Migration completed!
Newsletter 30/08/2019
On August 26 we and 29 young Northern Bald Ibises arrived at the WWF reserve Laguna di Orbetello in southern Tuscany. It was the sixth human-led migration in the current LIFE+ project, the 14th altogether and, moreover, by far the most successful one.
The journey started on August 14 2019 in Heiligenberg in Baden-Württemberg. In the course of seven stages we crossed the Alps, the Po Valley and the Apennines, covering a distance of around 900 km and surpassing the performance of earlier flights in several ways. When crossing the Alps, the flight formation reached a height of 2900 meters above sea-level and thus flew approximately 300 meters higher than ever before. Supportive winds accelerated the flight of both birds and aircrafts from the usual 45 km/h up to 77 km/h. Above the Apennines, strong up winds carried both birds and aircrafts up to 2300 meters, who reached ascent rates of up to 9 meters per second.
Apart from the 29 hand-raised young birds, further 37 fledged in the two breeding areas Burghausen (Bavaria) and Kuchl (Salzburg), which is 42% more than in 2018! These juveniles are growing up without human intervention and will be guided by their conspecifics to the wintering area in Tuscany. Currently, 58 birds from these two breeding areas are staying north of the Alps. From mid-September they will migrate to Tuscany. Thus, the total number of juveniles born in this season sums up to 66 birds. Furthermore, in spring 2019, a subadult bird returned to Überlingen at Lake Constance for the first time since the local extinction of the species 400 years ago. This strengthens our hope that from 2020 an increasing number of Northern Bald Ibises will breed at the shores of Lake Constance, too.
The positive progress of this year’s human-led migration was even more important as all birds were equipped with miniaturized devices during the flights. These devices recorded the position, the wing beat frequency and the flight speed of each single bird in high precision. Four birds were also equipped with adhesive electrodes to measure their heart rate during the flight. This enables us for the first time to calculate the energy consumption of migratory birds depending on the flight technique and their position within the flight formation. The two PhD students Elisa Perinot and Ortal Rewald are evaluating this unique dataset in the course of an Austrian research project to gain new insights into the function and energetics of the formation flight in migratory birds.
Picture: After their arrival, the two foster mothers Anne-Gabriela Schmalstieg and Helena Wehner are welcoming their fosterlings. They both did a great job with a lot of commitment. It was the first time for Helena to raise and train Northern Bald Ibises. Anne, on the other hand, was on duty it for the sixth - and last - time. Even though she won’t raise and train young birds anymore, we hope she’ll stick with the project in the context of another task area.
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