Dartford Warbler Curruca undata


Taxonomic note
Previously placed in Sylvia (del Hoyo and Collar 2016) but moved to current genus following Cai et al. (2019). Geographical variation rather limited and partially clinal; nominate subspecies intergrades widely with dartfordiensis in SW France and NW Iberia and with toni in S Iberia. Proposed subspecies corsa (from Corsica) and naevalbens (from SE Italy) fall within range of variation of nominate and thus are synonymized with it; similarly, aremorica (from NW France) is synonymized with dartfordiensis, and tingitana (from Morocco) with toni. Three subspecies recognized.

Taxonomic source(s)
Handbook of the Birds of the World and BirdLife International. 2021. Handbook of the Birds of the World and BirdLife International digital checklist of the birds of the world. Version 6. Available at: http://datazone.birdlife.org/userfiles/file/Species/Taxonomy/HBW-BirdLife_Checklist_v6_Dec21.zip.

IUCN Red List criteria met and history
Red List criteria met
Critically Endangered Endangered Vulnerable
- - -

Red List history
Year Category Criteria
2022 Near Threatened A2bc+3bc+4bc
2016 Near Threatened A2b+3b+4b
2012 Near Threatened A2b+3b+4b
2008 Near Threatened A2b; A3b; A4b
2004 Least Concern
2000 Lower Risk/Least Concern
1994 Lower Risk/Least Concern
1988 Lower Risk/Least Concern
Species attributes

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) 3,110,000 km2 medium
Extent of Occurrence (non-breeding) 4,180,000 km2 medium
Severely fragmented? no -
Estimate Data quality Derivation Year of estimate
Population size 1400000-3400000 mature individuals medium estimated 2018
Population trend decreasing medium estimated 2015-2025
Rate of change over the past 10 years/3 generations (longer of the two periods) 20-29% - - -
Rate of change over the future 10 years/3 generations (longer of the two periods) 20-29% - - -
Rate of change over the past & future 10 years/3 generations (longer of the two periods) 20-29% - - -
Generation length 2.94 years - - -
Number of subpopulations 3-100 - - -

Population justification: In Europe, the breeding population is estimated to number 597,000-1,430,000 pairs, which equates to approximately 1,200,000-2,900,000 mature individuals and 1,800,000-4,300,000 individuals (BirdLife International 2021). Europe forms c.85% of the global range, so a very preliminary estimate of the global population size is 1,400,000-3,400,000 mature individuals and 2,100,000-5,100,000 individuals although further validation of this estimate is needed.

Trend justification: Trend data is provided from the European range. As Europe holds c. 85% of the global population, these trends are held to reflect the global population. The European population underwent a large decline during 1970-1990 (Tucker and Heath 1994), and has continued to decline. BirdLife International (2021) estimate a 7.9% decrease between 2007-2018, or 10 years; however, considering trends calculated by the Spanish Common Bird Monitoring Scheme (SACRE) and the Pan-European Common Bird Monitoring Scheme (PECBMS; EBCC 2018), it's likely that the 10 year decline falls between 20-30%. PECBMS estimates a 15% decline between 2007-2016 (10 years). Between 1980-2018, BirdLife International (2021) estimates a 38% decline in Europe, and PECBMS a 37% decline between 1996-2016. Whilst populations in Portugal and the United Kingdom are increasing, declines have been reported for both France and Italy. The population has undergone a strong increase in Portugal (A. Meirinho in litt. 2016, Regos et al. 2016) possibly owing to the availability of burnt areas (S. Herrando in litt. 2016).  In the U.K. it has recently increased rapidly and extended its range northwards, reaching a total of 3,214 territories in 2006 (Wotton et al. 2009), and 1,677 territories in 2015. The last full survey, in 2006, coming after a long run of mild winters, may have recorded the population at or close to its peak (Holling et al. 2017). Keller et al. (2020) also shows an increase in breeding range across the U.K. between EBBA1 and EBBA2 (European Breeding Bird Atlas), in line with climate predicitions (Huntley et al. 2008). The population in France declined by at least 50% between 2001 and 2014 (E. Green in litt. 2016). In Italy, the population is declining although it is unclear to what extent (Monitoraggio Italiano Ornitologico and Lega Italiana Protezione Uccelli in litt. 2016). The species has abandoned previously occupied areas in Northern France, Southern Italy and Sicily (Keller et al. 2020).The population trend is unknown in Andorra (20-30 pairs). The overall population trend is therefore estimated to be decreasing at a rate of 20-29% over three generations, and is suspected to continue at the same rate between over the next ten years.

Country/territory distribution
Country/Territory Presence Origin Resident Breeding visitor Non-breeding visitor Passage migrant
Algeria extant native yes
Andorra extant native yes
Belgium extant vagrant yes
Croatia extant vagrant yes
Czechia extant vagrant yes
France extant native yes
Germany extant vagrant yes
Gibraltar (to UK) extant native yes
Greece extant vagrant yes
Ireland extant vagrant yes
Italy extant native yes
Libya extant vagrant yes
Malta extant native yes
Montenegro extant vagrant
Morocco extant native yes
Netherlands extant vagrant yes
Portugal extant native yes
Serbia extant vagrant
Spain extant native yes
Sweden extant vagrant yes
Switzerland extant vagrant yes
Tunisia extant native yes
Türkiye extant vagrant yes
United Kingdom extant native yes

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name
France Champ de Tir du Poteau
France Baie des Veys et Marais du Cotentin
France Iles Chausey
France Marais de la Baie d'Audierne
France Vallée du Régino
France Massifs de Fontainebleau et zones humides adjacentes
France Hautes Corbières
France Basses Corbières
France Hautes garrigues du Montpellierais
France Minervois
France Gorges de la Dourbie et causses avoisinants
France Chaîne des Alpilles
France Montagne Sainte-Victoire
France Massif du Petit Lubéron
France Plaine des Maures
France Le Pinail, Forêt de Moulière et bois du Défens
Portugal Serra de Penha Garcia e Campina de Toulões
Portugal Serra de Monchique
Portugal Luzianes
United Kingdom Ashdown Forest
United Kingdom Dorset Heaths and Forests
United Kingdom East Devon Heaths
United Kingdom Haldon Forest
United Kingdom New Forest
United Kingdom Poole Harbour
United Kingdom Thames Basin Heaths
United Kingdom Wealden Heaths
Italy Asinara island, Piana island and Stintino peninsula
Italy Arezzo heathlands
Italy Tuscan Archipelago
Italy Eolie islands
Italy Madonie
Spain La Cabrera mountain range
Spain Peña Labra and Cordel mountain ranges
Spain Fausilla mountains
Spain Rosarito and Navalcán reservoirs-La Iglesuela (Tietar valley)
Spain El Rebollar

Habitats & altitude
Habitat (level 1) Habitat (level 2) Importance Occurrence
Artificial/Terrestrial Plantations suitable resident
Grassland Subtropical/Tropical Dry suitable non-breeding
Marine Intertidal Salt Marshes (Emergent Grasses) suitable non-breeding
Shrubland Mediterranean-type Shrubby Vegetation major resident
Shrubland Temperate suitable resident
Altitude 0 - 2000 m Occasional altitudinal limits  

Threats & impact
Threat (level 1) Threat (level 2) Impact and Stresses
Agriculture & aquaculture Livestock farming & ranching - Agro-industry grazing, ranching or farming Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Declines Low Impact: 5
Ecosystem degradation
Agriculture & aquaculture Wood & pulp plantations - Agro-industry plantations Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Declines Low Impact: 5
Ecosystem conversion
Climate change & severe weather Temperature extremes Timing Scope Severity Impact
Ongoing Majority (50-90%) Slow, Significant Declines Medium Impact: 6
Species mortality
Human intrusions & disturbance Recreational activities Timing Scope Severity Impact
Ongoing Minority (<50%) Unknown Unknown
Species disturbance
Natural system modifications Fire & fire suppression - Trend Unknown/Unrecorded Timing Scope Severity Impact
Ongoing Majority (50-90%) Slow, Significant Declines Medium Impact: 6
Ecosystem degradation

Recommended citation
BirdLife International (2024) Species factsheet: Curruca undata. Downloaded from https://datazone.birdlife.org/species/factsheet/dartford-warbler-curruca-undata on 21/02/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from https://datazone.birdlife.org on 21/02/2024.