The northern bald ibis is one of the world rarest birds, and has been placed on the critically endangered list. It disappeared from central Europe in the 18th century.
Breeding programmes aimed at reintroducing the birds to the wild have to find a way to show them the migration path to follow, which is where two foster moms in yellow and an ultralight aircraft come in.
Their "Reason for Hope" project is funded by the EU with the aim of leading the birds 1000 kilometers across the Alpine divide and teach them to migrate from Germany to Italy for the winter winter.