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