Danube Free Sky

Bird populations are influenced by naturally limiting factors (e.g. food, predation, weather, etc.), but are increasingly also affected directly and negatively by humans. Anthropogenic impacts range from the destruction or conversion of entire stretches of habitat, over the manifold negative effects of intensified agriculture and forestry and the increased disturbances caused by expanding leisure activities, to “technical pollution", for example through wind turbines or power lines, and this list is by no means exhaustive.

Protecting birds from powerline

Power lines are an integral part of the functioning of modern societies. However, they also pose multiple hazards to the bird world, with electrocution and collision being the best known.

Also, it should not be forgotten that power lines lead to a fragmentation of landscapes and alter the structure in open countryside, thereby potentially disrupting competitive conditions and, thus, changing the composition of the avifauna.

Basically, it can be assumed that the main causes of mortality in birds along power lines are electrocution in the case of medium-voltage lines, and collision in the case of high-voltage lines. This is due to the fact that insulator distances are too great in high-voltage power lines to be overcome by birds. An often fatal electrical discharge occurs either as a result of a conductor-earth-contact or a conductor-conductor-contact. The distinction between medium-voltage and high-voltage lines is not uniform; medium-voltage lines range from 1 kV up to and including 52 kV. All lines above this range are considered high-voltage and extra-high-voltage lines.


Electrocution from medium-voltage powerlines has often been proven to be a major cause of human-induced death in birds. Electrocution casualties included species of high conservation concern such as Saker Falcon (Falco cherrug), Red-footed Falcon (Falco vespertinus), European Roller (Coracias garrulus) and Eastern lmperial Eagle (Aquila heliaca). It is shown that most frequently affected species are those with slow reproduction rates such as birds of prey, falcons, owls, storks and also some songbirds. These birds are especially vulnerable in the open countryside, where trees are scarce and poles are often the only perches providing commanding views.


The collision of birds on power lines is particulary dangerous, because rivers naturally gather large numbers of water-associated birds, and on the other hand, many of these are particularly poorly able to avoid obstacles. It is shown that species with a high wing loading and low aspect ratio run a high risk of colliding with power lines. These species are characterised by fast flight, whereas the combination of a heavy body and small wings restricts swift reactions to unexpected obstacles. Also, it is shown that water-associated bird groups like divers, grebes, swans, ducks, cormorants and rails (all of which occur in high numbers along the Danube) have an increased collision susceptibility.

Platform for cooperation

DANUBE FREE SKY builds a platform for cooperation between nature conservation and the energy sector, raises awareness, defines standards and demonstrates feasibility by implementing pilot actions in most Danube countries. It intends to formulate technical solutions against collision for all wires crossing the Danube, including a road map for its implementation. Standards for marking of power lines will be defined, with a focus on finding innovative marking methods such as marking the electricity wires by drone.


You can find more information about topic in DANUBEPARKS's position paper: Electric Power Lines and Bird Conservation along the Danube river.