A comprehensive 15-year study published in the open-access Biodiversity Data Journal details the growing threat of extreme weather on White Storks (Ciconia ciconia) in Bulgaria. The research, which is part of the topical collection "Restoration of species of conservation importance," analyzes the admissions and treatment outcomes of injured storks at the Wildlife Rescue and Breeding Centre (WRBC) of the Green Balkans NGO between 2010 and 2025.
Led by Rusko Petrov alongside Eva Pastir of Trakia University and Gradimir Gradev of the Agricultural University of Plovdiv, the study examines how extreme weather events, specifically sudden spring frosts and wildfires, affect White Stork survival. Of 3,690 storks admitted to the WRBC over the 15-year period, researchers focused on 158 cases attributable to storms, hailstorms, strong winds, snowfalls with low temperatures, and wildfires.
A Tale of Two Disasters
The results revealed a stark contrast in survival depending on the type of weather event. Overall, 49% of the extreme weather victims (77 birds) were successfully rehabilitated and released back into the wild, while 51% (81 birds) of the cases were fatal. Only two birds remained permanently disabled and were transferred to other facilities.
Notably, juvenile storks are exceptionally vulnerable to extreme conditions because they are unable to flee the nest. This is particularly tragic during wildfires, which destroy nests and trap the flightless young while adult birds flee. Consequently, survival rates for fire-related incidents were strikingly low at just 33% (32 out of 97 cases). In contrast, storks affected by storms, hailstorms, and sudden snowfalls had a significantly higher rehabilitation success rate of 74% (45 out of 61 cases).
The Climate Change Connection
The researchers identified distinct geographic and climatic patterns linked to these rescues. Wildfires primarily clustered in the warmer Upper Thracian Plain, driven by prolonged summer heatwaves and human factors. Meanwhile, cold-related rescues were prevalent in the Danubian Plain, where cold continental air masses invade during winter and early spring.
These geographic patterns are consistent with global warming trends.
Warmer winters are prompting storks to migrate earlier, exposing the returning adults to sudden, deadly spring frosts and blizzards.
- explain the researchers
Simultaneously, the increasing frequency of summer heatwaves is fueling the nest-destroying wildfires that threaten the juveniles. Petrov also notes broader implications for other species:
Our research is focused on White Storks, but the impact is similar to many other bird species and most sensitive to it are the migratory and endangered ones. - he explains
To safeguard the White Stork, the authors underscore the urgent need for enhanced nest protection, improved wildlife rescue efforts, and proactive climate adaptation strategies to conserve the species.
Original source:
Petrov R, Pastir E, Gradev G (2026) Impact of extreme weather on White Stork (Ciconia ciconia) rehabilitation: admissions and outcomes (2010-2025). Biodiversity Data Journal 14: e182547. https://doi.org/10.3897/BDJ.14.e182547
****