• Energy Research

Human-induced direct mortality affects huge numbers of birds each year, threatening hundreds of species worldwide. Tracking technologies can be an important tool to investigate temporal and spatial patterns of bird mortality as well as their drivers. We compiled 1704 mortality records from tracking studies across the African-Eurasian flyway for 45 species, including raptors, storks, and cranes, covering the period from 2003 to 2021. Our results show a higher frequency of human-induced causes of mortality than natural causes across taxonomic groups, geographical areas, and age classes. Moreover, we found that the frequency of human-induced mortality remained stable over the study period. From the human-induced mortality events with a known cause (n = 637), three main causes were identified: electrocution (40.5 %), illegal killing (21.7 %), and poisoning (16.3 %). Additionally, combined energy infrastructure-related mortality (i.e., electrocution, power line collision, and wind-farm collision) represented 49 % of all human-induced mortality events. Using a random forest model, the main predictors of human-induced mortality were found to be taxonomic group, geographic location (latitude and longitude), and human footprint index value at the location of mortality. Despite conservation efforts, human drivers of bird mortality in the African-Eurasian flyway do not appear to have declined over the last 15 years for the studied group of species. Results suggest that stronger conservation actions to address these threats across the flyway can reduce their impacts on species. In particular, projected future development of energy infrastructure is a representative example where application of planning, operation, and mitigation measures can enhance bird conservation. This work was funded by the MAVA Foundation trough the MAVA Safe Flyways Energy project, specifically the M7 Birds – Reducing mortality of migratory birds and vultures in the Mediterranean 2016–2022.

Pylons of utility lines are commonly used by breeding birds as structures for supporting their nests. Nesting near power lines, however, exposes adult birds and their offspring to the electric and magnetic fields (EMFs) produced by the current. Therefore, we searched for possible relationships between the magnetic field (MF) magnitude experienced by wild kestrel (Falco tinnunculus) nestlings grown on pylons and different health-related variables: body condition, serum concentration of carotenoids, reactive oxygen metabolites (ROMs; marker of early oxidative damage), serum anti-oxidant capacity (OXY), and the ratio between ROMs and OXY (index of oxidative stress). No significant relationships were found between the MF magnitude or squared MFs and any of the variables considered. Comparisons with values recorded in nestlings from non-exposed nests seem to confirm the absence of any effect of exposure to MFs produced by power lines on the variables considered.