Lines and birdlife

Lines have potentially negative effects on birdlife.

While the risk of electrocution characterises low- and medium-voltage lines, Terna’s high-voltage lines can be dangerous in particular because of the risk of collision. This is why in segments of line where birds fly by frequently the Company has installed devices called “dissuaders”, which with their bulk and the noise they produce when wind strikes them make it easier for the birds to notice the lines when they are flying.  

Birdlife dissuaders on the NTG

No. of lines concerned

km of lines concerned
Total No. of dissuaders




In 2008, Terna signed an agreement with the LIPU (the Italian partner of Birdlife International) to carry out a scientific study on the interaction between high-voltage lines and birds.

The project constitutes an important opportunity to study the real interactions between birdlife and the high- and very-high-voltage electric lines of the National Transmissioni Grid for the first time systematically and on a large, national scale. Currently, in effect, the only studies available regard the electrocution of birds that touch two conductors with their wings at the same time, a phenomenon that is characteristic of low- and medium-voltage lines.  

Seven test areas for study were chosen all over Italy on the basis of their particular concentration of wild birds (migration, stays, reproduction). These areas correspond to different environmental categories: wetlands, farmland, mountains, forests, coastal areas are classified as Special Protection Areas (SPAs) and Important Bird Areas (IBAs), and at the same time are characterised by the presence of NTG lines. In 2009, these areas were duly monitored as planned, an activity that will be completed by the end of the first half of 2010.

Nests on the pylon

Terna has also been engaged for some time in experimenting with alternative uses of electric lines for the benefit of biodiversity, including in particular placing boxes on pylons so that birds of prey can build their nests in them. Numerous studies have shown how electric lines constitute observation posts for birds of prey when they are hunting. The birds perch on the pylons because of their height, as well as the protection from predators they provide. 

In 2009, Terna continued to support the “nests on pylons” project in cooperation with the Ornis Italica ornithological association, thanks to which more than 300 boxes suitable for nest-building by birds of prey have been installed in the last few years. Constant monitoring by researchers has enabled them to collect a considerable amount of biological and ethological data and to note a positive effect in terms of biodiversity, constituted by an increase in the kestrel population in Rome. The boxes mounted on pylons were monitored again during the 2009 reproduction season to determine their occupation by kestrels and to collect reproduction data. The nests were inspected from the middle of March to determine their occupation, the size of the clutch, the laying date, and the reproductive outcome.

In May 2009, a first group of 23 nesting places for rollers was also installed on HV pylons, with 60% of the boxes being occupied by the birds for nest-building. The boxes were also occupied by sparrows and scops owls. About 20 scops owls, including three adults, and almost 10 rollers were ringed.

In 2009, Terna also continued to sponsor the “birdcam” project in cooperation with Ornis Italica, which provides for the installation of television cameras on artificial nests in order to follow the reproduction period of the birds online, at and on Terna’s website. The webcam connection also enables researchers to observe the birds from a distance. The activities of the 2009 season began in February, when the cameras were turned on in the nest of Aria (Air) and Vento (Wind), the couple of peregrine falcons that nests on a building of the University of Rome “La Sapienza”.