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Providing evidence to improve practice

Individual study: Marking 12 kV conductors reduces avian collision mortality in wetland/arable complex

Published source details

Yee M.L. (2008) Testing the Effectiveness of an Avian Flight Diverter for Reducing Avian Collisions with Distribution Power Lines in the Sacramento Valley, California: PIER Final Project Report. California Energy Commission report.


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 replicated, controlled before-and-after trial over the winters of 2003-4, 2004-5 and 2005-6, in mixed wetland and crops on Staten Island, California, USA (Yee 2008), found a 60% reduction in collision mortality across all species following the installation of ‘Firefly bird flappers’ on 20 spans of a 5.6 km section of 12 kV wire. There was also a smaller (approximately 10%) reduction in mortality in nine spans adjacent to marked spans. There was no corresponding decrease in collision mortality in 20 unmarked spans. However, markers did not appear to have an effect on bird flight behaviour. Markers were 15 x 9 cm acrylic sheets of two contrasting colours with a luminescent strip and placed at 15 m intervals, staggered to appear 5m apart. A total of 65 fatalities were recorded over the three winters.