SEEN - SE European Bird Migration Network
Autumn migration and moult strategy of the Sedge Warbler (Acrocephalus schoenobaenus) at Burullus (northern Egypt)

Oksana Zakala1, Wed Ibrahim2, Przemysław Busse3

1 Zoological Museum, Lviv University, Lviv, Ukraine
2 Wadi El Rayan Protected Area, Fayoum, Egypt
3 Bird Migration Research Station, University of Gdańsk, Poland

The SEEN (SE European Bird Migration Network) ringing station at Burullus (31°22'N, 30°15'E; Egypt) has been working from 1 September to 2 November 2005. The station is situated at the southern border of a huge reedbed area of the Burullus Lagoon. During the work altogether 443 Sedge Warblers were caught with mist-nets, and processed: ringed, measured, scored for fat deposit and tested for directional preferences. Among caught birds – 209 were adults and 234 were immatures. 16 adult individuals were caught at least twice while 18 immatures were retrapped. The migration dynamics patterns of adults and immatures differed very much: median passage date for adults was 6–7 September, while for immatures 1–2 October. The stop-over strategies of adults and immatures were also different: despite a number of short-time retraps (below 7 days) was similar and found as 3.3% of adults and 3.8% of immatures (fat score dropped during this stay by 0.67 in adults and by 0.37 in immatures), another 3.0% of immatures performed stop-over for medium length stay (7–17 days) and they gained an average fat score of 1.22, while no adult bird was noted in this group. In contrary a long-term stop-over (more than 20, up to 57 days) was noted in adults only. This last group of birds is composed of adults that performed a complete moult in Burullus and that lost on average 1.3 fat scores in this time. The complete moult of adult Sedge Warblers was not reported from areas north of the Sahara while in Burullus around 10% of adults caught were found moulting primaries up to completing a new plumage (moult score 50). For some individuals subsequent moult scorings are available and these illustrate a course of the moult performed.

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