2012

Because of their size and prominence, above-ground electrical infrastructures represent significant risks for birds if certain precautionary measures are not taken. Most above ground power lines (both medium voltage distribution lines and medium to high voltage transmission lines) present potentially fatal risks for birds through risks of collision with overhead wires and the risk of electrocution. A bird collision occurs when a flying bird physically collides with an overhead cable. The bird is typically killed by the impact with the cable, the subsequent impact with the ground, or dies from the resulting injuries. Electrocution of a bird occurs when it bridges the gap between two energised components or an energised and an earthed (also called ‘grounded’) component of the pole structure. This results in a short circuit, with electric current flowing through the bird’s body, and electrocution, often accompanied by an outage of the electricity supply.

Power lines are one of the major causes of unnatural deaths for birds in a large part of the African-Eurasian Flyways with, for example, many millions of birds fall victim to collisions each year in Germany alone (Hoerschelman et al., 1988). In several European countries a relatively high proportion of collision victims involve endangered species of Appendix I of the Birds Directive, e.g. European Spoonbill (Platalea leucorodia) and Black-tailed Godwit (Limosa limosa) in the Netherlands, and bustards and eagle species in Spain, Portugal and Hungary. The problem is also believed to be serious in Africa. In South Africa, for example, the survival of several critically endangered species, such as Blue Crane (Anthropoides paradisea) and Ludwig’s Bustard (Neotis ludwigii), is believed to be severely threatened due to collisions with power lines. Unfortunately, for most of the continent, concrete data are missing.

Although nowadays electrocution is not much of a problem in Northwest Europe, where most of the lower voltage lines have been placed underground, there are still many countries, both in Europe and elsewhere along the African-Eurasian Flyways, where low and medium voltage lines have not been equipped with proper mitigating measures. In these countries electrocution poses a serious threat to a number of populations, in particular storks and raptors that build their nests on the electricity poles or use the poles as perches. There are indications that for certain bird species, particularly larger species, electrocution may be the most serious cause of death; even more than road traffic (Haas et al., 2005).

Electrocution of birds is not just a conservation issue; it also has serious economic and financial consequences due to the disruption to power supplies and thereby presents a cause for concern among electricity distribution companies. Unfortunately, many electricity companies are not aware of, or are reluctant to apply, state-of-the-art bird safety provisions. Sensible changes to the routing of the power lines and changes to the structures (both marking overhead wires and modifications to avoid electrocution) can effectively reduce the risk posed to birds by 50 % or more. A large number of studies, including previous reviews, have been published on these issues.

However, the information is scattered, not always easily accessible (e.g. in internal reports and ‘grey literature’), much is of anecdotal character and an overview of the magnitude of the conflict between birds and electricity power grids at the scale of the African-Eurasian region is lacking. The same applies for the solutions to avoid electrocution and various measures to mitigate collisions. Therefore, the UNEP/AEWA Secretariat, also on behalf of the Secretariats of the Convention on Migratory Species (CMS) and the CMS Raptors MoU, commissioned a review of all aspects of the conflict between migratory birds and electricity power grids, and guidelines for mitigating and avoiding this conflict within the African-Eurasian region. Because of the extensive information collated, the review of the conflict between migratory birds and the electricity power grids in the African-Eurasian region has been published in a separate document, as CMS Technical Series No. 30 and AEWA Technical Series No. 42, titled ‘Review of the Conflict between Migratory Birds and Electricity Power Grids in the African-Eurasian Region’ (Prinsen et al., 2011a).

The international report provides important background information to this guidelines document. Guidelines on the conflict between birds and power lines have been published before, most notably the Convention on the Conservation of European Wildlife and Natural Habitats (the Bern Convention) published detailed guidelines to be implemented for the protection of birds on medium voltage power lines, based on Haas et al. (2005), and the Bern Convention Standing Committee in 2004 adopted Recommendation No. 1102 on minimising adverse effects of above ground power lines. Furthermore, in 2002 CMS/COP 7 adopted a resolution (No. 7.4 "Electrocution of Migratory Birds”3), which called on Parties and non-Party Range States to implement technical and legislative measures to mitigate the electrocution of birds on power lines, based on guidelines published in a brochure by NABU (German BirdLife partner), which is a precursor of Haas et al. (2005). Also for North America, extensive practical guidelines are available, published by APLIC (1994, 2006).
These guidelines and the accompanying International Review (Prinsen et al., 2011a; UNEP/CMS/Inf.10.38) present the available information (including references to other reviews) on the topic from the wider area of the African-Eurasian region. These documents summarise the latest technical standards on electrocution
mitigation and review and present guidelines to mitigate collision risk for birds, a topic that received less attention in both the guidelines of the Bern Convention and the 2002 CMS Resolution 7.4.

This guideline document presents appropriate actions, both legislative as well as technical, summarises the state-of-the-art mitigation/avoiding measures and gives suggestions for evaluation and monitoring. Providing detailed technical instructions on the construction of mitigation measures is outside the scope of
these guidelines; for these we refer to existing technical literature and recommend APLIC (1994, 2006), Haas et al. (2005) and Haas et al. (2008) for more technical details on, for example, construction techniques.