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Tracked Bonelli’s Eagles reached Africa for the first time

The recent migration of two young Bonelli’s Eagles across the Strait of Gibraltar to Morocco shows an unknown dispersive movement in this species. This confirms once again the importance of North Africa to the Iberian raptors.

Bonelli’s Eagle ‘Zahara’ passing through the Strait of Gibraltar
Bonelli’s Eagle ‘Zahara’ passing through the Strait of Gibraltar (Santi Villa / Spainbirds Nature Tours).

The Bonelli’s Eagle (Aquila fasciata) is usually resident across its breeding range. However, some immature birds sometimes make large dispersive movements. With a few exceptions now and then, European birds are not known to cross the Strait of Gibraltar to Africa in significant numbers. Even when some birds cross the Strait, we don’t know where they disperse as they mix with the North African population.

Satellite-tracking Bonelli’s Eagles

Recently, two Bonelli’s Eagles were fitted with GPS transmitters in Spain have crossed the Strait of Gibraltar to Africa. They are the first birds of this species to be tracked from Europe to Africa. The two Bonelli’s Eagles, both males, are from different origin and once in Africa they followed different paths.

The first bird known as Zahara was born in 2014 in the captive breeding centre of Bonelli’s Eagle headed by Jean-Claude Mourgues in the French department of Ardèche.

The second bird known as Turón was born in 2015 in a wild nest in the province of Granada (Andalusia, Spain). Both were released in the west of Madrid region, one of the reintroduction areas of LIFE Bonelli project.

Zahara: the adventurous eagle

After leaving his release site in Madrid in mid-September 2014, Zahara headed south and wondered a few days between different places in Andalusia. From his last place in Almeria, he continued south-east without stopping to cross the Strait of Gibraltar (photo above by Santi Villa). He became the first Bonelli’s Eagle for which crossing the Strait was confirmed and followed by satellite tracking.

On 23 September, he is already in northern Morocco and in four days he arrived to Algeria and shortly after to Mauritania. Zahara continued his journey to Senegal from where he decided to return to southern Mauritania. By then he had crossed five countries and had traveled more than 4 400 kilometers (map below).

Movement of the Bonelli’s Eagle ‘Zahara’ (Iglesias & Álvarez 2016, Quercus)
Movement of the Bonelli’s Eagle ‘Zahara’ (Iglesias & Álvarez 2016, Quercus)

Turón preferred western Morocco

After different dispersive movements in the Iberian Peninsula (first to Galicia, back to Madrid and then to Portugal and Andalusia, see map), Turón decided to head south and cross the Strait on 8 October 2015.

Some days later, he found a suitable place to spend the winter between the Moroccan cities of Rabat and Casablanca. On his journey, Turón traveled more than 3 500 km in total (map below).

Movement of the Bonelli’s Eagle ‘Turón’ (LIFE Bonelli project)
Movement of the Bonelli’s Eagle ‘Turón’ (LIFE Bonelli project)

The full story of these Bonelli Eagles was published in the following article in Quercus magazine:

Iglesias, J.J. & Álvarez, E. 2016. Sorprendentes águilas perdiceras: dos ejemplares cruzaron el Estrecho. Quercus (361): 30-33.

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