sedimentation	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Slow, Significant Declines		Low Impact: 5
		Stresses Ecosystem degradation

Purpose	Scale
Food - human	subsistence, national

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Recommended citation
BirdLife International (2024) Species factsheet: White-backed Duck Thalassornis leuconotus. Downloaded from https://datazone.birdlife.org/species/factsheet/white-backed-duck-thalassornis-leuconotus 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.