The reintroduction project could be helping the expansion of the Spanish Imperial Eagle towards NE Spain.
Last June, for the second time in few weeks, an inmature Spanish Imperial Eagle Aquila adalberti was observed in the area where the Black Vulture Reintroduction Project in Catalonia is based (Boumort-Alinyà). Few days ago, another (or maybe the same bird) has been located in Navarra region, also in the Pyrenean area. These observations are not the first one for the area (even in Catalonia) but they coincide with a n increasing number of sightings and longer stays of Iberian Black Vultures in the area, some of them comming from Central Spain (at least 2 ringed birds from Madrid colonies).
It is well knonw that Imperial Eagles usually feed on carrion, and so, eagles use vultures as information source to find food. Juvenile dispersal areas of both Black Vultures and Imperial Eagles are largely the same, as they show maps of satellital banded eagles and vultures (Grefa and others).
Even being cautious due to the few information about this issue, we can preview a positive and absolutely unexpected effect of the Black Vulture reintroduction project in the Pyrenees on the expansion of the Spanish Imperial Eagle towards the North and East of the Iberian Peninsula, where the species, as did Black Vultures, disappeared more than a century ago. A new population of vultures in the Pyrenees increases the probability that dispersal immatures vultures, born in the Iberian traditional colonies, appear in the region and following them, also juveniles Spanish Imperial Eagles.