Phylloscopus trochilus -- (Linnaeus, 1758) ANIMALIA -- CHORDATA -- AVES -- PASSERIFORMES -- Common names: Warbler; Pouillot fitis European Red List Assessment European Red List Status LC -- Least Concern, (IUCN version 3.1) Assessment Information Year published: 2015 Date assessed: 2015-03-31 Assessor(s): BirdLife International Reviewer(s): Symes, A. Compiler(s): Ashpole, J., Burfield, I., Ieronymidou, C., Pople, R., Wheatley, H. & Wright, L. Assessment Rationale European regional assessment: Least Concern (LC) EU27 regional assessment: Least Concern (LC)

At both European and EU27 scales this has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence 10% in ten years or three generations, or with a specified population structure). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (30% decline over ten years or three generations).

For these reasons the species is evaluated as Least Concern within both Europe and the EU27. Occurrence Countries/Territories of Occurrence Native: Albania; Andorra; Armenia; Austria; Azerbaijan; Belarus; Belgium; Bosnia and Herzegovina; Bulgaria; Croatia; Cyprus; Czech Republic; Denmark; Faroe Islands (to DK); Estonia; Finland; France; Georgia; Germany; Greece; Hungary; Iceland; Ireland, Rep. of; Italy; Latvia; Liechtenstein; Lithuania; Luxembourg; Macedonia, the former Yugoslav Republic of; Malta; Moldova; Montenegro; Netherlands; Norway; Poland; Portugal; Romania; Russian Federation; Serbia; Slovakia; Slovenia; Spain; Sweden; Switzerland; Turkey; Ukraine; United Kingdom; Gibraltar (to UK) Vagrant: Greenland (to DK); Svalbard and Jan Mayen (to NO) Population The European population is estimated at 62,200,000-97,100,000 pairs, which equates to 124,000,000-194,000,000 mature individuals. The population in the EU27 is estimated at 24,900,000-43,700,000 pairs, which equates to 49,700,000-87,500,000 mature individuals. For details of national estimates, see Supplementary PDF. Trend In Europe and the EU27 the population size is estimated to be decreasing by less than 25% in 10.5 years (three generations). For details of national estimates, see Supplementary PDF. Habitats and Ecology During the breeding season this species inhabits deciduous and mixed forests in which (Betula) largely predominates, but also and willow (Salix) thickets and scrub on arctic tundra. In central areas it is found in temperate heathland, forest clearings, damp areas with (Alnus) and as well as secondary growth, scrub and shrubby areas away from trees. It generally uses a wide selection of locations, including large overgrown gardens, orchards, hedges, railway embankments, and rough pastures with tussock grassland. It breeds from April to July and lays four to eight eggs. The nest is a ball of dry grasses, leaves, plant fibres, , strips of bark, hair and feathers and is placed on the ground, usually well concealed in vegetation. It feeds mainly on insects and their eggs and larvae and some plant material. The species is migratory and winters in Africa, south of the Sahara (Clement 2006). Habitats & Altitude Habitat (level 1 - level 2) Importance Occurrence Artificial/Terrestrial - Arable Land suitable breeding Artificial/Terrestrial - Pastureland suitable breeding Artificial/Terrestrial - Rural Gardens major breeding Forest - Boreal suitable breeding Forest - Temperate major breeding Altitude max. 1000 m Occasional altitudinal limits Threats The species is affected by drought conditions in its wintering quarters and habitat alterations due to human population expansion (Thingstad et al. 2014). In the southern U.K., habitat loss linked to modern forest management techniques that alter the woodland vegetation structure is likely to have caused declines (Stostad and Menéndez 2014). In addition, declining oak tree health may have impacted the species as oak is typically a major source of invertebrates (Peach et al. 1995). Threats & Impacts Threat (level 1) Threat (level 2) Impact and Stresses Agriculture & Agro-industry Timing Scope Severity Impact aquaculture plantations Ongoing Minority (<50%) Slow, Significant Low Impact Declines Stresses Ecosystem conversion; Ecosystem degradation Climate change & Droughts Timing Scope Severity Impact severe weather Ongoing Majority (50-90%) Slow, Significant Medium Impact Declines Stresses Species mortality Conservation Conservation Actions Underway CMS Appendix II. Bern Convention Appendix II. There are currently no known conservation measures for this species.

Conservation Actions Proposed This species would benefit the preservation and restoration of its woodland habitat, including the maintenance of traditional management techniques. Bibliography Clement, P. 2006. Willow Warbler (Phylloscopus trochilus). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. and de Juana, E. (eds.) 2014. Handbook of the of the World Alive. Lynx Edicions, Barcelona. (retrieved from http://www.hbw.com/node/58860 on 26 March 2015). Peach, W.J., Crick, H.Q.P. and Marchant, J.H. 1995. The demography of the decline in the British willow warbler population. Journal of Applied Statistics, 22(5&6): 905-922. Stostad, H.N. and Menéndez, R. 2014. Woodland structure, rather than tree identity, determines the breeding habitat of Willow Warblers Phylloscopus trochilus in the northwest of England. Study, 61(2), 246-254. Thingstad, P.G., Hogstad, O. and Speed, J.D. 2014. The influence of climatic conditions in breeding grounds and migratory flyways on a subalpine Norwegian Willow Warbler Phylloscopus trochilus population. Ornis Fennica, 91, 00-00. Map (see overleaf)