The Bonellis Eagle, Sierra de Grazalema

Bonelli’s Eagle, Icon of the Serranía

Bonelli’s Eagle (Hieraaetus fasciatus) master of our skies.

If you were to search for an emblematic species which would define the importance of the Serranía de Ronda  and the Sierra de Grazalema for wildlife, then the Bonelli’s Eagle (Hieraaetus fasciatus) would be the definitive and unequivocal choice.

Among the rarest species of raptor in Europe, the Bonelli’s Eagle has perhaps, for the moment, its highest breeding density in the world right here in the Serranía de Ronda!

With a wingspan of up to 1.8 meters the Bonelli is a medium sized eagle and although it is known to sometimes nest in trees, in the Serranía its preference is for rocky crags and faces. The pairs form lifelong and all year round partnerships staying in or close to their breeding territories throughout the year.

Usually nests are re-furbished during late December and early January. During this period pairs can be witnessed indulging in flight-play with one, normally the male, dropping a stick and the other retrieving it before it reaches the ground! The first egg is laid during February and although a clutch of 3 is possible the most usual is for 1 to 2 eggs.

Incubation normally takes around 40 days and usually a single young is fledged after a further 60/65 days, exceptions where 2 young are fledged normally relate to older and more experienced adults, these older birds seemed to have learnt to supply more food for the successful rearing of all their offspring.

These eagles are extremely agile flyers and one of the most aggressive. Protection of the nest site during the breeding season is a spectacle that can provide the fortunate observer with a life time experience. The male will often pursue and sometimes inflict fatal injuries on much larger birds such as Griffon Vultures who venture too close to the nest. I have often seen unfortunate Griffons retreat from areas minus a few feathers!

Unlike many other eagle species, the Bonelli’s are capable of flying-down their prey and over long distances. Most large raptors avoid long distance pursuit in order to save energy, but these eagles, once giving chase, will continue to fly-down prey over considerable distances. Hare, Rabbit, Partridge and other large birds form the largest part of their diet, although some reptiles are also taken.

The current status of this magnificent and spectacular eagle is officially listed as being under danger of extinction. So it is essential we afford them the highest possible protection. Although some of their nesting sites are close to populated areas, they remain intolerant of human disturbance, so close observation should be avoided at all times.

Also they tend to have defined hunting routes and are sometimes seen daily on these routes, so not only do their nest sites need urgent protection, but also their feeding areas. Their continued presence in the area depends on us and our willingness to afford them the special protection they need and deserve. Our skies would be the poorer without them.

It has been estimated that an annual total exceeding 15,000 birdwatchers visit the Serranía and without doubt this eagle is a star attraction. So the Bonelli’s Eagle is important to the local economy! Any unwanted or unsustainable developments that adversely impact on the numbers of this threatened species of eagle i.e. Los Merinos Golf, will by definition have a very real and negative affect on the area’s tourism, economy and people.

If you would like a guide day tour of the Serranía de Ronda to see Bonelli’s Eagle, Griffon Vulture, and other bird species of the Serranía, we recommend Wildside Holidays – Grazalema. Some locations of Bonelli’s Eagle may be difficult to reach, and for ecological reasons many locations are a closely guarded secret.