Herranz, J., Falcao, L., Hervás, I., Mata, C., Santamaría, A.E., García de la Morena, E. y Malo, J.E. Effectiveness of an anti-bird strike tubular screen in a high-speed railway. 2020 IENE International Conference. Abstract book. Évora: Infrastructure & Ecology Network Europe. 2021, Vol. 1.3.1, Num. 4, pags. 40-41. ISSN 978-972-778-182-9
A High speed trains run at speeds over 250 km/h, and birds which coincide in their trajectories are thus unable to avoid crashing or being affected by turbulence provoked by them. The result in the second case can be also death, since destabilized birds may end up colliding with the catenary, other railway structures or the ground. As a consequence, any bird crossing a high speed railway (HSR) through the gap between the ground and the 5.3m high power wire, or among the catenary cables, is under risk and mitigation should aim to avoid such cross-flights. Traditional mitigation in areas of high interest for birds and in viaducts crossing them has been the installation of protection screens similar to those implemented for noise abatement. The height of such screens is strongly restrained by their aerodynamic resistance to wind and to the piston effect of passing trains, since they are built of continuous or drilled plates. Thus, they are un-frequently more than 2.5m tall and they do not cover but a small part of the risk gap. Taller designs are not feasible due to structural limitations of viaducts, increased costs of maintenance and hazard for trains in case of breaking. A new design of anti-bird strike screen has been built and its effectiveness tested along a 400m section of HSR in regular use in the proximity of Santa Cruz de la Zarza (Madrid- Valencia line, Spain). The location was selected for its high bird mortality after one-year seasonal monitoring along 10 km of railway, and it consists of a section on an embankment ca. 6-10m high. The prototype is built of independent vertical poles 5.5m tall at 2m intervals in each side of the track so that in front-view the screen has a density of one pole by meter. Even if not a continuous barrier, it is designed under the assumption that birds (at least larger ones) will fly upwards to avoid it and cross the HSR safely above it. After construction in 2018, the bird mortality monitoring has been replicated, and we present here the data obtained in the location of the screen and in two adjacent areas of the same length and railway topography. Results support a significant decrease (chisquared
test p<0.05) of bird mortality in the section covered by the screen, at least for large-bodied species: 8 death birds (20.0 individuals/km) were found in the protected section while the two control sections had 22 and 18 fatalities (55.0 and 45.0 individuals/km respectively). Moreover, all carcasses but one rock dove (Columba livia) found in the screen section corresponded to passerines, while in control sections 25 birds of the rock dove size or larger were found (31.2 individuals/km), outstandingly among them Bubo bubo.
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