35 Northern Bald Ibises guided by ultralight planes just completed the 2300 km migration from project Waldrappteam in Germany to Proyecto Eremita site in south Spain.
Waldrappteam
I think following these projects, other zoos and bird parks in Spain, Portugal, south and central France and Greece could start free-flying colonies of Waldrapps. Everything depends from an enthusiastic person coming up, but the project is very practcially possible. Waldrapp is globally endangered, large and native to Europe. They can overwinter in these regions, given their wintering in Italy, and regular wintering of other large insect-eating birds: introduced Sacred Ibis, Cattle Egrets, and Stone Curlews.
Balearics would be especially good. They have no predatory birds like Eagle Owls and large eagles. Tourism industry can use Waldrapps an aditional attraction, like reintroduced waterbirds in S'Albufera nature reserve. Waldrapp used to live in Balearics according to historic falconry books* There are two zoos in Mallorca: Safari Zoo Mallorca and Natura Parc, and wild bird reserve S'Albufera. Maybe one would be interested in freeflying Waldrapps?
Some zoos and bird parks already have Waldrapps. Zoo Doue la Fontaine has rocky cliffs, which it famously uses for exhibits. Why not have Waldrapps flying free? Le Jardin aux Oiseaux in Upie is also close to rocky areas and just 60 km from the proven historic occurence of Waldrapp** Réserve Africaine Sigean is on the Mediterranean coast, again close to rocky areas, which could be a natural nesting place. In south and central France, there are also Parc des Oiseaux in Villars les Dombes, Réserve zoologique Calviac, Parc Animalier des Pyrénées, and Zoo du Bassin dArcachon. In Spain there are: Canada de los Pajaros at La Puebla del Rio, Selwo Aventura, Oasys Mini Hollywood in Tabernas and Zoo Barcelona. In Portugal, Zoo Lisboa and Park & Zoo Santo Inácio. In Switzerland, south of Alps there is Falconerie Locarno, again close to a number of rocky cliffs and old buildings to nest.
I think actually ecological requirements of Waldrapp can be misunderstood. Released Waldrapps raise larger broods in farmland in Central Europe than wild in Morocco. They historically nested as a commensal of man in towns in Europe and the Middle East. Possibly Waldrapp could be subtly trained to roost and nest on buildings. Maybe urban habitat can be a refuge from eagle owls and hunting?
*Evidence of the historic presence of the Northern Bald Ibis (Geronticus eremita) in Spain
https://www.researchgate.net/public...orthern_Bald_Ibis_Geronticus_eremita_in_Spain
**Presence of the Northern Bald Ibis Geronticus eremita (L.) during the Holocene in the Ardèche valley, southern France
https://www.researchgate.net/public...olocene_in_the_Ardeche_valley_southern_France