Aquatic Warbler Acrocephalus paludicola


Taxonomic note
Normally considered probably closest to A. melanopogon, although genetic data are contradictory on this point (Arbabi et al. 2014, Fregin et al. 2009). Monotypic.

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.

IUCN Red List criteria met and history
Red List criteria met
Critically Endangered Endangered Vulnerable
- - B2ab(i,ii,iii,iv,v)

Red List history
Year Category Criteria
2022 Vulnerable B2ab(i,ii,iii,iv,v)
2016 Vulnerable A2c
2013 Vulnerable A2c
2012 Vulnerable A2c
2008 Vulnerable A2c
2004 Vulnerable
2000 Vulnerable
1996 Vulnerable
1994 Vulnerable
1988 Threatened
Species attributes

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

Estimate Data quality
Extent of Occurrence breeding/resident (km2) 580,000 medium
Extent of Occurrence non-breeding (km2) 1,320,000 medium
Area of Occupancy breeding/resident (km2) 1,540 medium
Number of locations 9-20,10 -
Severely fragmented? no -
Population and trend
Value Data quality Derivation Year of estimate
Number of mature individuals 18000-29000 medium estimated 2018
Population trend decreasing medium inferred 2016-2026
Decline % (10 years/3 generations future) 10-19 - - -
Decline % (10 years/3 generations past and future) 10-19 - - -
Number of subpopulations 4-60 - - -
Percentage in largest subpopulation 67-98 - - -
Generation length (years) 2.31 - - -

Population justification:

In Europe, the breeding population is estimated to number 9,100-14,300 calling males, which equates to approximately 18,000-29,000 mature individuals and 27,000-43,000 individuals (BirdLife International 2021). The entire breeding population is contained within Europe, with 99% of the population found in Poland, Belarus and Ukraine (the Central European subpopulation), so an estimate of the global population size is 18,000-29,000 mature individuals. Furthermore, previous research from Tanneberger and Kubacka (2018) estimated the global population to be less than 11,000 singing males, while Briedis and Keišs (2016) provided a range of 11,000-16,000 singing males, or 22,000-32,000 mature individuals.

Trend justification: The west Siberian population in European Russia is probably extinct, with the last confirmed record in 2000 (Tanneberger and Kubacka 2018). The Hungarian subpopulation collapsed from c. 700 singing males to 331 in 2002, with another collapse in 2006, and a final collapse in 2012 – no singing males have been observed since (Végvári and Flade 2012). There are varying rates of decline across the global range, less than previously observed. While it appears that the large population in Poland is stable or even increasing, the Belarus population declined by 47-55% between 2000-2011 (BirdLife International 2015) and the Pomeranian population has declined to critical levels. The Lithuanian population appears to have recovered since 2013 to 247 s.m. in 2016 (Ž. Morkv?nas in litt. 2016).
In Europe, the population size is estimated to be decreasing by approximately 15% in 10 years (Birdlife International 2021). While the global population appears stable, some subpopulations are declining (Tanneberger and Kubacka 2018) as well as extinction of small peripheral populations (Zmihorski et al. 2016). Fluctuations from large breeding sites, as well as the weakness of counting methods, may also be masking a slow decline. Harmful impacts from pollutants may be an emerging issue, but its impact on the population has not been investigated (Pacyna et al. 2018).
As the majority of the breeding population is contained within Europe, and in the face of possible local extinctions, the global population is inferred to be declining at a rate of 10-19% over 10 years, primarily due to severe habitat degradation.

Country/territory distribution
Country/Territory Presence Origin Resident Breeding Non-breeding Passage
Algeria extant native yes
Andorra extant uncertain yes
Austria extinct native yes
Belarus extant native yes
Belgium extant native yes
Bulgaria extant native yes
Burkina Faso extant uncertain yes yes
Croatia extant native
Cyprus extant vagrant
Czechia extant native yes
Denmark extant vagrant
Egypt extant vagrant
Estonia extant vagrant
Finland extant vagrant
France extant native yes
Germany extant native yes yes
Ghana extant native yes
Greece extant vagrant
Hungary extinct native yes
Ireland extant vagrant
Israel extant vagrant
Italy extant native yes
Kazakhstan extant vagrant
Latvia extant native yes
Lithuania extant native yes
Luxembourg extant native yes
Mali extant uncertain yes
Malta extant vagrant
Mauritania extant native yes
Montenegro extinct native yes
Morocco extant native yes
Netherlands extant native yes
North Macedonia extant vagrant
Norway extant vagrant
Poland extant native yes
Portugal extant native yes
Romania extant native yes
Russia possibly extinct native yes
Russia (Central Asian) possibly extinct native yes
Russia (European) possibly extinct native yes
San Marino extant uncertain yes
Senegal extant native yes
Serbia extinct native yes
Slovakia extinct native yes
Slovenia extant native yes
Spain extant native yes
Sweden extant vagrant
Switzerland extant native yes
Tunisia extant vagrant
Türkiye extant vagrant
Ukraine extant native yes
United Kingdom extant native yes
Western Sahara extant native yes

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name
Belarus Balota Dzikoje
Belarus Balota Zvaniec
Belarus Mid Prypiac'
Belarus Vyhanaščanskija baloty
Russia (European) Watershed of Bityug and Tsna rivers
Russia (European) Nizhnekamskaya flood-plain
Russia (European) Kamsko-Yayvenski wetland
Ukraine Supij marsh
Ukraine Shats'ki lakes
Ukraine Pryp'yat' river valley
Ukraine Stokhod river valley
Ukraine Turiya river valley
France Marais de la Baie d'Audierne
France Estuaire de la Gironde : marais de la rive nord
Germany Barnbruch
Germany Danube valley: Regensburg-Vilshofen
Germany Wagbach lowlands
Ukraine Svydovets protected area
Belarus Sporaŭskaje balota
Ukraine Styr' river valley (Kolky village)
Ukraine Udaj river valley
Ukraine Syra Pogonya mire
Russia (European) Neman river Delta and the coast of the Curonian Bay
Belarus Prostyr
Belarus Servač
Belarus Lelchitsy-Ubort
Latvia Liepaja lake
Lithuania Zuvintas Biosphere Reserve
United Kingdom Marazion Marsh
United Kingdom Weymouth Wetlands
Hungary Hortobágy and Tisza-to
Germany Greifswalder Bodden
Germany Peenetal (Peenetalmoor and Anklamer Stadtbruch)
Germany Lower Oder valley
Luxembourg Valley of the Syre
Luxembourg Upper Valley of the Alzette
Poland Siemianowka Reseirvoir
Belarus Dzivin - Vialiki Lies
Lithuania Flooded coastal meadows near Tyrai bog
Lithuania Flooded coastal meadows near Svencele raised-bog
Lithuania Nemunas delta regional Park
Lithuania Flooded meadows near Sausgalviai settlement
Poland Delta of the Swina river
Poland Lower Odra river valley
Poland Miedwie site
Poland Rozwarowo Marshes
Poland Biebrza river valley
Poland Upper Narew River Valley
Poland Marshy Valley of the Narew River
Poland Wizna Swamps
Poland Narew river gaps
Poland Warta River Mouth
Poland Ner River Valley
Poland Kampinos forest
Poland Bubnow Marsh
Poland Middle Bug river valley
Poland Chelm calcareous marshes
Belarus Ščara floodplain
Spain Chingudi-Bidasoa estuary
Spain Tierra de Campos steppes
Spain Carrión-Frómista
Spain Salburua
Spain Esteiro do Miño
Spain Páramo Bajo de León
Belarus Haradzienskaja Svislač

Habitats & altitude
Habitat (level 1) Habitat (level 2) Importance Occurrence
Artificial/Terrestrial Pastureland suitable non-breeding
Artificial/Terrestrial Pastureland suitable breeding
Wetlands (inland) Bogs, Marshes, Swamps, Fens, Peatlands major non-breeding
Wetlands (inland) Bogs, Marshes, Swamps, Fens, Peatlands major breeding
Altitude 0 - 653 m Occasional altitudinal limits  

Threats & impact
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
Ecosystem degradation, Ecosystem conversion
Agriculture & aquaculture Livestock farming & ranching - Agro-industry grazing, ranching or farming Timing Scope Severity Impact
Ongoing Majority (50-90%) Slow, Significant Declines Medium Impact: 6
Ecosystem degradation, Ecosystem conversion
Biological resource use Gathering terrestrial plants - Unintentional effects (species is not the target) Timing Scope Severity Impact
Ongoing Majority (50-90%) Slow, Significant Declines Medium Impact: 6
Ecosystem degradation
Climate change & severe weather Droughts Timing Scope Severity Impact
Ongoing Majority (50-90%) Slow, Significant Declines Medium Impact: 6
Ecosystem degradation
Natural system modifications Dams & water management/use - Large dams Timing Scope Severity Impact
Ongoing Majority (50-90%) Slow, Significant Declines Medium Impact: 6
Ecosystem degradation
Natural system modifications Fire & fire suppression - Increase in fire frequency/intensity Timing Scope Severity Impact
Ongoing Majority (50-90%) Slow, Significant Declines Medium Impact: 6
Ecosystem degradation, Ecosystem conversion, Species mortality
Pollution Agricultural & forestry effluents - Nutrient loads Timing Scope Severity Impact
Future Unknown Slow, Significant Declines Unknown
Ecosystem degradation, Ecosystem conversion

Purpose Primary form used Life stage used Source Scale Level Timing
Pets/display animals, horticulture - - international non-trivial recent

Recommended citation
BirdLife International (2023) Species factsheet: Acrocephalus paludicola. Downloaded from on 29/09/2023. Recommended citation for factsheets for more than one species: BirdLife International (2023) IUCN Red List for birds. Downloaded from on 29/09/2023.