costa, j fagundes, i.;gouveia,c. · wetlands, with high bird densities are most important for...
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Costa, J[1], Rochinha, CA[2]; Costa, L. [1]; Infante, S.[3]; Fagundes, I. [1]; Veríssimo, C. [1]
Inter-Institutional CooperationAn overall study of 3 years started in 2003
thanks to protocols between 2 NGO’s (SPEA
and Quercus), the Governamental
Conservation Institute (ICNB) and two
Electrical Companies: REN -. Very High
Tension Distribution (>110 kV) and EDP
Distribuição – Medium and High Tension
Distribution (1-110 kV)
As a result of this cooperation, there were
established internal norms for the study
and application of mitigation measures
both for REN (2005), EDP Distribuição
(2010), and public guidelines for the study
and mitigation of power lines impact (ICN,
2005).
Later, this cooperation has been shaped into
a Technical Commission for Birds and
Power Lines Surveillance (CTALEA), with
the presence of EDP Distribuição , ICNB,
SPEA and Quercus, which has a consultive
role for projects and works with Medium and
High Voltage
Projects in inland Portugal, Azores and Madeira islandsThe average calculated mortality in
continental Portugal is 3.27 birds/km/year
by collision and 0.17 birds/pylon/year
through electrocution. The total number of
deaths counted in the impact study being
above two thousand birds, for 1109 km of
Medium and High Tension electrical lines
and 7171 pylons prospection.
In Madeira Island, SPEA is evaluating the
collision impact for three sensitive and
globally threatened species, the Eurasian
Woodcock Scolopax rusticola, The Madeira
Storm-petrel Oceanodroma castro and the
Bulwer's Petrel, Bulweria bulwerii.
In the Azores, we are evaluating
electrocution impact, specially on the
Buzzard, Buteo buteo, being the maximum
observed mortality about 0,26 birds/pylon/yr,
in Santa Maria Island.
Main species affected
The most frequently species found is the
white stork, Ciconia ciconia mainly victim to
electrocution around nesting sites, but also
to collision.
While Passerines are mainly affected by
collision, birds of prey account for 40% of
total electrocutions: the Common Buzzard
(Buteo buteo), reaches the highest mortality
found for a single species. Other common
species found are the Common Kestrel,
Falco tinnunculus, the Short-toed Eagle,
Circaetus gallicus, and the Northern
Goshawk, Accipiter gentilis
Costa, J (1), Infante, S. (2); Rochinha, C.A. (3) ; Veríssimo, C. (1), Fagundes, I.;Gouveia,C. (1),
Habitat and SeasonDifferences between bird collision and
electrocution are apparent in the
analysis by habitat type: coastal
wetlands, with high bird densities are
most important for collision whereas
agricultural patchy land together with
dry cereal fields (pseudo-steppe)
accounts for most deaths by
electrocution.
Mortality is higher in the Autumn
migratory season, both for collision
and electrocution, being lowest in
Winter.
Line and pylon configurationMortality depends also on the pylon and line
configuration. cross-arms in triangular
configuration (angle support) for 15 kV is the
most dangerous for electrocution (3.29
ind./pylon/yr), followed by triangular
configuration (alignment), upper horizontal
disconnectors, vertical disconnectors,
horizontal configuration, and finally delta
configuration (N=5869).
For collision, 3-level lines (Delta
configuration) cause more deaths than 2-
level lines (triangular configuration) (4.2
ind./km per yr vs 2.6 ind./km per yr).
Mitigation and Monitoring
Until now, 243,6 km of medium and
high voltage lines have been subject
to mitigation measures, either for
Collision or Electrocution, in
continental Portugal. There were
employed different kinds of mitigation
devices and they are being monitored
to evaluate their efficiency
Correction Measures Efficiency
The conclusions, shown in the tables below,
are still preliminary for it was not applied a
statistical analysis, due to small sample-sizes,
in some categories. The study is in course and
will be continued. The results of the monitoring
project are being integrated in the Official
guidelines for mitigation of power line impacts
and in the Electrical Company internal Norm.
Some common power line bird mortality mitigation devices:Anti-electrocution
High: 70%-93% reduction in
triangular configuration
Tension clamp Cover
and pin insulator Cover
not evaluated
Avoidance of nesting and
perching
Anti-collision
under study
FBF rotator type
FBF ribbon type
under studyBFD Double spiral red &
white
Low: 4-27% in Delta and
triangular lines
Low: 33 % in triangular lines
BFD simple spiral grey
color
BFD simple spiral red &
white
Triangular configuration
Horizontal disconnector
Vertical disconnectors with
tappings
Delta Configuration
BFD-Bird Flight Diverter; FBF-.Firefly Bird Flapper
Pseudo-steppe Scrubland Agricultural Land Inland Waters
(1)SPEA (2)EDP D (3)Quercus
Threatened species
However, the main concern goes to the
threatened species. rare or endangered
populations such as the Great Bustard,
Otis tarda, The Little Bustard,Tetrax tetrax
die by coliding with power lines. The
spanish imperial eagle, Aquila adalberti,
Golden Eagle, Aquila chrysaetus the
Bonelli’s Eagle, Aquila fasciatus, the Red
Kite, Milvus milvus and the Osprey,
Pandion haliaetus eagles are especially
vulnerable to electrocution in power lines,
and others, such as the Roller, Coracias
garrulus, or the Griffon, Gyps fulvus die
from both causes.
Electrocution (ind./pylon/yr) Collision (ind./km/yr)
Azores Is.
Madeira Is.
Portugal