Bird-friendly design of power lines

In Norway, energy consumption is anticipated to increase 20-60% by 2040. Ever increasing parts of this demand is covered by development of renewable energy, like wind power. The fast rate of energy development leads to an increasing need for electric power transmissions and thus construction of new powerlines. All powerlines, however, entail environmental costs, and it is a challenging task to identify the negative impacts on birdlife and construing ways to minimize these. The main objective of BIRDPOL is to develop predicting tools for optimal routing of powerlines from an environmental perspective and assess technical solutions to minimize negative impacts on birdlife. Three clearly defined work packages have been developed to achieve the main objective; 1) Identification of bird flight patterns at marked vs unmarked wires using a mobile avian radar. Bird diverters (markers) are devices installed on the earth wires of power lines to make the lines more conspicuous to birds. But how efficient are such tools in reducing the risk for collisions?, 2) Identify characteristics of high-risk areas for bird collisions, using advanced statistical tools. Where and when is collision risk enhanced and in which circumstances should measures to prevent collisions be considered?, and 3) Assess how bird flight behaviour is influenced by landscape features and power lines using mobile avian radars. Do birds prefer to use some areas more than others, and can this be linked to specific landscape features and placement of powerlines? This knowledge will be used to inform during the planning phase for new powerlines. Data collection on bird activity using NINA?s avian radars started in spring 2018 in Vinjeøra, Trøndelag county and continued in 2019 (autumn) and 2020 (spring and autumn). Here, Statnett constructed a new powerline in connection with the development of a new wind power plant at Fosen, Trøndelag, which has a section marked with bird diverters. Data were also collected in control sites in Sogn & Fjordane county (spring 2019), and Trondheim (autumn 2019) and Tydal (autumn 2020), Trøndelag. The analyses on the effectiveness of wire markers showed clear behavioural responses of birds to the presence of the wire markers, which suggest that markers can indeed reduce the collision risk. Our results show that birds reacted to these markers by avoiding flying close to the powerline, flying at higher heights and increasing their height from further away when crossing the powerline, crossing safely above the powerline. These results have been partially published in a scientific article published in 2020, presented in two scientific conferences in Iceland (2020) and Switzerland (2022), and communicated to a wider audience during diverse meetings in 2020, 2021 and 2022. In addition, a new analysis including a larger dataset has been completed and the manuscript is in preparation. Importantly, the results of the new analysis support the findings in the published article. In BIRDPOL, all observations of bird fatalities caused by powerlines registered in various databases have been compiled and stored in a database managed by NINA since 2019, which is updated twice a year. As of April 2022, NINA?s database has ca. 13100 observations (4496 georeferenced). To predict mortality hotspots, advanced statistical methods that constitute state-of-the-art in this field were developed in BIRDPOL to integrate these data with estimates of bird abundance and environmental covariates. First, we have published a new methodology to integrate count data and predict species abundances across space (In Press). This step is critical to estimate the distribution and abundance of birds in Norway, which is one of the base information for predicting the mortality hotspots. Second, to predicts hotspots of mortality along the network of powerlines, we developed a novel method to integrate such diverse data sources on bird casualties and bird distribution of abundance as well as environmental factors such as topography, geomorphology, climate, and powerline density. This technical development was very complex and we anticipate having it published by the end of 2022. The potential of our methods attracted the interest of organisations from France, Belgium, and the UK during the presentation of the method at a scientific conference in April 2022. Analysing the vast amount of data collected by the avian radar is computational demanding. To understand flight patterns in relation to landscape features and power lines, we are using advanced statistical techniques (INLA framework). Results give information on which landscape features shape bird movements in the region. A manuscript on this is in preparation. BIRDPOL has received good coverage in scientific meetings and the media and popular-science seminars. Dr. Diego Pavón-Jordán conducted the analyses (January 2019-December 2021). BIRDPOL was led by researchers at NINA, with Statnett and NVE (end: April 2022).

BIRDPOL results are relevant for the scientific community and industry: -We make available (FAIR principles) a database of all records of bird casualties due to powerlines in Norway. -We produced statistical advancements by developing two new methods to integrate (i) abundance data from monitoring programmes (published), and (ii) detection/non-detection and presence-only data to improve inferences from ecological data. -We apply these to predict mortality hotspots along powerlines, providing useful information for future planning and identifying areas where existing powerlines should be equipped with markers. An ongoing analysis with data at finer scale will provide further details. This has attracted international attention. -Mitigation measures applied by Statnett (markers) can be effective. Birds respond to the markers, reducing collision risk. -Preliminary analysis of flight patterns in relation to landscape did not show effect of powerlines.

In order to achieve policy goals on addressing climate change challenges and securing electricity supply, it is necessary to significantly increase electricity transmission capacity. Statnett has estimated investment costs of approximately 40-55 billion NOK over the period 2016-2020. All power lines, however, entails environmental costs. Due to the fast rate of energy development and the increasing need for electric power transmissions, it is a challenging task to identify the negative impacts on birdlife and construing ways to minimize these. Hence, it is paramount to develop practical and functional tools, measures or products, to reduce bird mortality or disturbance, in order to avoid delays in the consenting processes and to streamline the construction or upgrading phases. All flying birds risk colliding with power lines, including several red-listed and economically important species. Hence, focus on environmental and management issues connected to power lines has received a growing interest among environmental and energy management authorities, but there is a great need for well-defined and well-functioning mitigation measures to reduce impact of power lines on birdlife. The knowledge is considerable when it comes to what bird species are most vulnerable in terms of colliding with overhead wires. However, significant knowledge gaps still exist in connection to efficiency of mitigation measures in order to reduce species-specific collision risks, and to characteristics of collision hotspots in the landscape. The main aim of the proposed project is to reduce ecological consequences of bird collisions and habitat alterations through innovative, well-targeted, predictable and cost-effective solutions related to wire marking and routing of power lines. The main utility value concerns application of this novel knowledge to reduce negative impacts of utility structures on birds and reduce conflict levels in construction of power lines.