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 (km2) 3,110,000 medium
Extent of Occurrence non-breeding (km2) 4,180,000 medium
Number of locations -
Severely Fragmented -
Population and trend
Value Data quality Derivation Year of estimate
No. of mature individuals 1400000-3400000 medium estimated 2018
Population trend Decreasing medium estimated -
Decline (3 years/1 generation past) - - -
Decline (5 years/1 generation past) - - -
Decline (10 years/1 generation past) - - -
Decline (10 years/3 generation future) 20-29 - - -
Decline (10 years/3 generation past and future) 20-29 - - -
Number of subpopulations 3-100 - - -
Percentage in largest subpopulation - - -

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 Occurrence status Presence Resident Breeding Non-breeding Passage
Algeria N Extant Yes
Andorra N Extant Yes
Belgium V Extant Yes
Croatia V Extant Yes
Czechia V Extant Yes
France N Extant Yes
Germany V Extant Yes
Gibraltar (to UK) N Extant Yes
Greece V Extant Yes
Ireland V Extant Yes
Italy N Extant Yes
Libya V Extant Yes
Malta N Extant Yes
Montenegro V Extant
Morocco N Extant Yes
Netherlands V Extant Yes
Portugal N Extant Yes
Serbia V Extant
Spain N Extant Yes
Sweden V Extant Yes
Switzerland V Extant Yes
Tunisia N Extant Yes
Turkey V Extant Yes
United Kingdom N Extant Yes

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name
Portugal Ria de Aveiro
Portugal Murta dam
Portugal Malcata mountains
Spain North and east coasts of Minorca and island of Aire
France Réserve Naturelle du courant d'Huchet
France Iles Chausey
France Baie du Mont Saint Michel et Ile des Landes
France Marais de la Baie d'Audierne
France Etangs de Leucate et Lapalme
France Gorges de la Vis et cirque de Navacelles
France Etangs Montpellierains
France Cordon lagunaire de Sète à Agde
France Etangs de Vendres, Pissevache et Lespignan
France Gorges du Rieutord-Fage-Cagnasses
France Petite Camargue fluvio-lacustre
France Crau
France Salins d'Hyères et de Pesquiers
France Vallée de la Loire : gorges de la Loire
France Champ de Tir du Poteau
France Estuaire de la Gironde : marais du Blayais
France Falaise du Bessin
France Baie des Veys et Marais du Cotentin
France Baies de Morlaix et de Carantec
France Ile d'Ouessant
France Brenne centrale
France Brenne: Forêt de la Petite-Brenne
France Brenne: Forêt de Lancosme
France Golfe de Porto, presqu'île de Scandola et golfe de Galeria
France Vallée du Régino
France Etang d'Urbino et zones humides périphériques
France Iles Finocchiarola et côte de Tamarone à Centuri
France Vallée du Verghello
France Massifs de Fontainebleau et zones humides adjacentes
France Montagne de la Clape
France Etangs Narbonnais
France Hautes Corbières
France Basses Corbières
France Massif des Albères
France Massif du Canigou-Carança
France Gorges du Gardon
France Hautes garrigues du Montpellierais
France Minervois
France Etangs de Canet et de Villeneuve-de-la-Raho et embouchure du Tech
France Montagnes de Marcou, de l'Espinouse et du Caroux
France Gorges de la Dourbie et causses avoisinants
France Camargue
France Chaîne des Alpilles
France Montagne Sainte-Victoire
France Iles Marseillaises: Maire, Jarron, Jarre, Riou, Calseraigne, Congloue et Pomègues
France Massif du Petit Lubéron
France Plateau de Valensole
France Plaine des Maures
France Préalpes de Grasse
France Le Pinail, Forêt de Moulière et bois du Défens
France Marais de Brière
France Marais poitevin et baie de l'Aiguillon
United Kingdom Avon Valley
United Kingdom Chesil Beach and the Fleet
United Kingdom Dorset Heaths and Forests
United Kingdom East Devon Heaths
United Kingdom Poole Harbour
United Kingdom Thames Basin Heaths
United Kingdom New Forest
United Kingdom Wealden Heaths
United Kingdom Ashdown Forest
United Kingdom Exmoor Coast and Heaths
United Kingdom Haldon Forest
Italy Eolie islands
Italy Cuglieri coast
Italy Cape Caccia and Conte port
Italy Gargano promontory
Italy Tuscan Archipelago
Italy Mount Beigua
Italy Circeo National Park
Italy Coast between Marina di Camerota and Policastro Bussentino
Italy Egadi islands
Italy Cape San Marco
Italy Alpi Apuane
Italy Arezzo heathlands
Italy Argentario
Italy Farma valley
Italy Uccellina mountains, Trappola marshes and Ombrone mouth
Italy Orbetello lagoon and Burano lake
Italy Furlo gorge and Mount Catria
Andorra Pirineo de Andorra
Italy Sinis and Oristano wetlands
Portugal Serra de Penha Garcia e Campina de Toulões
Portugal Serra de Monchique
Portugal Luzianes
France Arjuzanx
France Rade de Lorient
France Etang de Biguglia
France Anse de Fouras, baie d'Yves et marais de Rochefort
France Bonne Anse
France Cap Sizun
France Cap Frehel
France Forêt d'Orléans: massifs d'Ingrannes et de Lorris
France Iles Cerbicale
France Forêts domaniales de Corse
France Vallée d'Asco
France Vallée de la Restonica
France Iles Sanguinaires
France Parc National des Cévennes
France Gorges du Tarn et de la Jonte
France Iles d'Hyères
France Plateau de l'Arbois, garrigues de Lancon et chaîne des Côtes
France Region de Pressac, étang de Combourg
France Marais et forêt d'Olonne
France Forêt du Gavre
France Basse Ardêche
Italy Peloritani mountains
Italy Finalese
Italy Asinara island, Piana island and Stintino peninsula
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 (2023) Species factsheet: Curruca undata. Downloaded from http://www.birdlife.org on 20/03/2023. Recommended citation for factsheets for more than one species: BirdLife International (2023) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 20/03/2023.