Rescuing the aquatic warbler – the greatest species conservation success in years

The aquatic warbler is one of Europe’s most endangered songbirds. Thanks to programs run by the Polish Society for the Protection of Birds (OTOP), the population of this species in Poland is starting to recover. The latest data from the West Pomeranian Voivodeship show that individuals translocated from the Biebrza Valley are returning to the release site and breeding successfully. This marks a breakthrough in the fight to save this valuable species.

The aquatic warbler – a bird that could not be lost

The aquatic warbler (Acrocephalus paludicola) is a small bird inhabiting peatlands and marshes, dependent on constantly wet habitats. In the 20th century, it was still common across Europe, but today its range is limited mainly to a few sites in Poland, Belarus, and Ukraine. Classified as globally endangered, the species relies heavily on Poland for its survival. Climate change and the drainage of wetlands have caused the aquatic warbler to lose most of its natural breeding grounds.

Translocation from Biebrza

The core element of the OTOP project is chick translocation – moving young aquatic warblers from the Biebrza Marshes in the Podlaskie Voivodeship to the Natura 2000 area “Rozwarowo Marshes” in Western Pomerania. This site was not chosen by accident – just over a decade ago, about 40% of the local population used to breed there.

After intensive preparations and fieldwork, a total of 103 chicks were taken, along with their nests, from breeding sites in the Biebrza area, then transported and released in Western Pomerania. Monitoring in 2023 and 2024 confirmed that the method works. Seventeen individuals were recorded returning to the area: twelve adults and five juveniles. For the first time in many years, the presence of females and successful breeding was confirmed, proving that the population is beginning to recover.

The result of years of work and cooperation

Rebuilding the aquatic warbler population would not have been possible without many years of preparation. In cooperation with LIFE project partners, OTOP created new, safe habitats – restoring water regimes, mowing reedbeds, and controlling water levels to maintain optimal breeding conditions. This work requires precision and patience, as even a small hydrological change can undo several seasons of effort.

The activities in Western Pomerania continue the earlier successes from the Biebrza Valley, where habitat protection and breeding programs have been implemented. Every returning bird is a result of long-term strategy, and this year’s data show that the effort is bringing measurable results.

Drought halted but did not derail the project

An exceptionally dry season in 2024 halted another planned translocation, but conservationists emphasize that this is only a pause, not the end of the program. OTOP plans to resume activities once hydrological conditions allow. In the meantime, work continues on expanding the network of breeding areas and monitoring birds returning from their wintering grounds. Observations from this year confirm that previously released individuals not only return but also breed successfully, making this one of the project’s greatest achievements since 2019.

The aquatic warbler returns to the map of Europe

Polish efforts are part of the international LIFE4AquaticWarbler project, which also involves Lithuania, Germany, Hungary, and Ukraine. According to OTOP, fewer than 11,000 singing males remain worldwide, nesting in no more than 50 sites. This demonstrates how crucial every successful breeding attempt and every restored habitat is.

The new nine-year LIFE program aims to restore over 3,900 hectares of wetlands and translocate 760 chicks to at least six populations across four countries. The goal is to increase the number of breeding sites and reduce the risk of local extinction. In this context, the success at the Rozwarowo Marshes takes on international importance – it is proof that long-term conservation delivers tangible results and offers hope for the recovery of the species across the Baltic region.