Visual markers applied to power lines can help to attract flying birds’ attention earlier and avoid collision. Thus, grid operators apply ‘wire markers’ (or bird flight diverters) to lines in high-risk areas. However, with many products on the market and a multitude of factors influencing how effective markers are in reducing collisions, it can be difficult for grid operators to get an overview of what the science says regarding best practice in wire marking.
Against this background, RGI undertook a research and communication initiative and created a global overview of available research. This work has been guided by the advice and support of several experts from academia, grid operation and civil society. The purpose of this initiative is to provide a visual summary of available research on wire marker effectiveness and the factors influencing collision risk, to help inform the decision basis for collision-risk mitigation measures.
This initiative was launched in the context of the collaborative conference ‘Wingspan: Partnerships for a bird-friendly energy transition’. In case of questions, please contact us below.

Download the materials
01
Brochure
The brochure gives an abridged, user-friendly overview on the topic and available research. As size of this brochure limited the level of detail of the information it could contain, we established standards for the research studies included to ensure scientific vigour, which limited the number of wire markers featured in the brochure.
02
Methodology Report
The Methodology Report provides a more comprehensive overview of:
- Current state of research on birds’ susceptibility to collision;
- Factors influencing risk;
- Research-based ‘basic principles’ for effective wire markers;
- Important considerations for grid operators;
- Some wire markers available on the market.
03
Study Summary Table
The Study Summary Table contains a review of 50 studies into the effectiveness of wire markers.
04
Annex I
A summary of relevant studies and guidelines from the German context on wire marker effectiveness and evaluation of bird susceptibility to power line collision, which were previously not available in English.
05
Annex II
This table shows ‘reference species’ which can be used to evaluate the susceptibility of ‘comparison species’ for which no research on collision risk susceptibility is available. See Annex I for an explanation of methodology.
contact
Liam Innis
liam[at]renewables-grid.euSenior Manager – Energy Ecosystems

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