Background The globally threatened greater spotted eagle (Aquila clanga) is one of the rarest and least known bird species. Listed in Annex I of the Birds Directive, its numbers are declining with just 3000 breeding pairs worldwide. Greater Spotted eagle is found in Asia and Eastern Europe, which has a population of 800 pairs that may be mixed with the closely related lesser spotted eagle (Aquila pomarina). In the past this eagle species was commonly found on fen mires and wet meadow neighbouring wet forests. These habitats have disappeared, however, from most of the species’ former range in Europe due to drainage and disturbed water regime, conversion of meadows into arable land and the abandonment of traditional low intensity agriculture. Moreover, the cessation of vegetation cutting, grazing and burning has led to an overgrowth of eagle hunting sites by high reeds, willow bushes and succession forests of birch and alder. As the consequence, this eagle has disappeared from much of its EU territory. Though Poland is still home to around 35% of the EU population, it is found in just one breeding area in the northeast of the country, namely the Biebrza Valley. Objectives The overall objective of this project was to stabilise the population of greater spotted eagle in its last remaining breeding area in Poland by improving and increasing eagle hunting and nesting habitats. The aim was also to prepare scientific and administrative background/support for the effective continuation of the conservation work outlined in the national action plan. A partnership of two experienced NGOs and the Biebrza National Park (BNP) would help to effectively manage, monitor and implement the project activities in the project site (SPA Biebrza Valley/ Biebrza National Park with Buffer Zone) to achieve the following specific objectives: Improvement and enlargement of Aquila clanga hunting habitats; Protection of eagle nesting sites – mature, wet forests; Raised awareness of authorities, key stakeholders and the local public of the conservation needs of the species; and Identification of replicable mechanisms for ensuring long-term sustainable management for Aquila clanga in Poland. Results The AQC Plan project's main achievement was the drawing up a national action plan for greater spotted eagle (available from the project website: www.orlikgrubodzioby.org.pl ) for the next 20 years and the stabilising of its population in Poland. It achieved this outcome by carrying out extensive conservation actions, such as mowing and shrub removal on an area of more 650 ha in the Ostoja Biebrzańska Natura 2000 site. Such actions created open hunting sites and higher water levels in the breeding forests and hunting meadows. Specifically, the hydrological conditions of habitats in the vicinity of the Polkowo Ditch were re-established (Ostoja Biebrzańska Natura 2000 site). Breeding rates of the species were also boosted through the creation of artificial nests and by purchasing forested areas. The project also closed some tourist paths till the end of the breeding seasons. These actions are also benefiting other species, such as the acquatic warbler (Acrocephalus paludicola) the great snipe (Gallinago media) and the Eurasian curlew (Numenius arquata). The research carried out by the project team furthermore yielded valuable scientific data that created a base for new conservation recommendations for Management Plan of the Natura 2000 site (PZO). Replicable mechanisms for ensuring the long-term sustainable management of sites for greater spotted eagle in Poland were identified but not yet finally agreed (some documents are still not legally operational). A key action was thus to raise the awareness of authorities, key stakeholders and the local public of the conservation needs of the species and its specific habitat requirements. Hunting during the migration period can be particularly detrimental to the species, an issue that was raised following the end of the project. The beneficiaries are fostering international cooperation to limit hunting along key migration routes.