Commencing in 2014, a European LIFE+ project aimed to establish migratory northern bald ibis Geronticus eremita colonies in central Europe, with a common wintering area in southern Tuscany, Italy (see waldrapp.eu for details). The project was preceded by a 13-year study of the ecology and behaviour of the species, and development of translocation methodology (Fritz et al., 2017, International Zoo Yearbook, 51, 107–123). By the end of 2020 the population comprised 158 wild individuals in four breeding colonies. The growth rate became positive in the Kuchl colony (Salzburg, Austria) in 2018 and in the Burghausen colony (Bavaria, Germany) in 2019. Colonies in Baden-Württemberg (Germany), and Carinthia (Austria) are still being established.
The main translocation method is human-led migration. A group of up to 32 zoo-born chicks per season are raised by human foster parents. After fledging the birds undergo a training programme to follow two microlights co-piloted by the foster parents. From mid August this migration leads in flight stages of c. 220 km per day from the breeding sites north of the Alps over c. 1,000 km to the wintering site in southern Tuscany, where the birds are released. During 2014–2019 a total of 154 birds were released. No release occurred in 2020 because of the COVID-19 pandemic.
Microlight piloted by a foster parent leading northern bald ibises to the wintering site in southern Tuscany, Italy. Photo: Waldrappteam Conservation & Research.
First-year survival of the released juveniles is 0.73, significantly higher than the 0.31 first-year survival of released juveniles in the Spanish Proyecto Eremita (Böhm et al., 2020, Oryx, 55, 934–946). We attribute the high survival rate of released birds in our project to the complex pre-release training and low loss during the human-led migration. Reproduction in the released population has increased steadily. During 2014–2020, 151 birds in 61 nests fledged in the wild, a mean fledging rate of 2.47 per nest. This is double the fledging rate of 1.23 per nest in the last remaining wild population in Morocco. The high fledging rate in the LIFE+ project reflects the high-quality feeding habitats in the breeding areas north of the Alps.
A recent population viability analysis indicates that the reintroduced population is close to sustainability but that further releases and management will be needed. This will be under a second European LIFE project, run by Zoo Vienna with partners from Germany, Austria, Italy and Switzerland, aiming to establish further migratory colonies in Austria, Switzerland and northern Italy, and a total population size of > 350 individuals.
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