Power Lines and Birds: Drivers of Conflict-Prone Use of Pylons by Nesting White Storks (Ciconia ciconia)

Energy infrastructure is expanding at a global scale and can represent a major threat to wildlife populations. Power lines are one of the main sources of human-induced avian mortality due to electrocution or collision, but many species use electricity pylons as a structure for nesting. Pylon nesting results in human-wildlife conflict because it can cause power outages and structural damage to power lines. The white stork (Ciconia ciconia) is a large-size semicolonial species that increasingly nests on pylons, causing growing operational and economic issues to power companies and energy consumers. In this study, the likelihood of problematic pylon use by nesting storks was predicted using a suite of explanatory variables related to the availability of foraging habitat and human disturbance. During a five-year period (2015-2019), we assessed the distribution of stork nests removed from the highly-risky top part of transmission pylons (220-400 kV) by power company technicians in South western Spain. A total of 839 nests were removed from 11% of the transmission pylons (n = 1196) during the study period. Pylon use intensified on pylons located near to landfills, surrounded by high proportion of grassland, and when close to freshwater sources (water body or river) and other occupied pylons. Human disturbance was unlikely to deter storks from using pylons and pylon use increased in urban areas. The approach used here to predict pylon use by nesting birds has applications for both human-wildlife conflict mitigation and conservation purposes where endangered species use human infrastructure. Power companies may use this kind of information to install anti-nesting devices (to reduce power outages and avian mortality or nesting platforms on suitable pylons (to promote pylons use by endangered species), and to account for the likelihood of conflict-prone use of pylons when siting future power lines.

Automated summary

Energy infrastructure expansion poses a major threat to wildlife, particularly due to the adverse effects of power lines on avian mortality. This study focuses on the increasing nesting of white storks on electricity pylons and its resulting conflicts with power companies and consumers. Factors such as proximity to landfills, availability of grassland, freshwater sources, and occupied pylons contribute to the intensified use of pylons for nesting. The study also highlights the limited impact of human disturbance and the higher pylon use in urban areas.