Birds and powerlines in Italy: an assessment

Abstract

Powerlines may pose severe threats to bird populations. We assessed the significance of powerlines as a source of avian mortality within the Italian electric transmission and distribution system. We reviewed data from 11 mortality censuses and compiled a list of species that were found among powerline victims in Italy, based on over 1,300 reported individual casualties. Overall, 95 species of birds were reported among powerline victims (19% of Italy's total species). The number of recorded species was compared with the number of species in the Italian list, after grouping species based on morphology and ecology. Some groups (e.g. raptors, herons, storks and allies) were highly affected, while others (e.g. passerines and allies) appeared to be poorly represented among species involved in powerline accidents. Furthermore, we evaluated the validity of a published discriminant model for the classification of bird species as collision or electrocution victims according to body measurements. The application of the available model classified 54.7–73.5% of Italian species correctly (depending on the species included), compared with 88.6% of the original dataset. Two new discriminant models based on Italian powerline casualties classified 80.9–81.1% of species correctly. This approach can be a useful tool in assessing collision and electrocution risk for species in different geographical areas. While we recognize the need for a general preventive approach for reducing the bird–powerline conflict, our review highlights once more the importance of local situations, where powerlines may have a strong impact on avian communities.