When birds meet the high-speed rail

The development of high-speed lines, replacing the airplane to reduce CO₂ emissions, poses new ecological challenges. The thousands of kilometers of railways with people travelling at speeds of more than 155 m/h can generate unwanted effects, such as the mortality of birds being run over, a fact that until now had not been analyzed or quantified.

A study published in the journal Frontiers in Ecology and Evolution, has developed a new methodology to study the impact of high-speed trains on birds. For this purpose, a video system has been installed in the cabin of the locomotives during more than 8,700 miles of circulation at speeds of 155-185 m/h.

"This has allowed us to obtain the first ever published estimate of bird mortality by high-speed trains and better understand the behaviors that condition the crash," says Juan Malo, author of the study and researcher at the Autonomous University of Madrid, who has collaborated with Renfe in this LIFE + Zero Impact Project of the European Union, to Sinc.

The results have managed to record 1,090 recordings of birds in front of a train cabin to better understand which ones are more at risk and why. Scientists have obtained much more precise data than could have been obtained a few years ago.

Specifically, they have calculated that a high speed rail underway crosses birds in the vicinity of its frontal every 9 miles of travel, approximately; and runs over a bird every 225 miles driven. "On the Madrid-Levante line, on which the work has been carried out, some 60 birds per kilometer between Madrid and Motilla del Palancar, and 26 birds per kilometer on the stretch between Motilla del Palancar and Albacete, can be run over every year," Malo points out.

Why are they run over?

According to the report, about a third of the rail crossings of the road occur below the catenaries, which corresponds to birds that risk being run over. "In addition, more than 25% of the crossings in front of the train have birds that were perched on the ground, roads or cables of the infrastructure just before the train passes, as protagonists," says the researcher.

The video record has also made it possible to verify that the birds generally react at a distance of 200 to 445 feet of the train, so the train´s speed leaves them little time to escape. "As a result, a small fraction of the birds that can be seen from the front of a train end up dying run over," he adds.

To reduce the run-over of birds, the research team proposes to study procedures so that, first of all, birds do not use elements of the infrastructure, and secondly, systems that decrease the frequency with which animals fly through the risk area through which trains circulate. The latter is a specific objective of the LIFE + Zero Impact project.

"The published data will serve to inform about the environmental impact assessments that are made in the future on the railway tracks to be built, and to guide the design of corrective measures," concludes Malo.