Wind energy in forests: reaction of bird and bat populations in the context of the energy transition

Abstract

This article assesses the rationale and consequences of siting wind turbines in forests in the context of the energy transition. The starting point is the observation that in many countries with significant forest cover, planning pressure from the wind energy sector on forested areas is increasing. Based on an extended review of both peer-reviewed and “grey” literature (including a multilingual search), we synthesize known mechanisms of impact on birds and bats: (1) collisions; (2) fragmentation and habitat loss resulting from “forest urbanism” (roads, assembly areas); (3) acoustic and visual effects that may alter territorial and communication behaviors. We document substantial spatial and seasonal variability of risk:

for both bats and birds, mortality peaks during migration periods, in late summer and autumn, and mortality rates tend to be high on forested mountain ridges. We also highlight evidential limitations: including the rarity of BACI designs, the lack of data linking animal activity with actual mortality, and the representativeness issues of site selection. We discuss mitigation within a hierarchy of avoid → minimize → compensate, including spatial planning that excludes core refugia and migration corridors, real-time detection with conditional shutdowns, and reduced infrastructure footprints. We conclude that although tools to reduce mortality are being rapidly improved, rational decision-making requires adaptive monitoring and clearly defined action thresholds. A fundamental premise remains: every form of energy production entails environmental costs – policy and practice should aim to reduce and transparently account for them.