The Experts below are selected from a list of 3696 Experts worldwide ranked by ideXlab platform
May, Roelof Frans - One of the best experts on this subject based on the ideXlab platform.
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Do birds respond to spiral markers on overhead Wires of a high-voltage power line? Insights from a dedicated avian radar
'Elsevier BV', 2020Co-Authors: Pavòn-jordàn Diego, Stokke, Bård Gunnar, Åström Jens, Bevanger, Kjetil Modolv, Hamre Øyvind, Torsæter Ellen, May, Roelof FransAbstract:Growing human population demands the expansion of the energy transmission grid. Power lines represent a major death hazard for many species, especially birds. Addressing such a human-wildlife conflict requires detailed knowledge of how species use the aerial space and how they react to mitigation measures, such as flight markers. Here, we use a dedicated avian radar to study birds’ flight behaviour at marked and unmarked sections of a power line in Norway. We investigate the effect of Wire marking on the density of bird tracks, multidirectionality, perpendicularity and turning angle at increasing distance from a power line as well as the maximum turning angles and track height. In addition, the avian radar allowed us to compare flight behaviour between daytime and night-time. The density of bird tracks was lower during the daytime (when markers are visible) compared to night-time (markers are not visible). Furthermore, bird tracks (i) were more directional during daytime, especially at the marked section, (ii) were less perpendicular to the power line at the marked compared to the unmarked section, and (iii) performed more pronounced turning angles at the unmarked compared to the marked section. Moreover, tracks’ maximum turning angle was largest at the unmarked section and the average track height was greater at the marked section of the power line. Our findings provide new correlative evidence of changes in birds’ flight behaviour induced by flight markers on a power line’s Earth Wire. Furthermore, we highlight the adequacy of dedicated avian radars to assess the efficiency of conservation interventions mitigating the impacts of overhead energy infrastructure (power lines, wind turbines) on the use of the aerial space by animals.publishedVersio
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Do birds respond to spiral markers on overhead Wires of a high-voltage power line? Insights from a dedicated avian radar
2020Co-Authors: Pavòn-jordàn Diego, Stokke, Bård Gunnar, Åström Jens, Bevanger, Kjetil Modolv, Hamre Øyvind, Torsæter Ellen, May, Roelof FransAbstract:Growing human population demands the expansion of the energy transmission grid. Power lines represent a major death hazard for many species, especially birds. Addressing such a human-wildlife conflict requires detailed knowledge of how species use the aerial space and how they react to mitigation measures, such as flight markers. Here, we use a dedicated avian radar to study birds’ flight behaviour at marked and unmarked sections of a power line in Norway. We investigate the effect of Wire marking on the density of bird tracks, multidirectionality, perpendicularity and turning angle at increasing distance from a power line as well as the maximum turning angles and track height. In addition, the avian radar allowed us to compare flight behaviour between daytime and night-time. The density of bird tracks was lower during the daytime (when markers are visible) compared to night-time (markers are not visible). Furthermore, bird tracks (i) were more directional during daytime, especially at the marked section, (ii) were less perpendicular to the power line at the marked compared to the unmarked section, and (iii) performed more pronounced turning angles at the unmarked compared to the marked section. Moreover, tracks’ maximum turning angle was largest at the unmarked section and the average track height was greater at the marked section of the power line. Our findings provide new correlative evidence of changes in birds’ flight behaviour induced by flight markers on a power line’s Earth Wire. Furthermore, we highlight the adequacy of dedicated avian radars to assess the efficiency of conservation interventions mitigating the impacts of overhead energy infrastructure (power lines, wind turbines) on the use of the aerial space by animals
Henrik Broseth - One of the best experts on this subject based on the ideXlab platform.
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bird collisions with power lines an experiment with ptarmigan lagopus spp
Biological Conservation, 2001Co-Authors: Kjetil Modolv Bevanger, Henrik BrosethAbstract:The number of ptarmigan (Lagopus lagopus and L. mutus) killed along three power-line sections through colliding with the overhead Wires was recorded over a 6-year period in a subalpine habitat in southern Norway. The effect of an experimental removal of the power-line Earth Wire (common neutral) was evaluated on one of the power-line sections, by comparing the number of mortalities found before removal with the number found afterwards. The two other power-line sections in the same area were used as control sections. The number of collisions was approximately halved after the lower Earth Wire was removed, thus confirming the expectation that there is a connection between the number of overhead Wire levels (vertically) and the collision rate. The results from this and earlier studies indicate that a reduction in overhead Wire levels has a general positive effect by reducing the collision rate. The power companies should develop alternative engineering designs and critically assess constructing power lines with continuous Earth Wires.
Haddad Abderrahmane - One of the best experts on this subject based on the ideXlab platform.
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Computation model for ground potential and current distribution in ground impedance measurements at high-voltage towers
IEEE, 2007Co-Authors: Harid Noureddine, Griffiths Huw, Haddad AbderrahmaneAbstract:In this paper, a numerical model is developed to determine the Earth impedance of transmission towers, which can incorporate the effect of the variations of the tower resistances along the line, the end effect of the terminating substation and the effect of the auxiliary current electrode. The model is based on the computation of the potential at the test tower and the potential at any point on the ground surface, including the contributions from all the towers. The distribution of the test current between the Earth Wire and towers is computed by a numerical procedure which solves the matrix equations of a circuit model of the transmission line Earthing system. The Earth impedance curves computed with this model are in good agreement with those obtained from a geometrical model of the line Earthing system and obtained using commercially-available software
Pavòn-jordàn Diego - One of the best experts on this subject based on the ideXlab platform.
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Do birds respond to spiral markers on overhead Wires of a high-voltage power line? Insights from a dedicated avian radar
'Elsevier BV', 2020Co-Authors: Pavòn-jordàn Diego, Stokke, Bård Gunnar, Åström Jens, Bevanger, Kjetil Modolv, Hamre Øyvind, Torsæter Ellen, May, Roelof FransAbstract:Growing human population demands the expansion of the energy transmission grid. Power lines represent a major death hazard for many species, especially birds. Addressing such a human-wildlife conflict requires detailed knowledge of how species use the aerial space and how they react to mitigation measures, such as flight markers. Here, we use a dedicated avian radar to study birds’ flight behaviour at marked and unmarked sections of a power line in Norway. We investigate the effect of Wire marking on the density of bird tracks, multidirectionality, perpendicularity and turning angle at increasing distance from a power line as well as the maximum turning angles and track height. In addition, the avian radar allowed us to compare flight behaviour between daytime and night-time. The density of bird tracks was lower during the daytime (when markers are visible) compared to night-time (markers are not visible). Furthermore, bird tracks (i) were more directional during daytime, especially at the marked section, (ii) were less perpendicular to the power line at the marked compared to the unmarked section, and (iii) performed more pronounced turning angles at the unmarked compared to the marked section. Moreover, tracks’ maximum turning angle was largest at the unmarked section and the average track height was greater at the marked section of the power line. Our findings provide new correlative evidence of changes in birds’ flight behaviour induced by flight markers on a power line’s Earth Wire. Furthermore, we highlight the adequacy of dedicated avian radars to assess the efficiency of conservation interventions mitigating the impacts of overhead energy infrastructure (power lines, wind turbines) on the use of the aerial space by animals.publishedVersio
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Do birds respond to spiral markers on overhead Wires of a high-voltage power line? Insights from a dedicated avian radar
2020Co-Authors: Pavòn-jordàn Diego, Stokke, Bård Gunnar, Åström Jens, Bevanger, Kjetil Modolv, Hamre Øyvind, Torsæter Ellen, May, Roelof FransAbstract:Growing human population demands the expansion of the energy transmission grid. Power lines represent a major death hazard for many species, especially birds. Addressing such a human-wildlife conflict requires detailed knowledge of how species use the aerial space and how they react to mitigation measures, such as flight markers. Here, we use a dedicated avian radar to study birds’ flight behaviour at marked and unmarked sections of a power line in Norway. We investigate the effect of Wire marking on the density of bird tracks, multidirectionality, perpendicularity and turning angle at increasing distance from a power line as well as the maximum turning angles and track height. In addition, the avian radar allowed us to compare flight behaviour between daytime and night-time. The density of bird tracks was lower during the daytime (when markers are visible) compared to night-time (markers are not visible). Furthermore, bird tracks (i) were more directional during daytime, especially at the marked section, (ii) were less perpendicular to the power line at the marked compared to the unmarked section, and (iii) performed more pronounced turning angles at the unmarked compared to the marked section. Moreover, tracks’ maximum turning angle was largest at the unmarked section and the average track height was greater at the marked section of the power line. Our findings provide new correlative evidence of changes in birds’ flight behaviour induced by flight markers on a power line’s Earth Wire. Furthermore, we highlight the adequacy of dedicated avian radars to assess the efficiency of conservation interventions mitigating the impacts of overhead energy infrastructure (power lines, wind turbines) on the use of the aerial space by animals
Nigel A Clark - One of the best experts on this subject based on the ideXlab platform.
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the response of common terns sterna hirundo to power lines an assessment of risk in relation to breeding commitment age and wind speed
Biological Conservation, 1996Co-Authors: Ian G Henderson, Rowena H W Langston, Nigel A ClarkAbstract:Abstract Common terns breed within the industrial complex at Shotton Steel Works, North Wales. Each journey between the breeding colony and the main feeding areas on the Dee estuary requires the terns to negotiate two spans of power lines. Here we investigated the risk of collision with power lines in relation to the time demands on adults, the age of birds and wind speed. Systematic observations were made of terns journeying to and from the estuary during four phases of the breeding season (courtship, incubation, nestling and juvenile). Casualty surveys of the ground beneath the power lines were also completed, and in order to quantify the potential removal rate of bird casualties by predators, bird corpses were placed underneath the power lines and recounted after two, five and 14 days. There was a greater than three-fold increase in the frequency of combined journeys made by terns from courtship to the nestling phase and this increase coincided with an increase in the proportion of adult terns which passed under or between the Wires of the power lines. Terns also flew closer on average to the top Earth Wire during the nestling and fledging phases than during the courtship or incubation phases. Juvenile terns flew consistently closer to Wires than adults with most juvenile crossings being Common terns are agile birds and suffered only low rates of direct mortality through collisions with power lines. However, the demands placed on parent birds during the breeding season caused a significant increase in their vulnerability to collision. This is a factor which has not previously been studied and has implications for a wider range of species.
