Callum Macgregor

Small warbler, feeds on insects and spiders; in autumn also berries. Nominate trochilus: W Europe to S Poland and Romania; acredula: Scandinavia to Siberia (Yenisey River); yakutensis: E Siberia (Taymyr Peninsula to Anadyr River). Unlike similar Chiffchaff P. collybita, extends widely into arctic but only marginally into Mediterranean region. Differs in being a bird less of mature woodland than of scrub, second growth, and transitions to more open habitats. Although the population is decreasing, the population is large enough to assign the status of Least Concern. All populations migratory, wintering extensively in sub-Saharan Africa from S Sénégal east to Ethiopia, south to South Africa.

Season of assessment

B

Population trendDecreasing
Population size
(min-max, best estimate)		106000000-161000000,130000000
Red List categoryLC
Franks, S., Fiedler, W., Arizaga, J., Jiguet, F., Nikolov, B., van der Jeugd, Ambrosini, R, Aizpurua, O., Bairlein, F., Clark, J., Fattorini, N, Hammond, M., Higgins, D, Levering, H., Skellorn, W., Spina, F, Thorup, K. Walker, J., Woodward, I. and Baillie, S.R. (1) (2022) Online Atlas of the movements of European bird populations. https://migrationatlas.org EURING/CMS (1) Principal investigator
Map

Overall Connectivity for Willow Warbler

S. Fennoscandian birds allegedly belonging to trochilus move NE - SW: recoveries in W and SW Europe, S UK and W Africa; alledged acredula move N - S: recoveries in C Europe, Italy and C Africa; and NW – SE to E and SE Europe, Turkey, Near East, Egypt and E Africa. Migratory divide across central Scandinavia diffuse and genetic differentiation is small (Bensch et al. 1999). Few birds move E - W, found in Iceland, Shetlands and Faroer. From UK and Ireland birds move NNW - SSE, found W Europe, Iberia and W Africa. Birds from W Europe mainly move NE - SW, recoveries in Iberia and W Africa; a minority move NNW - SSE, recoveries C Europe, Italy, E Algeria, Tunesia and C Africa. Birds from C and E Europe show directions from NE - SW to NW – SE, but from C Europe there are only recoveries in W Africa and from E Europe only in E Africa.

Recoveries by Condition for Willow Warbler

Until 1960 52% of the recoveries were dead birds: 8% were shot and 2,8% intentionally taken. From 1961 to 1990 11% concerned dead birds: 1% was shot and 0,4% was intentionally taken. From 1991 almost all recoveries concerned alive birds. Most dead birds were intentionally taken or shot in Portugal, N Spain and N Italy; also around the Mediaranean E coast and in NW, W, C and SE Africa.

Annual Movements for Willow Warbler

In Nov - Feb birds are found in W, C and SE Africa, but also in Europe and NW Africa. In Mar numbers in NW Africa and Europe increase. In Apr hotspots are in the UK, the Low Countries and C Europe, also many birds in S Europe and NW Africa and first birds in S Fennoscandia; there are still birds in W and SE Africa and in Near East. In May - Jul most birds are in the UK, NW Europe and S Fennoscandia; less birds in N Fennoscandia and S Europe. In Aug - Sep numbers in SW Europe and N Italy increase, first birds in NW Africa, SE Europe, Near East and Egypt. In Oct numbers most birds have left Fennoscandia, still birds in Europe, most in the Low Countries, N Italy, Portugal and Spain; also in NW Africa, Egypt and Near East; first birds in W, C and SE Africa.

Connectivity by Month by Region for Willow Warbler

Fennoscandian birds are found in W Europe (Aug - Sep, Apr), SW Europe (Sep - Nov), E Spain, the Balearic Isles and S France (Apr - May), N Italy (Sep - Dec), S Italy (Apr - May), NW Africa (Sep - Dec, Mar - May), C and SE Europe, N Egypt (Sep - Oct), Near East (Sep - Oct, Feb - May) and in whole sub-Saharan Africa (Oct - Apr). Ireland and UK birds are found in SW Europe (Sep - Dec), E Spain and France (Feb - Apr), Switzerland (Apr), NW Africa (Sep - Oct, Mar - Apr) and W Africa (Oct - Apr). W Europe birds are found in Portugal and (W) Spain (Aug - Nov), E Spain, S France and Italy (Mar - May), NW Africa (Sep - May) and C Africa (Oct - Mar). Birds of C and E Europe are found in SW Europe (Aug - Oct), S Europe (Apr - May), NW Africa (Oct - Dec, Apr -May), W Africa (Mar - Apr).

Henk van der Jeugd

References

Statistics Map
N records N individuals N recoveries
Mapped data*
Total available data
*Mapped data include only distant (>= 50 km) recoveries
References Map
Bensch, S., Andersson, T., Åkesson, S.1999 . Morphological and molecular variation across a migratory divide in willow warblers, Phylloscopus trochilus. Evolution 53 Link to Article (DOI: https://doi.org/10.1111/j.1558-5646.1999.tb04573.x) : 1925–1935

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