Costs and benefits of formation flight in birds

The Northern bald ibis (Geronticus eremita) is an indigenous migratory bird in Europe. After being extinct in on the continent for over 300 years, a European conservation project led by Waldrappteam is trying to reintroduce a stable migrating population. Every year chicks of Northern bald ibis are hand-raised by two foster mothers and taught to follow a paraplane. Through this method, it is possible to show the birds the migratory route from the breeding site (low Germany/Austria) to the wintering site in Tuscany. The conservation project offers a special opportunity to study different aspects of migration flights, something that is very challenging with free migrating birds. For example, many aspects of formation flight during long-distance migrations are still poorly understood. Even less studied is how the birds exchange their position inside a V-formation (e.g. from a more energy-demanding frontal position to a less energy-demanding back position) and whether social relationships among individuals may play a role. Previously these aspects were out of bounds because of the difficulty to keep track of all the individuals in a free-flying flock. 

The human guided migration gives the chance to address these questions, as it is possible to monitor all the birds in the formation. During the flights, every bird is equipped with customized GNSS data loggers with the purpose of collecting and storing satellites’ raw data. The subsequent data post-processing allows obtaining cm-level precision in the calculation of the birds’ relative position in the flock.


FWF Project P-30620, LIFE Northern Bald Ibibs LIFE+12-BIO_AT_000143


Johannes Fritz, Waldtrappteam
Bernhard Voelkl,
University of Bern, Switzerland, & Waldtrappteam
Elisa Perinot
Ortal Rewald, University of Veterinary Medicine, Vienna, & Waldrappteam
Leonida Fusani