Background The Aquatic warbler (Acrocephalus paludicola) is the rarest migratory songbird in Europe, and the only globally threatened passerine bird found in mainland Europe. It is listed as “vulnerable” in the IUCN Red List of globally threatened species. In Lithuania and Latvia, aquatic warblers are found in habitats that depend on human management (i.e. mowing and burning of vegetation). If suitable habitats are abandoned by human land users, they become overgrown with vegetation and unsuitable for breeding and the birds disappear within a short time. In eutrophic habitats even the timing of land use can be crucial: if mowing is too late, breeding habitats may deteriorate; if mowing is too early it will destroy the broods of aquatic warblers along with other endangered breeding birds. Conservation of these birds requires adjusting mowing to the occurrence of aquatic warblers which may not always meet the interests of land users. Adjustment of land use is currently difficult to achieve because of the lack of incentive for farmers. Moreover, areas that have already been derelict for many years (10 or more in some project sites), special restoration activities (extermination of bushes, reed stands or a full-year grass layer) should be implemented in order to restore meadows for further common or specific management. Objectives The main project objective is to ensure the favourable conservation status of the aquatic warbler (Acrocephalus paludicola), which breeds in wet meadows and open fens dominated by sedge grasses. The project will also bring added value to the conservation of other rare species that breed in similar habitats, namely the great snipe (Galinago media) and corncrake (Crex crex). Conservation of the species will be achieved by: restoring important habitats; applying measures to ensure economic and social motivation to maintain management of important habitats in the long-term; applying demonstration measures to increase the area of suitable habitat; and raising awareness about conservation needs and initiatives as well as species ecology to increase public acceptance of the project. The proposed project does not limit itself to focusing on single conservation measures, but addresses conservation of targeted species in a holistic way. The project’s approach includes: establishing preconditions for a reasonable financial income for the landowners to continue conservational management; focusing on social aspects to motivate farmers to be involved in targeted species conservation; capacity building of nature conservation authorities; strengthening scientific experience of the application of new management methods (e.g. reed burning); influencing the legal framework to establish suitable conditions for agri-environmental management in the project sites; and learning from other countries and replicating best practices in the surrounding areas that could be a valuable habitat for the target species. Expected results: Ex ante monitoring of the breeding aquatic warbler and its habitats on all six project sites. Precise maps for each site will show the location of all singing males and provisioning females as well as delineating the important habitats; An agri-environmental scheme for the Nemunas delta targeting specific conservation measures needed to achieve the favourable conservation status of the aquatic warbler. The scheme will be integrated into the national rural development programme; The creation of some 300-350 ha of ecological priority land-use plot in the project site LT02, where further agri-environmental management measures can be implemented; The publication of guidelines for economically sustainable aquatic warbler habitat management (2 000 copies in Lithuanian, 1 000 copies in Latvian and a PDF in English); A communication strategy for landowners and ArcGIS training courses; Raised capacities of the administration of the protected areas through a communication strategy for landowners and ArcGIS trainings; and Three study visits (possibly to Poland, Belarus and Germany) to enable some 40 experts, environmental officials and landowners of project areas to gather relevant experience and know-how.