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Dartford Warbler Sylvia undata

Justification
This species is declining at a moderately rapid rate, qualifying the species as Near Threatened. Declines in the core population in Spain are largely responsible for overall declines. The drivers of this decline are not entirely clear but include habitat degradation and modification. Should the population be found to be declining more rapidly, the species would warrant uplisting to a higher threat category.

Taxonomic source(s)
AERC TAC. 2003. AERC TAC Checklist of bird taxa occurring in Western Palearctic region, 15th Draft. Available at: #http://www.aerc.eu/DOCS/Bird_taxa_of _the_WP15.xls#.
Cramp, S.; Perrins, C. M. 1977-1994. Handbook of the birds of Europe, the Middle East and Africa. The birds of the western Palearctic. Oxford University Press, Oxford.

Taxonomic note

Distribution and population
Sylvia undata is restricted to southern and western Europe and north-west Africa, where it is patchily distributed but locally common to very common in Spain (including Balearic Islands), Portugal, Andorra, Morocco. Algeria, Tunisia, France (including Corsica), United Kingdom and Italy (including Sardinia) (del Hoyo et al. 2006). The European breeding population, which constitutes more than 95% of the global population, underwent a large decline during 1970-1990 (Tucker and Heath 1994). The stronghold is located in Spain which holds 983,000-1,750,000 pairs (V. Escandell in litt. 2009), but the population here decreased by 4.6 % per year between 1998-2011 (V. Escandell in litt. 2012). France holds the next largest population (150,000-600,000 pairs) but the trend here is unclear. Trends are unknown in Portugal (10,000-100,000 pairs), Italy (10,000-30,000 pairs) and Andorra (c.20-30 pairs) (BirdLife International 2004). In the UK it has recently increased rapidly and extended its range northwards, reaching a total of 3,214 territories in 2006 (Wotton et al. 2009). If trends in Spain are reflected elsewhere in Europe, the European breeding population may have declined nearly 30% over the last 12.3 years (three generations).

Population justification
In Europe (which covers more than 95% of the breeding range), the breeding population is estimated to be 1.1-2.5 million breeding pairs, based on 983,000-1,750,000 pairs in Spain (V. Escandell in litt. 2009), 150,000-600,000 pairs in France, 10,000-100,000 pairs in Portugal, 10,000-30,000 pairs in Italy, c.20-30 pairs in Andorra (BirdLife International 2004) and 3,214 territories in France (Wotton et al. 2009). This equates to 3.3-7.5 million individuals.

Trend justification
Data from the Spanish common bird monitoring scheme (SACRE) suggest that the species may have declined by an average of 4.6% (95% CI: 6.2-3.1) per year during 1998-2011 (V. Escandell in litt. 2012), with declines occurring in all regions (and hence not simply attributable to a northwards shift in the species's range, as predicted under climate change scenarios). If one assumes that other national trends have remained constant since 2000, the European breeding population may have declined by nearly 30% over the last 12 years (three generations). The population trend for the species produced by the Pan-European Common Bird Monitoring Scheme suggests that it declined by 27% during 1990-2005 (PECBMS in press). In Europe, trends since 1996 show that populations have undergone a moderate decline (p<0.01), based on provisional data for 21 countries from the Pan-European Common Bird Monitoring Scheme (EBCC/RSPB/BirdLife/Statistics Netherlands; P. Vorisek in litt. 2008).

Ecology
It favours dense, homogeneous scrub, garrigue and low maquis c.0.5-1.5 m in height and dominated by species such as Ulex, Erica, Rosmarinus, Genista, Cistus and Quercus coccifera (del Hoyo et al. 2006). It is largely sedentary but undertakes some short-distance dispersive movements and some European birds spend the non-breeding season in north-west Africa (del Hoyo et al. 2006). It is primarily a lowland species in the north of its range but occurs to 1,800-2,000 m in the Pyrenees and north-west Africa (del Hoyo et al. 2006).

Threats
Reasons for the recent Spanish decline are still unclear. It is vulnerable to severe winters, particularly in the northern part of its range (del Hoyo et al. 2006). Cold spells in December 2001 and the winter of 2004-2005 caused high mortality in Spain (J. J. R. Encalado in litt. 2007), while the UK population was reduced to 11 pairs after the severe winter of 1962-1963 (del Hoyo et al. 2006). Increasing densities of cattle on the Spanish dehesa are causing severe habitat degradation through overgrazing (J. J. R. Encalado in litt. 2007), which may be affecting the species. Afforestation has decreased the amount of suitable habitat in parts of France and Iberia (Shirihai et al. 2001). Changes in the pattern and frequency of wildfires may be a threat, although the species often colonises early successional habitat created by such fires (del Hoyo et al. 2006). Postfire forest management can negatively affect the species through the removal of burnt trees as the species has been shown to favour a moderate coverage of logging remnants after fires (Herrando et al. 2009).


Conservation Actions Underway
Population trends are monitored in parts of the species's range and it occurs in a number of protected areas. Conservation Actions Proposed
Carry out specific research on drivers of declines, particularly the link with habitats. Research trends elsewhere within its range, particularly France and North Africa. Develop programmes which subsidise farming practices which promote healthy populations of the species.

References
BirdLife International. 2004. Birds in Europe: population estimates, trends and conservation status. BirdLife International, Cambridge, U.K.

del Hoyo, J.; Elliott, A.; Christie, D. 2006. Handbook of the Birds of the World, vol. 11: Old World Flycatchers to Old World Warblers. Lynx Edicions, Barcelona, Spain.

Escandell, V. 2007. SEO, Madrid, Spain.

Herrando, S.; Brotons, L.; Guallar, S.; Sales, S.; Pons, P. 2009. Postfire forest management and Mediterranean birds: the importance of the logging remnants. Biodiversity and Conservation 18(8): 2153-2164.

Shirihai, H.; Gargallo, G.; Helbig, A. J. 2001. Sylvia warblers: identification, taxonomy and phylogeny of the genus Sylvia. Helm, London.

Tucker, G. M.; Heath, M. F. 1994. Birds in Europe: their conservation status. BirdLife International, Cambridge, U.K.

Wotton, S.; Conway, G.; Eaton, M.; Henderson, I.; Grice, P. 2009. The status of the Dartford Warbler in the UK and Channel Islands in 2006. British Birds 102: 230-246.

Further web sources of information
Detailed species account from Birds in Europe: population estimates trends and conservation status (BirdLife International 2004)

Detailed species account from Birds in Europe: population estimates, trends and conservation status (BirdLife International 2004)

Explore HBW Alive for further information on this species

Search for photos and videos, and hear sounds of this species from the Internet Bird Collection

Text account compilers
Butchart, S., Derhé, M., Ekstrom, J., Mahood, S., Symes, A., Taylor, J.

Contributors
Encalado, J., Escandell, V., Herrando, S., Iñigo, A., Wotton, S.

IUCN Red List evaluators
Butchart, S., Symes, A.

Recommended citation
BirdLife International (2014) Species factsheet: Sylvia undata. Downloaded from http://www.birdlife.org on 18/12/2014. Recommended citation for factsheets for more than one species: BirdLife International (2014) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 18/12/2014.

This information is based upon, and updates, the information published in BirdLife International (2000) Threatened birds of the world. Barcelona and Cambridge, UK: Lynx Edicions and BirdLife International, BirdLife International (2004) Threatened birds of the world 2004 CD-ROM and BirdLife International (2008) Threatened birds of the world 2008 CD-ROM. These sources provide the information for species accounts for the birds on the IUCN Red List.

To provide new information to update this factsheet or to correct any errors, please email BirdLife

To contribute to discussions on the evaluation of the IUCN Red List status of Globally Threatened Birds, please visit BirdLife's Globally Threatened Bird Forums.

Additional resources for this species

ARKive species - Dartford warbler (Sylvia undata) 0

Key facts
Current IUCN Red List category Near Threatened
Family Sylviidae (Old World warblers)
Species name author (Boddaert, 1783)
Population size mature individuals
Population trend Decreasing
Distribution size (breeding/resident) 835,000 km2
Country endemic? No
Links to further information
- Additional Information on this species