In southern Spain, 257 northern bald ibises birds were released during 2004-2011 in the context of a project evaluating the efficacy of different controlled release methods.
In 2008 reproduction in the reintroduced population was confirmed for the first time, and since then the ibises have bred every spring, with a slow increase in numbers.
On 2 November 2016, whilst monitoring migration of the Griffon Vulture Gyps fulvus, the authors observed a group of six northern bald ibises reaching the Moroccan coast from Europe. This is the first confirmed sighting of northern bald ibises successfully reaching Morocco after crossing the Strait of Gibraltar from Spain.
The only other observation was of a single Spanish-ringed northern bald ibis on 24 May 2007, in Merja Bargha.
These observations suggest that the reintroduced ibises are expanding their home range southwards, which could indicate a progressive adaption of the population.
With the Spanish population increasing, the crossing of the Strait of Gibraltar, in both directions, will probably become more regular, and could have far-reaching consequences for both the Moroccan wild population and for the reintroduction programme in Spain.
Muñoz, A.R. & Ramírez, J. 2017. Reintroduced northern bald ibises from Spain reach Morocco. Oryx 51: 204-205.