The Catalan population of Bonelli’s Eagle would face a high risk of extinction in the medium-term if not for arrival of individuals from other regions

A new scientific research carried out by the Conservation Biology Group, with the collaboration of researchers from the National Center for Scientific Research (CNRS, France) and research centres from Spain, Portugal and South Africa, analyses key vital rates (productivity - average chicks flying per pair included in the study -, adult and pre-adult mortality, etc.) in Western Europe Bonelli’s Eagle populations between 1990 and 2009. This enabled to know demographic relationships among populations and to understand population dynamics in Western Europe, the area where we find more than the 80 % of the European population of this endangered species in decline.

		The research reveals that eagle populations are not isolated in the Iberian Peninsula. On the contrary, there are some individuals moving around and some populations act as sources of individuals, whereas the Catalan population of Bonelli’s Eagle would suffer an important decrease due mainly to a high adult mortality (11,1% in Catalonia, whereas in Cadis – Andalusia – is only the 5%) so this population is critically endangered and its survival probably depends on their arrival of individuals from other regions. However, the Catalan population has kept stable during the last years and, in addition, presence of eagles with a reproductive behaviour has been confirmed in three territories, as well as eagles with a territorial behaviour in a fourth one. In this sense, in recent years the time that a territorial eagle is replaced by a new one when it disappears is only few days, and the proportion of adult individuals replaced by adult individuals has increased. This suggests that there is an important amount of non-territorial individuals moving around that are able to replace territorial eagles, and these probably come from other populations from the Iberian Peninsula.
The scientific paper published in Ecological Monographs suggests that there is an important amount of non-territorial individuals moving around that are able to replace territorial eagles, and these probably come from other populations from the Iberian Peninsula.
En àrees rurals abandonades i actualment molt forestals, les poblacions d'àliga perdiguera es troben al límit de l’extinció.

Demographic differences between Bonelli’s Eagle populations within Europe are due to human activity and environmental, geographical and climatic conditions. Most populations in Northern Iberia, where rural areas are under populated and tree-covered, are at high risk (high adult mortality rate, decreased fertility, etc.). However, in Southern Iberia populations, who live in warmer areas where traditional activity continues, demographic parameters are better.

The research published on Ecological Monographs was supported by Miquel Torres Foundation, Vilafranca del Penedès (Barcelona) and Barcelona Provincial Council. It has been possible thanks to a long and intense collaboration among researchers, managers and nature benefactors which enabled to carry out a long-term monitoring, a basic tool to design biodiversity conservation policies from a broad, effective and contemporary perspective. Published on May 2013, this paper has already had an important impact in several websites about science and conservation, such as   phys.org, raptorpolitics.org.uk, redOrbit, revistaquercus.es, U.Porto and Wildlife Extra, among others.

For further information:

• Hernández-Matías, A., Real, J., Moleón, M.,  Palma, L., Sánchez-Zapata, J.A., Pradel, R., Carrete, M., Gil-Sánchez, J.M., Beja, P., Balbontín, J., Vincent-Martin, N., Ravayrol, A., Benítez, J.R., Arroyo, B., Fernández, C., Ferreiro, E.,  & García, J. 2013. From local monitoring to a broad-scale viability assessment: a case study for the Bonelli's Eagle in western Europe. Ecological Monographs, 83:239–261. http://dx.doi.org/10.1890/12-1248.1