Background The project area encompasses the wetland areas of five Polish national parks: Biebrzański, Drawieński, Narwiański, Ujście Warty and Słowiński. All of these parks are located on Natura 2000 special protection areas (SPAs) and some areas are also protected by the Ramsar Convention on Wetlands or are nominated as new UNECSO biosphere reserves. Unfortunately, a decline in the number of birds inhabiting wet and marshy habitats has been recorded in all five areas. Therefore, there is a need to study, monitor and limit the known threats to the wetland bird populations. A decline of wetland habitats and threats from invasive predatory species are the key threats to the species in the five project locations. Objectives The Polskie Ostoje Ptaków project aimed to implement and improve protection measures for a number of important European wetland bird species that breed in SPAs within the five Polish national parks. This objective would be achieved by improving habitat conditions in order to increase the breeding success of the targeted wetland bird species and, at the same time, curbing pressures from invasive alien predatory species, particularly the American mink (Neovison vison) and the common raccoon (Procyon lotor). Results The project achieved most of its objectives. It purchased 278 ha of land ahead of the restoration of 400 ha of open habitats for birds breeding in such habitats. Degraded areas were recovered by mowing of grass and bush removal, allowing for restoration of open habitats for birds breeding in habitats with low vegetation. Predation pressure caused by American mink and common raccoon was lowered by removing 829 mink and 171 raccoon. Trapping methods were adapted to specific local conditions in the national parks. The distribution of the traps (every 500m along the water line) helped identify places of particularly intense penetration by predators and migration corridors. Genetic analysis of trapped animals was performed, clearly proving the impact of mink farms, their location and size on wild mink populations. Information on the locations of mink farms was collected throughout the country. Genetic analysis (microsatellite and single nucleotide polymorphism (SNP) markers) in conjunction with spatial analysis (GIS analysis) confirmed the relationship between farm size and proximity to national parks and the percentage of individuals with the farm genome in wild mink population. Eight trapped raccoons were also equipped with telemetry GPS/GSM collars. These collars allowed their movements to be tracked during the whole of the 2013 season. By analysing the collected data, researchers could determine whether there are other effective methods of reducing the very high rate of raccoon colonisation than intensive trapping and elimination. Only the hydrological conditions can be perceived as limiting factor. Varying levels of water and seasonally flooding can be a barrier to the movement of raccoons. Safe bird breeding sites were created by situating nesting boxes that were secured with spiked collars and steel rims. The large-surface nesting colonies were further protected with electric fences. These measures ensured safe sites for nesting and hatching that are effectively protected against predators. The aims of the project will be continued through ongoing reduction of invasive alien predators, and the continued use of electric fences at the wader breeding sites. Mowing and nesting box maintenance will also benefit breeding. Finally, the project held five seminars for small groups (40 people) of experts/researchers in the fields of nature conservation, nature management and protection of Natura 2000 areas, as well as hunters and local authority representatives. An international conference allowed for the exchange of experiences in the fight against invasive species and prevention of environmental degradation in other countries and regions. Brochures, books, leaflets, billboards and a website were also produced. Additionally, several specialised training sessions for staff of national parks and forest employees were provided on regular monitoring and mink trapping. Further information on the project can be found in the project's layman report and After-LIFE Conservation Plan (see "Read more" section).