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Providing evidence to improve practice

Individual study: Marking of transmission line groundwires reduces bird collisions in Extremadura, southwest Spain

Published source details

Alonso J.C., Alonso J.A. & Muñoz-Pulido R. (1994) Mitigation of bird collisions with transmission lines through groundwire marking. Biological Conservation, 67, 129-134


This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.

Mark power lines to reduce incidental bird mortality Bird Conservation

A controlled before-and-after trial in the winters of 1989-90 and 1990-1 in mixed woodland and farmland in Extremadura, Spain (Alonso et al. 1994), found there were fewer collisions and fewer birds flying between lines following the marking of four sections of line (60% reduction in fatalities: 45 vs. 18; 61% decrease in birds flying between lines: 357 birds/day vs. 124 birds/day). There were no such decreases at unmarked spans of wire (19 vs. 15 fatalities). Markers were coloured PVC spirals (1 m long, 30 cm in diameter) attached every 10m.