Background The aquatic warbler (Acrocephalus paludicola) is by far the rarest European warbler. Its breeding population, estimated at 12 500-20 000 individuals, is mainly distributed over Poland and Belarus. The species's wintering zone is not very well known, but appears to be mostly in western tropical Africa. In recent decades research has revealed that the main stopover and fattening areas during the post-breeding migration are located in north-western France, along the Channel coast, and further down, along the Atlantic coast. This region is characterised by a string of coastal marshes which are currently suffering from a lack of adequate management. This is further aggravated by the secretiveness of this little warbler and the lack of knowledge on behalf of site managers about its ecological requirements. Changes to wetland zones (such as the degradation of hydrological functioning, natural filling-up, water pollution, and man-made changes) have also reduced the biodiversity of France's coastal marshes, causing a decline in their ecological value as a feeding and resting habitat for the aquatic warbler. Objectives The main objective of this LIFE project was to increase the area of favourable habitat for migrating aquatic warblers in the Atlantic coastal marshes of France. Two specific aims of the project were: 1)The ecological maintenance or rehabilitation of three important stopover marshes in Brittany, all known to be important staging areas for aquatic warblers; and 2)The promotion of the management know-how acquired during the project. Further project actions would include: Improving knowledge about the species and its habitat through radio-tracking; Carrying out an inventory of additional spring migratory stopover sites; Protecting the most important stopovers by controlling management and property status on 30 ha, through management agreements or land purchase; Managing 265 ha of marshes to transform them into optimal warbler habitats; this management will consist in rehabilitation - clearing out, digging ditches, installing gates - maintenance work and management of water levels; Promoting the importance of these zones among the local population (through films, meetings, brochures and activities for the general public and schoolchildren); and Organising technical workshops and publishing the management know-how gained.Results The project acquired 39.5 ha of marshes that are favourable to the aquatic warbler, exceeding the initial objective of 10 ha, and a further 13.4 ha were purcahsed using other funding. Moreover agreements were signed or are in negotation with the landowners of two sites so as to ensure that a management in favour of the aquatic warbler will be carried out in the long-term. The project restored habitats (wetlands, reed beds) that contribute to the conservation of the aquatic warbler and can benefit other species, such as the European otter, great bittern, water vole and nesting bird species. This was done through: Hydraulic works and equipments (floodgates) that allow for the flooding of a total of 270 ha over the three project sites; Repetitive reed bed cutting to restore 47 ha of wet meadows; Installation of fences along 2.8 km of land plots to avoid human disturbance and allow grazing to take place; Clearing of invasive plant species (Pampas grass, Baccharis, Japanese knotweed, willows) spread out over 30 ha on each of the three sites.A suitable management strategy was subsequently set up, ensuring the apropraite regulation of water levels (high during the winter period and lower in the summer). This management will be continued by the beneficiary after the end of the project. The LIFE project has improved knowledge of the aquatic warbler and its stopover habitats, which will help to ensure better management of sites. A radio-tracking operation was carried out to improve the knowledge of the habitat selection on a major stop-over site for the species in France, and 13 other sites that are potentially used as stopover points were studied by ringing. These sites could then be prioritised according to their significance for the species. Based on these results, the beneficiary developed a regional strategy for the conservation of the aquatic warbler as a tool for decision-making. An aquatic warbler wintering site was discovered in Senegal, thanks to an expedition involving the LIFE project team as well as experts from other countries. The project developed and widely distributed a technical guidebook to help site managers implement measures that benefit the aquatic warbler. Its recommendations can be applied on the 200 stopover sites that were identified in France, as well as those in other countries. The French Ministry of Ecology has asked the project beneficiary to produce a National Action Plan for the species for the period 2010-2014. The beneficiary believes that the ministry's decision to launch such an action plan is a direct consequence of the LIFE project. The project contributed to the development of action plans ("Document d'Objectifs") for the three Natura 2000 sites. These include funding to continue some of the LIFE project's tasks. A significant campaign was carried out to raise awareness among local inhabitants, schoolchildren and other stakeholders. The project developed many tools and documents and organised a large number of activities and events. Some 1 400 schoolchildren and 1 800 members of the general public learned about the species and its conservation. A movie was produced, which was awarded the "Prix du parc interrégional du Marais Poitevin" during the 23rd bird film festival in Ménigoute, France (November 2007). A final seminar was organised with 80 participants, including 20 experts working on the conservation of aquatic warbler in other countries. The seminar published a set of high-quality proceedings as an outcome. The project video and many of their documents can be found in the "read more" section below, as well as further information on the project (in the project's layman report).