Phylloscopus trochilus 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Aves Passeriformes Phylloscopidae

Scientific Name: Phylloscopus trochilus (Linnaeus, 1758)
Regional Assessments:
Common Name(s):
English Willow Warbler
French Pouillot fitis
Taxonomic Source(s): AERC TAC. 2003. AERC TAC Checklist of bird taxa occurring in Western Palearctic region, 15th Draft. Available at: # _the_WP15.xls#.

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2016
Date Assessed: 2016-10-01
Assessor(s): BirdLife International
Reviewer(s): Butchart, S. & Symes, A.
Facilitator/Compiler(s): Ashpole, J, Butchart, S., Ekstrom, J.
This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). 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). The population size is extremely large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
Previously published Red List assessments:

Geographic Range [top]

Countries occurrence:
Albania; Algeria; Andorra; Angola; Armenia; Austria; Azerbaijan; Bahrain; Belarus; Belgium; Benin; Bosnia and Herzegovina; Botswana; Bulgaria; Burkina Faso; Burundi; Cameroon; Cape Verde; Central African Republic; Chad; Congo; Congo, The Democratic Republic of the; Côte d'Ivoire; Croatia; Cyprus; Czech Republic; Denmark; Djibouti; Egypt; Equatorial Guinea; Eritrea; Estonia; Ethiopia; Faroe Islands; Finland; France; Gabon; Gambia; Georgia; Germany; Ghana; Gibraltar; Greece; Guinea; Guinea-Bissau; Hungary; Iceland; Iran, Islamic Republic of; Iraq; Ireland; Israel; Italy; Jordan; Kazakhstan; Kenya; Kuwait; Latvia; Lebanon; Lesotho; Liberia; Libya; Liechtenstein; Lithuania; Luxembourg; Macedonia, the former Yugoslav Republic of; Malawi; Mali; Malta; Mauritania; Moldova; Monaco; Montenegro; Morocco; Mozambique; Namibia; Netherlands; Niger; Nigeria; Norway; Oman; Poland; Portugal; Qatar; Romania; Russian Federation (Central Asian Russia, Eastern Asian Russia, European Russia); Rwanda; Saudi Arabia; Senegal; Serbia; Sierra Leone; Slovakia; Slovenia; Somalia; South Africa; South Sudan; Spain; Sudan; Swaziland; Sweden; Switzerland; Syrian Arab Republic; Tajikistan; Tanzania, United Republic of; Togo; Tunisia; Turkey; Turkmenistan; Uganda; Ukraine; United Arab Emirates; United Kingdom; Western Sahara; Yemen; Zambia; Zimbabwe
Canada; Comoros; Greenland; India; Japan; Saint Helena, Ascension and Tristan da Cunha; Seychelles; Svalbard and Jan Mayen
Present - origin uncertain:
Additional data:
Continuing decline in area of occupancy (AOO):Unknown
Extreme fluctuations in area of occupancy (AOO):NoEstimated extent of occurrence (EOO) - km2:22200000
Continuing decline in extent of occurrence (EOO):UnknownExtreme fluctuations in extent of occurrence (EOO):No
Continuing decline in number of locations:Unknown
Extreme fluctuations in the number of locations:No
Upper elevation limit (metres):1000
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:In Europe, the breeding population is estimated to number 62,200,000-97,100,000 pairs, which equates to 124,000,000-194,000,000 mature individuals (BirdLife International 2015). Europe forms c.30% of the global range, so a very preliminary estimate of the global population size is 413,000,000-647,000,000 mature individuals, although further validation of this estimate is needed. The population in Russia has been estimated at < c.100,000 breeding pairs and < c.1,000 individuals on migration (Brazil 2009).

Trend Justification:  In Europe, trends between 1980 and 2013 show that populations have undergone a moderate decline (EBCC 2015).
Current Population Trend:Decreasing
Additional data:
Number of mature individuals:400000000-649999999Continuing decline of mature individuals:Unknown
Extreme fluctuations:NoPopulation severely fragmented:No
Continuing decline in subpopulations:Unknown
Extreme fluctuations in subpopulations:NoAll individuals in one subpopulation:No

Habitat and Ecology [top]

Habitat and Ecology:During the breeding season this species inhabits deciduous and mixed forests in which birch (Betula) largely predominates, but also birches and willow (Salix) thickets and scrub on arctic tundra. In central areas it is found in temperate heathland, forest clearings, damp areas with alders (Alnus) and willows 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, moss, strips of bark, animal 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).
Systems:Terrestrial; Freshwater
Continuing decline in area, extent and/or quality of habitat:Unknown
Generation Length (years):3.5
Movement patterns:Full Migrant

Threats [top]

Major Threat(s): 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).

Conservation Actions [top]

Conservation Actions: Conservation Actions Underway
CMS Appendix II. Bern Convention Appendix II. There are currently no known conservation measures for this species within Europe.

Conservation Actions Proposed

This species would benefit from the preservation and restoration of its woodland habitat, including the maintenance of traditional management techniques.

Citation: BirdLife International. 2016. Phylloscopus trochilus. The IUCN Red List of Threatened Species 2016: e.T22715240A87636348. . Downloaded on 21 September 2018.
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