Birds stricking aircraft cause substantial economic loss wordwide and more worryingly, human and wildlife fatalities. Civil aviation authorities are really concern about this problem and try to find effective measures to avoid fatal bird strikes.
Since 2000, there have been 12 planes crashed due to birds and 15 people lost their life. Although many species of birds can collide with airplanes, only three species were involved in these accidents: griffon and cinereous vultures (Gyps fulvus and Aegypius monachus) and white storks (Ciconia ciconia). All the crashes involved general aviation aircraft, while none were recorded in commercial aviation. Besides, although public and media attention is often pointing commercial aviation, most occurred outside airport boundaries.
These low numbers reveal that, in comparison with the millions of flights that operate annually, mortal accidents due to bird crashes are very rare, but it's undoubtedly necessary to do the best to try to reduce them. With this aim, 16 researchers from European and American centers and lead by the Doñana Biological Station and Miguel Hernández University have studied the flight patterns of vultures and storks making use of GPS tracking.
Estas bajas cifras revelan que, en comparación con los millones de vuelos que surcan nuestros cielos anualmente, los accidentes mortales por choques con aves son muy raros, pero sin duda es necesario hacer todos los esfuerzos posibles por intentar reducirlos. Con esta finalidad, un equipo de dieciséis investigadores procedentes de centros americanos y europeos y liderado desde la Estación Biológica de Doñana y la Universidad Miguel Hernández, ha estudiado gracias al seguimiento GPS, los patrones de vuelo de buitres y cigüeñas.
They tracked 92 griffon vultures from four Spanish populations, 15 cinereous vultures from Spain and Portugal and 103 storks from Spanish and German populations. This provide a large amount of data that showed that birds have more flight activity during the central hours of the day (between 10:00 and 16:00) and between March and September. This is fundamentally due to the fact that they are soaring birds that need thermal currents to fly efficiently, so they concentrate their activity in the periods of greater insolation and availability of rising air. It is precisely then, when more serious accidents are registered.
In addition, the researchers observed that, contrary to popular belief that attribute exaggerated flight heights to many birds, the species studied spend most of their time flying below 1,300 meters above the ground. "This implies that small aircraft, which by law must fly below 900 meters above the ground, are forced to share space with vultures and storks, increasing the risk of collision", explains Eneko Arrondo, researcher at the Doñana Biological Station and main author of the research.
The applicability of the study is clear. Part of these results was already presented at the 2nd Aviation and Fauna Forum organized by AESA (State Agency for Air Safety) in January 2020, where they were very well received by industry experts. According to the researcher, "these results can not only be useful for a possible legislative change on the top flight height of non-commercial aviation, but also serve to give clear recommendations to pilots on which periods to take preventive measures such as flying as high as possible or to low the speed to reduce the kinetic energy of a possible impacts". This work is a clear example of how ecological studies, in addition to serving to preserve biodiversity, can have immediate applicability to reduce significant economic losses and risks for people.
Arrondo, E., García?Alfonso, M., Blas, J., Cortes?Avizanda, A., De La Riva, M., Devault, T. L., ... & Donazar, J. A. Use of avian GPS tracking to mitigate human fatalities from bird strikes caused by large soaring birds. Journal of Applied Ecology https://doi.org/10.1111/1365-2664.13893