Avian Nest-Site Selection Under Electromagnetic Stress: Evidence from Semi-Urban Ecosystems

Urbanizing landscapes increasingly expose wildlife to electromagnetic fields (EMFs) generated by telecommunication infrastructure, yet their ecological implications remain poorly understood. We investigated whether EMF exposure influences avian nest-site selection in three semi-urban ecosystems differing in land-use composition. Habitat utilization was first assessed relative to availability, followed by Bayesian logistic regression to evaluate the combined effects of landscape structure and EMF intensity across four frequency bands (900, 1800, 2100, and 2400 MHz). Birds did not select nesting habitats in proportion to their availability, indicating that habitat abundance alone does not determine nest placement. Instead, nest-site selection was associated with specific EMF variables and landscape features, with the influential EMF bands varying among sites. Negative relationships with nest occurrence were observed for EMF_900 and EMF_2400 in one landscape, and for EMF_1800 in another, while in the third area EMF_900 showed a negative association and EMF_1800 a positive one. These patterns likely reflect differences in local exposure thresholds and species-specific sensitivities within the breeding community. Our findings provide empirical evidence that existing EMF levels can shape avian nesting patterns in human-modified environments. Recognizing EMF exposure as an ecological factor is essential for urban planning and for managing biodiversity conservation in increasingly networked landscapes.