Journal of Ornithology

, Volume 152, Supplement 1, pp 129–140 | Cite as

Distribution, ecology and threat status of the Aquatic Warblers Acrocephalus paludicola wintering in West Africa

  • Martin Flade
  • Ibrahima Diop
  • Martin Haase
  • Arnaud Le Nevé
  • Steffen Oppel
  • Cosima Tegetmeyer
  • Anna Vogel
  • Volker Salewski
Original Article

Abstract

The Aquatic Warbler Acrocephalus paludicola (AW) is the only globally threatened passerine species of continental Europe. The global population decreased by >90% during the 20th century. AWs breed in Palaearctic fen mires and sedge meadows and spend the non-breeding season in sub-Saharan Africa, but until 2007 no regular wintering site had been identified. To date, the only wintering grounds that have been discovered are in river floodplain marshes along the Senegal River in the Djoudj area, Senegal. Searches for additional wintering sites in south-western Mauritania, northern Senegal and Gambia have been unsuccessful. In Djoudj, AWs are found in extensive marshes dominated by Scirpus spp. or Sporobolus robustus, and favour shallow water and the occurrence of Eleocharis mutata and Sporobolus robustus on the microhabitat scale. Within these marshes, however, AW appear to avoid dense homogenous stands dominated by Scirpus maritimus. Estimates of the density of wintering AWs in suitable habitats range between 0.5 and 1.6 birds/ha. According to the estimated area of suitable habitat (4,000–10,000 ha with strong seasonal and inter-annual fluctuations), the Djoudj area may hold between 10 and >50% of the global population during the non-breeding season. Ringing, molecular studies and feather isotope ratios have failed to provide conclusive evidence for connectivity between the Djoudj area and particular Palaearctic breeding populations. Based on winter records, habitat data and satellite images, we speculate that the Inner Niger Delta in Mali could be another important wintering area. A pilot project that equipped 30 AWs in the Ukraine with geolocators in 2010 may reveal more details about migration routes and lead to the discovery of currently unknown wintering sites.

Keywords

Long-distance migrants Wintering grounds Moulting sites Senegal Connectivity Globally threatened species 

Notes

Acknowledgements

In addition to most of the authors, the following European AWCT members participated in the field work in Africa: Viktar Fenchuk (Belarus); Norbert Roothaert (Belgium); Bruno Bargain and Gaétan Guyot (France); Sven Baumung, Peter Becker, Stefan Bräger, Alex Eilers, Benedikt Gießing, Angela Helmecke, Britta Kiesewetter, Vera Knöfler, Wolfgang Mädlow, Torsten Ryslavy, Klemens Steiof and Franziska Tanneberger (Germany); Zsolt Végváry (Hungary); Oskars Keiss (Latvia); Zydrunas Preiksa (Lithuania); Grzegorz Kiljan and Janusz Kloskowski (Poland); Julio Manuel Neto (Portugal); Carlos Zumalacareggui Martínez (Spain); Anatoly Poluda (Ukraine); Lars Lachmann (UK). We are grateful to the Djoudj and Diawling National Park staff who made our stay a pleasure there. In particular, we thank senior ornithologist I. Bindia (Djoudj), Dr. Z. El Abidine Ould Sidaty (Diawling) and M. Ould Daddah (Diawling) for their patience, assistance and helpful advice. Bird ringing was supported by Bretagne Vivante and the French Bird Ringing Centre (Museum Paris). S. Winter gave invaluable assistance with the statistical analyses. We are also very grateful to Paul Donald for critical comments and final English editing of the text. For financial support we express our sincere thanks to the RSPB, BirdLife International partner in the UK, the Stresemann Fund of the German Ornithological Society, the O M H Schmidt-Felsche Foundation and The Wetland Trust (S. Rumsey). We are also grateful to N. Schäffer (RSPB), L. Glowka (CMS Secretariat) and E.W. Blencowe (Department of Environment, Food and Rural Affairs of the UK, DEFRA) for their support. The participation of V. Fenchuk was supported by the Michael Otto Foundation for Environmental Protection, the participation of O. Keiss was financed by the European Social Fund grant to the University of Latvia. The participation of C. Tegetmeyer and her PhD project are supported by the Deutsche Bundesstiftung Umwelt (DBU) and the MAVA Foundation.

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Copyright information

© Dt. Ornithologen-Gesellschaft e.V. 2011

Authors and Affiliations

  • Martin Flade
    • 1
  • Ibrahima Diop
    • 2
  • Martin Haase
    • 3
  • Arnaud Le Nevé
    • 4
  • Steffen Oppel
    • 5
  • Cosima Tegetmeyer
    • 6
  • Anna Vogel
    • 3
  • Volker Salewski
    • 7
  1. 1.Abt. Großschutzgebiete und RegionalentwicklungLandesamt für Umwelt, Gesundheit und Verbraucherschutz BrandenburgEberswaldeGermany
  2. 2.Station Biologique, Point Focal de la Réserve de Biosphère Transfrontière du Delta du Fleuve SénégalSt LouisSenegal
  3. 3.Vogelwarte Hiddensee, Zoologisches Institut und MuseumUniversität GreifswaldGreifswaldGermany
  4. 4.Société pour l’Étude et la Protection de la Nature en Bretagne (SEPNB)Bretagne VivanteBrest cedex 3France
  5. 5.Royal Society for the Protection of Birds (RSPB) SandyUK
  6. 6.Institut für Botanik und LandschaftsökologieUniversität GreifswaldGreifswaldGermany
  7. 7.Behavioural BiologyUniversity of OsnabrückOsnabrückGermany

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