Italian TSO Terna monitors migratory birdlife between the region of Calabria and the island of Sicily in order to assess the impact of a new overhead line (OHL). Two radars were used to collect scientific and measured evidence of the number of birds passing the corridor line, their migratory routes and their flying height.
Although the practice was applied across the Sorgente-Rizziconi OHL, it can be replicated in other similar settings. However, as the practice is expensive and requires the involvement of highly specialised and numerous researchers, it is suitable only for OHLs crossing important habitats.
The impact of OHLs on birds is a field often subject to bias and preconceptions. One of the main difficulties is to assess their impact adequately and evaluate the accuracy of the assessment. For this purpose, Terna developed a radar monitoring study on the Strait of Messina, a bottleneck for sub-Saharian migratory birds. Two watch points on each side of the Strait, one in Sicily and one in Calabria, are operated at the same time by ornithologists. Over the last three years, more than 115,000 passages of migratory birds have been recorded, tracking over 70,000 birds during spring and over 45,000 birds during fall. No collisions or any negative effects on the migratory route have been observed, proving the absence of the new OHL’s impact.
The most relevant added value of the practice is in the scientific and measurable evidence of the migratory routes in relation to OHLs. The long-term data (2014-18) obtained through the radar monitoring programme will allow for a better understanding of migratory routes and the overall impact of OHLs on birds.
Terna, the Italian TSO, developed this practice in collaboration with two ornithologist scientific NGOs (Ornis Italica and MEDRAPTORS) and the eco-ethology laboratory at the University of Pavia.