Efficacy of different types of “bird flight diverter” in reducing bird mortality due to collision with transmission power lines

Miguel Ferrer,Virginia Morandini,Ryan Baumbusch,Roberto Muriel,Manuela De Lucas,Cecilia Calabuig

doi:10.1016/j.gecco.2020.e01130

Miguel Ferrer, Virginia Morandini + Show 4 more

Open Access

https://doi.org/10.1016/j.gecco.2020.e01130

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Abstract

Bird diverter devices were developed to improve power line visibility for birds and reduce their risk of collision. However, differences in efficacy between types of devices, and in some cases conflicting results, place in question the ability of these devices to reduce collision risk to birds. Here, we investigated the efficacy of three types of flight diverters in reducing avian collision with power lines: yellow spiral, orange spiral, and flapper, additionally we used unmarked spans as a control. We recorded bird collisions and estimated removal rates of bird casualties by scavengers in three different 400 kV transmission lines comprising 133 spans in southern Spain. A total of 131 dead birds from 32 species were found. The power line and the type of marker significantly affected avian mortality. The flapper flight diverter was responsible for a 70.2% lower mean avian mortality rate (95% Confidence Interval: 50–90%), followed by the orange spiral (mean = 43.7%, CI = 15.8–71.6%) and the yellow spiral (mean = 40.4%, CI = 2.8–78%), compared to control spans. Flappers were the only marker that showed greatest reduction in relation to non-marked spans. The flapper flight diverter showed the highest reduction in mortality and the narrowest confidence interval when tested in different environmental conditions, and thus may serve as a better alternative to the more commonly used spiral flight diverters.

Highlights

During the last 35 years, bird mortality caused by overhead electrical transmission and distribution lines has been an increasing concern for both conservationists and environmental management authorities
There are two main problems associated with birds and power lines (Ferrer, 2012): electrocution on distribution power lines and collision with the wires
The purpose of the present study was to assess the efficacy of reducing avian collisions at three different transmission power lines, with three commonly used types of flight diverters: PVC yellow spiral, PVC orange spiral, and a recently developed “Bird flapper”, with the shape of a cross with orange and red sides, inserted with reflective stickers (Fig. 1)

Summary

Introduction

During the last 35 years, bird mortality caused by overhead electrical transmission and distribution lines has been an increasing concern for both conservationists and environmental management authorities. (Alonso et al, 1994; Savereno et al, 1996; Janss and Ferrer, 1998; Royen and Ledger, 1999; Anderson, 2002; De La Zerda and Rosselli, 2003; Lehman et al, 2007; Murphy et al, 2009; Jenkins et al, 2010; Shaw et al, 2010a, 2010b; Calvert et al, 2013; Dashnyam et al, 2016) These accidents have been documented for approximately 350 bird species (Manville, 1999; Ferrer, 2012) with some rough estimates of the magnitude of the problem: 1 million birds per year in the Netherlands (Koops, 1994), 175 million per year in the United States (Manville, 2009), around 1 billion per year worldwide (Hunting, 2002). The collisions with power lines are a problem for the power companies due to potential outages following collisions (Bevanger, 1999)

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