Factors influencing wind turbine avoidance behaviour of a migrating soaring bird

Abstract

Wind energy production has expanded as an alternative to carbon emitting fossil fuels, but is causing impacts on wildlife that need to be addressed. Soaring birds show concerning rates of collision with turbine rotor blades and losses of critical habitat. However, how these birds interact with wind turbines is poorly understood. We analyzed high-frequency GPS tracking data of 126 black kites (Milvus migrans) moving near wind turbines to identify behavioural mechanisms of turbine avoidance and their interaction with environmental variables. Birds flying within 1000 m from turbines and below the height of rotor blades were less likely to be oriented towards turbines than expected by chance, this pattern being more striking at distances less than 750 m. Within the range of 750 m, birds showed stronger avoidance when pushed by the wind in the direction of the turbines. Birds flying above the turbines did not change flight directions with turbine proximity. Sex and age of birds, uplift conditions and turbine height, showed no effect on flight directions although these factors have been pointed as important drivers of turbine collision by soaring birds. Our findings suggest that migrating black kites recognize the presence of wind turbines and behave in a way to avoid then. This may explain why this species presents lower collision rates with wind turbines than other soaring birds. Future studies should clarify if turbine avoidance behaviour is common to other soaring birds, particularly those that are facing high fatality rates due to collision.

Global Review on Environmental Impacts of Onshore Wind Energy and Their Implications for Forest Ecosystems

“…Birds might recognize and become habituated to the presence of WTs and behave to avoid them [32,47,61,80,122,138,153,158,159]. Macro-avoidance describes the avoidance of an entire wind farm by adjusting flight paths to avoid entering the area occupied by groups of WTs [80,94,107] and is a tradeoff between avoidance-induced habitat loss and reduced collision mortality [105,158].…”

“…It affects habitat use, territorial behavior, and breeding success of animals [125]. Consequences are, for instance, reduced bird densities [49,125], avoidance behavior of bats [58] and birds [122], alterations of wildlife migration routes [64], or other behavioral impacts [59,125,138]. Operation noise can be a deterrent [132] or an attractive effect [150].…”

Psycho-Acoustic Survey on Wind Turbine Noise and Its Environmental Impact

“…The black kites learn the turbine mechanism and try to avoid the obstacles. The birds did not change their direction but they recognize the turbine behavior and avoid it [35]. A majority of the people reported this and stated that the poor maintenance of the WTs was the reason behind this.…”

Nesting flight statistics for wind turbine planning: a MoveApps workflow

“…Many GPS tracks have been collected by a large number of scientists, wildlife managers and conservation groups worldwide and uploaded and archived in online databases like Movebank (Kays et al 2022). For some species, the data have been analysed in relation to collision risk (Schaub et al 2020; Pfeiffer and Meyburg 2022), wind turbine avoidance behaviour (Chamberlain et al 2006; Watson et al 2018; Santos et al 2022) and habitat loss (Marques et al 2020). However, much available tracking data has not been analysed for wind turbine collision risk applications.…”