The Northern Bald Ibis used to be a migratory bird that left the breeding area in autumn to overwinter in suitable habitats. This was true especially for those populations that used to live in the pre- Alps. Although Northern Bald Ibises can cope with low winter temperatures, there isn´t enough food because of the frozen soil; single individuals (Shorty, Elmar) managed to endure a winter in the north.
Our Northern Bald Ibises show the urge to migrate from mid of August on. This urge is genetically fixed. As observed within inexperienced young birds, the migration route or rather the direction isn´t inherent. They learn the position of a proper wintering area from experienced fellows. Because since nearly 400 years there are no more migrating Northern Bald Ibises in Europe, this information cannot be passed on any more.
To found new, migrating colonies it is absolutely necessary to supply the future wild birds with this information. Therefore, up to 16 nestlings of zoo populations are hand- raised by two human foster parents and imprinted on them. From now on the birds follow their foster parent everywhere, even if the person is sitting in a microlight and flying ahead of them. Therefore, the foster parents resume the role of the experienced fellows and can show the young birds the way to a proper wintering area. In 2011, it turned out for the first time that this tradition really is passed on among the birds, and a year later the first naturally raised bird that once learned the position of the wintering area from experienced fellows acted as lead bird himself. This standardized process is necessary for every new colony. Every bird needs to be guided from the breeding area to the wintering area once; they find the way back independently.