Defining Collision Risk: Lesser Flamingo Phoeniconaias minor Power Line Collision Sensitivity and Exposure for Proactive Mitigation

Abstract

Lesser Flamingos Phoeniconaias minor regularly collide with power lines in South Africa. Attaching light-emitting markers to overhead wires seems to be an effective mitigation measure; however, the cost of these devices is prohibitive of large-scale installation. Spatial predictions about flamingo collision risk are thus important for achieving efficient and effective proactive mitigation. In this study, collision risk was defined as a combination of factors related to threat exposure. A habitat suitability index was developed according to changes in surface water occurrence and Chlorophyll-a concentrations, which proved accurate in predicting Lesser Flamingo occurrence. Habitat suitability, and three other species and threat exposure variables, were then used in logistic regression models predicting the occurrence of historic collisions. The most parsimonious model included habitat suitability and flight height. Flamingos were only at risk of collision with power lines when flying lower than 50 m and within 3 km from the water’s edge. High-risk power line sections were thus identified from 3 km buffers around waterbodies ranked according to habitat suitability, which significantly reduced the number of power line spans predicted for proactive marking. While our models indicated that aspects related to exposure were important for predicting flamingo power line collisions, aspects related to sensitivity (e.g., nocturnal behavior) must also guide the choice of mitigation.