IMPROVED POWER LINE INTERACTION WITH BIRDLIFE (EN12, EN13, EN14)
Power line markers
One of the fauna impacts deriving from the construction and operation of power lines involves the possibility of birds colliding with cables and, more rarely, being electrocuted.
The signing of a collaboration protocol with the Nature Conservation Institute (now Nature Conservation Institute and Biodiversity), on the impacts on Birdlife of high voltage lines, identified the power line sections considered to have or potentially have impact.
In the wake of this process, over the course of 2006 measures to minimise impacts on birds were implemented by marking sections on the Ferreira do Alentejo-Ourique 150kV power line. Nearly 16,355 devices to reduce bird collisions were installed, of the BFD (Bird Flight Diverter) type, as indicated in the figure below.
Figure 14 – Marking of the Ferreira do Alentejo – Ourique power line (detail of BFD on right)
Other sections of the power line identified in the protocol will be marked in 2007, and the effectiveness of the marking methods meanwhile adopted will be evaluated.
Control measures
Likewise in the area of Birdlife protection and per the indication of environmental studies, of environmental assessment processes or periodical maintenance activities, the main activities undertaken to make the national transmission grid compatible with the presence of storks have been the following:
- · Installation of nesting platforms, eventually accompanied by nest transfers;
- · Assembly of simple and expeditious devices to prevent storks from perching on insulator strings (initially small crosses with buoys and crossed wires and, more recently, small fans or windmills);
- · Placement of plates over insulators (little used option).
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Figure 15 – Evolution of Birdlife nesting control measures
All these actions were carried out with the authorisation of the Nature Conservation Institute, with a view to reducing situations of bird death by collision or electrocution. The aim has also been to minimise the number of incidents caused by storks on operational power lines, thus improving service quality.
With the implementation of some simple measures it has therefore been possible to significantly increase the number of existing nests on pylons of the national transmission grid (in 2006 nearly 1,300 nests were inventoried) without affecting service quality.
Figure 16 – Evolution of the number of stork nests and the rate of incidents in NTG power lines
Figure 17 – Black stork
The year 2006 saw an increase in the number of recorded incidents, compared to the previous year. This circumstance may be related to an increase in the stork population in habitats crossed by national transmission grid power lines. In some areas flocks of birds in considerable number have effectively been observed. Although they do not nest on the power line pylons, they use them as perch sites.
Bonelli eagle study and conservation
During the process to evaluate the environmental impact of the Tunes—Estoi 150kV and Sines—Portimão 3 400 kV power lines, significant impacts on Birdlife were identified, due to the power lines’ proximity to Bonelli eagle (Hieraaetus fasciatus) nests. The main impact derives from the possibility of the birds colliding with power lines, especially when hunting, for adults, and in the flight learning phase for juveniles.
For three years various compensatory measures will be implemented to increase food availability, improve the nesting habitat and study as best as possible the eagles’ interaction with power lines, and to assess the effectiveness of the implemented measures. Details of this action can be examined more closely by reading the case study.
Figure 18 – Bonelli eagle (photo provided by the International Douro Natural Park)
Also in the context of Bonelli eagle conservation activities, noteworthy is the sponsorship granted to the project to conserve woodland populations of this species in Portugal, under the LIFE Nature Programme of the Iberian Birdlife Studies Centre (CEAI). This project specifically aims to:
- · Lower the mortality of adults and juveniles, and increase the productivity of pairs, so as to positively influence the population dynamic of the Bonelli eagle;
- · Improve habitat management by creating more favourable environmental conditions for the presence of this project’s target species, and consequently of other priority species;
- · Monitor the Bonelli eagle population covered by the project;
- · Involve the various social players who act in territorial management (including farmers, hunters, forest managers, officials from central/regional/local government and businesspersons) in conservation actions, granting them a significant and valued role, encouraging them to play an active role in the conservation of biodiversity in general and the species in particular.