First nest with three Bonelli eagle young birds in ten years in Catalonia


Bird ringing, carried out by the Conservation Biology Group of the University of Barcelona, in collaboration with the Mountain support group, enabled the identification of this exceptional finding in the natural park of Cap de Creus.

Bird ringing, carried out by the Conservation Biology Group of the University of Barcelona, in collaboration with the Mountain support group, enabled the identification of this exceptional finding in the natural park of Cap de Creus.


Since 1980, the Conservation Biology Group at the University of Barcelona has been a benchmark for research into the ecology of Bonelli's eagle.

Since 1980, the Conservation Biology Group at the University of Barcelona has been a benchmark for research into the ecology of Bonelli’s eagle.

The Conservation Biology Group of the Faculty of Biology and the Biodiversity Research Institute of the University of Barcelona (IRBio), in collaboration with the Mountain support group, detected a nest with three Bonelli’s eagle young birds (Aquila fasciata) in the Natural Park of Cap de Creus. This is an exceptional finding, since only three young birds had been detected in five occasions in birds around Catalonia, more than ten years ago. Since 2005, the reproduction of this endangered species has decreased, and the average per year is less than a bird per couple.

Bonelli’s eagle breeding is rare in Catalonia, where these birds use to lay two eggs or even one only. Factors affecting high egg laying are unknown, but they can be related to an important abundance of food in the environment, with the “reproductive pause” during some seasons and singular features of the animals. Food abundance in the environment during the previous period to the egg laying allows the female to reach a good body condition and lay more eggs, as well as breeding the young birds successfully.

The nest belongs to a Bonelli’s eagle couple present in this area for two years. Actually, in 2014 they breed for the first time, and in 2015, but it has been three years the couple did not have young birds. The birds weigh enough now to fly.

A distinguished team in the study and conservation of the Bonelli’s eagle

The Conservation Biology Group (UB-IRBio) is a distinguished group in the research on ecology of the Bonelli’s eagle and in providing solutions to improve its preservation. This species, named after the ornithologist Franco Andrea Bonelli –who documented it for the first time in 1819- is considered an endangered species in the European continent.

Recovering the population in Catalonia

At the moment, about 80% of the European populations of the Bonelli’s eagle are in the Iberian Peninsula. Catalonia is the only place where the eagle population is recovering, as well as in the Balearic Islands, where it was re-introduced.

In particular, out of the 85 recorded couples in Catalonia in 1980, there were only 65 in 2000. After that, the population underwent a recovery progressively, until reaching the current 77-79 couples, six of them in Girona.

The Catalan Government is working on the preservation of the eagle in Catalonia, and is now carrying out the monitoring of this species’ population, which suffered a decline during the eighties and nineties, reaching historical minimum figures. Over the last years, the population was stabilized and colonization has been observed in some territories. The Catalan Government is taking part in this action considering the environment where the birds live and minimizing human activities that can disturb them and put them in danger. Also, other actions the Generalitat is taking to guarantee the presence of potential prays are improvements in the habitat. Also, in collaboration with electricity companies, it participates in reducing the impact of these structures regarding the death of the species.

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