Aron Tanti

Breeds scattered within the circum-Mediterranean region, up to C Asia (farther E than Aral Sea), reaching the Persian Gulf. Some colonies also in W Africa (BirdLife International 2021). Mostly migratory, though birds remain in/close to their breeding areas in winter (Olsen & Larsson 2004).

Season of assessment

B

Population trendDecreasing
Population size
(min-max, best estimate)		61100-73200,66300
Red List categoryVU
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 Slender-billed Gull

Birds from SW Iberia winter mostly in NW Africa (up to Gambia), while birds from SE/E Iberia or S France move primarily to C/E Mediterranean (many recoveries in Sardinia, Algeria and Tunisia). Italian population migrates S in winter (again many birds wintering in Tunisia), whilst Italy and the C Mediterranean receives in winter many birds from the Black Sea. Birds from this last origin region overwinter mainly in the C/E Mediterranean. Birds breeding E to the Black Sea area overwinter S of the Caspian Sea and the Arabian region. Recoveries from summer to summer show high breeding/natal dispersal rate.

Recoveries by Condition for Slender-billed Gull

Overall, most recoveries (58%) due to birds seen alive, identified by other means (from these most from leg ring(s)). Shots represent a small fraction (7.2%). By periods, however, the proportion of birds found dead by shooting passed from 38% before 1960 to 1.8% from 1991 to present. Nowadays, most recoveries (68%) come from birds seen alive thanks to colour-ring projects in several colonies through the species’ distribution range.

Annual Movements for Slender-billed Gull

Leaves breeding quarters in Jul. Recoveries in winter quarters mostly from Oct to Mar, though some birds already reach these areas in Aug, and remain there until Apr. Spring migration takes place from Feb to May.

Connectivity by Month by Region for Slender-billed Gull

Similar temporal patterns between regions, so see ‘Annual movements’.

Juan Arizaga

References

Statistics Map
N records N individuals N recoveries
Mapped data*
Total available data
*Mapped data include only distant (>= 50 km) recoveries
References Map
BirdLife International2021 . Species factsheet: Larus genei.
Olsen, K. M., Larsson, H.2004 . Gulls of Europe, Asia and North America. Helm Identification Guides, London

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