Background The population of the common tern (Sterna hirundo) in Slovakia in 2008 was estimated to be 925 pairs, which is similar in size to the population in Hungary (950 pairs) and higher than that in Austria (250 pairs) and the Czech Republic (500 pairs). Given the size of the country, the Slovakian population of common tern is one of the densest in Europe, excluding Ukraine. However the common tern is limited is present only in a few sites. The most important nesting site is the SPA Dunajské luhy, where 306 pairs nested in 2010 and 377 pairs in 2011, and the SPA Dubnické štrkovisko with 280 pairs. The number of the nesting pairs in each of remaining sites was fewer than 100. The total number of the nesting terns in the five project sites represents 80% of the national population. Nesting at the SPA Dunajské luhy, however, is affected by disturbance, especially that caused by visitors. The maintenance of such a strong population of the common tern is therefore unsustainable without implementation of conservation measures. Unfavourable weather conditions, in particular floods, has lowered the success rate of nesting in the SPA Dubnické štrkovisko, while unfavourable management of sites and the inappropriate structure of biotopes decreased nesting in other project sites. The common tern breeding habitats are important for securing national populations of other bird species listed in Annex I of the Birds Directive, such as the Mediterranean gull and redshank. Objectives The 'STERNASK' project aimed to conserve the populations of the common tern, an Annex I-listed bird species, in five SPAs in the western and northern part of Slovakia, reversing population decreases. It aimed to increase the population by 15% on 2010 figures and increase breeding success by 20%. The improvement of the conservation status would be achieved by enlarging the area of the common tern habitats and breeding sites in those areas not threatened by random external factors or unsuitable management. Expected results: A conservation programme for the common tern in Slovakia; Management plans for two SPAs (SKCHVU006 & SKCHVU026); Restoration of 12 ha of habitats for the benefit of the terns; Construction of new nesting islands (three islands covering 400m2); Removal of invasive species at the project sites; Reduction in disturbance by visitors at the project sites; and Improvement of the water regime management at critical sites.Results The project failed to start the standard implementation of the foreseen activities because of missing funding. The project did not achieve the foreseen objectives, but several minor results for the sake of the Common Tern by voluntary work, namely: monitoring of the species, removal of invasive species in limited extent and regulation of public access to the bird territories by promoting correction of a wrong public notice.