Scott Mayson

Breeds at middle latitudes from W Europe to Mongolia, avoiding the boreal region, main mountain ranges and very dry areas. Overwinters scattered in W Africa and the Indian subcontinent (BirdLife International 2021).

Season of assessment

B

Population trendDecreasing
Population size
(min-max, best estimate)		1270000-2250000,1660000
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 Common Grasshopper Warbler

Recoveries from European population show a clear, main migratory axis NE-SW, passing through Iberia and the W Mediterranean up to W Africa (from Mauritania to Gambia). Recoveries show high overlap between ringing regions, suggesting weak connectivity, since all birds seem to behave as belonging to a population that uses a shared migratory flyway.

Recoveries by Condition for Common Grasshopper Warbler

Most recoveries (97%) due to birds recaptured alive (ringing recovery). Extremely few recoveries (N=3) before 1960.

Annual Movements for Common Grasshopper Warbler

Breeding quarters in Europe left probably from Jul, with SW-movement patent in Aug. NW Africa is reached in Aug-Sep, and recoveries in W Africa mostly obtained in Jan. Departure from winter quarters in Jan, then birds seem to stop over up to 2 months somewhere in N Africa (Bayly et al. 2011).

Connectivity by Month by Region for Common Grasshopper Warbler

Autumn migration patent in Aug, with movements to SW obvious across Europe. Recoveries from northern warblers in Iberia mostly in Sep-Oct. Passage across NW Africa (Morocco) also Sep-Oct (though note the few recoveries existing for the region). Ringing studies suggest that <10% of birds in Portugal may reach sub-Saharan grounds without refueling (Bayly et al. 2011), highlighting the importance of NW Africa as a main stopover region before crossing the Sahara in autumn. Wintering in W Africa (Mauritania, Senegambia) at least until Jan. Recoveries suggest a further-E flyway in spring, with more recoveries in the Mediterranean and less in Iberia (where, in addition, all are found along the Mediterranean façade, none in W Iberia), indicating a possible loop migration.

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
Bayly, N. J., Rumsey, S. J. R., Clark, J. A.2011 . Crossing the Sahara desert: migratory strategies of the Grasshopper Warbler Locustella naevia. Journal of Ornithology 152
BirdLife International2021 . Species factsheet: Locustella naevia.

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