Back to the Case Study Hub

The Spanish Imperial Eagle is a European endemic species that was close to global extinction in the 1960s, as a result of poisoning, electrocution from electricity towers and habitat degradation. The improvement in its conservation status has been achieved through a concerted programme of LIFE Nature projects.

The most important drivers to the success of these conservation measures have been the initial research that was conducted on the main threats to the species, the coordinated action that took place through national and regional action plans, as well as the wide implementation of key measures. These included the modification of electricity structures, legal protection and enforcement to reduce poisoning, and habitat management measures that engaged all key stakeholders.

No new measures are urgently required for this species as it is now recovering in all its range states, but continued conservation management is necessary to support its populations in the Iberian Peninsula.

Challenges addressed

As a naturally long-lived species with relatively low breeding success rates, its populations are particularly susceptible to increases in rates of adult mortality. The main threats to the species currently result from electrocution, accidental and deliberate poisoning and habitat change. In a study that examined the death of 267 Spanish Imperial Eagles between 1989 and 2004, 91.7% of the causes of mortality (where the cause of death could be determined) were of human origin, with electrocution and poisoning being by far the most common causes of death.

Other pressures include habitat fragmentation as a result of deforestation for agriculture and timber, and suitable habitat in breeding and dispersal areas has also declined as a consequence of urban development and other land-use changes. Breeding success has also been affected by declines in rabbit populations as a result of myxamatosis in the 1950s, and more recently viral haemorrhagic disease. This has been exacerbated by changes in the management of hunting estates to favour larger quarry species, such as deer and boar, rather than rabbits and partridges. Human disturbance (eg tourism) of nesting birds can reduce breeding success and the ingestion of lead shot embedded in the flesh of prey items may be a problem in certain areas in the long term as it can result in heavy metal bioaccumulation. The installation of wind turbines and solar power plants also pose an increasing threat for the conservation of the species.


Main objectives of LIFE projects addressing the Imperial Eagle in the 90s included the monitoring of the population, its distribution, mortality, nesting areas and breeding success in order to identify and subsequently avoid human disturbances and provide supplementary feeding to breeding pairs when necessary. Specifically, an objective was to reduce disturbances through power lines. Awareness raising of landowners and hunters, whose actions could directly or indirectly harm the target species was also an objective. More recent objectives include combatting illegal poisoning of the species.

Planned and implemented measures

A major effort has been made to reduce the electrocution of birds on power lines. The LIFE projects led to agreements with public electricity companies on modifying power lines to reduce their threat to birds. As a result, from 1991-1999, 14,370 dangerous electric towers were modified, considerably reducing deaths from electrocution although not all mitigation measures have proved to be totally effective for this species. Furthermore, by 2008, a Spanish Royal Decree was published governing technical regulations for high tension power lines to protect birds. Further, the ‘Alzando el Vuelo’ (Flying High) programme of SEO/BirdLife and the private land protection of Fundación de Amigos del Aguila Imperial (FAAI) engaged national authorities, local communities and private landowners in conserving and protecting the Spanish Imperial Eagles’ habitat. Under this, agreements have been signed with landowners who manage their land sympathetically for the species. This has created an extensive network over 54 municipalities with nearly 50% of breeding pairs covered by such projects. Work is on-going to raise awareness and support on private land where the species breeds, including improving habitat management.

Other conservation measures that have been taken include a supplementary feeding programme to mitigate the effects of rabbit decreases, which has significantly increased breeding success. Nest surveillance has also reduced disturbance and improved reproductive success.

Stakeholder involvement

Since 1987, national and regional governments have been implementing conservation measures for the Spanish Imperial Eagle, in collaboration with several organisations, including WWF and SEO/BirdLife Spain and municipalities. In the early 1990s, the five Regional Governments in the eagle’s range came together with the Directorate-General for Nature Conservation of the National Environment Ministry to agree a Coordinated Recovery Plan for the species, and a set of linked LIFE projects in three stages across the five regions was developed. The first set of projects started in 1992, with the third finishing by 2000. Each region published a species action plan (SAP), i.e. recovery plan, for the species and a National Conservation Strategy was also produced, which was formally approved in July 2001. Different Regional Authorities and national government departments established a LIFE programme Steering Committee. From 1997, the group became known as the Imperial Eagle Task Force. Engagement with private landowners and the electricity supply sector has also been important.

Key achievements and impacts

There is little doubt that the conservation measures taken to date have been the main cause of the recovery of this species in both Spain and Portugal. The Spanish population is estimated to have increased by 135% from 2001 to 2012 and the species recolonised Portugal in 2003. According to the most recent published data, 358 pairs were counted in Spain in 2012, giving an overall estimate of c.370-380 pairs, and the Portuguese population was estimated at 11-18 pairs in 2013; so the current total population is around 1,100 individuals.

Without such actions the Spanish Imperial Eagle may well have become extinct. However, the recovery may also have been aided by changes in social attitudes towards birds of prey, and recoveries in the species' main prey (rabbits) from disease outbreaks. Attitudes to the Spanish Imperial Eagle have significantly improved and effective measures were established to increase the European rabbit populations through management agreements with land owners and hunting managers. It should be noted, however, that progress has not been made in relation to the use of lead shot among hunters despite the availability of other (more expensive) type of ammunition.

Costs and financing

The total costs of the conservation are not known as key funding sources are not fully documented. The LIFE Nature Programme has played a major role in the species recovery, in particular through the 23 projects listed in Annex 1. Together these amount to at least €26 million over the period 1992 – 2007. This constitutes by far the main source of funding for the conservation of the species.

It is estimated that nearly €2.6 million were spent on the mitigation of bird electrocution in Andalucía during 1992–2009. A total of €12 million were leveraged from the National Government and Community funds such as the European Regional Development Fund to fund modification of power lines in the 2004-2007 period.

Funding sources for the ‘Alzando el Vuelo’ (Flying High) programme, which started in 2006, came from Adif (Administrador de Infraestructuras Ferroviarias, Spanish state owned railway infrastructure manager), Fundación Biodiversidad (multidisciplinary team currently under Ministry for Ecological Transition) and Obra Social Caja Madrid. Funding to conserve the species has also been sourced from other bank entities and NGOs.

Lessons learned

The key targeted conservation measures that led to the improvements

  • Research that provided a reliable understanding of the species’ ecology and the key factors that were causing its decline.
  • The development of SAPs with coherent and coordinated programmes of measures.
  • The species was a focus of a great deal of conservation effort, involving national/regional and NGO conservation organisation, and engaged land owners and other important stakeholders.
  • Protection of a large proportion of the species’ key sites in the Natura 2000 network and other protected areas.
  • Concerted and carefully targeted efforts to reduce the key causes of adult mortality (as such long-lived species are particularly vulnerable to this), namely electrocution and accidental and deliberate poisoning.
  • Habitat conservation measures, to increase the area of suitable habitat and breeding success rates.
  • Targeted reintroduction measures to reinforce critically small sub-populations and to overcome barriers to recolonisation such as habitat fragmentation and the species’ low levels of dispersal.

Factors that supported the conservation measures

  • The availability of continuous funding that could be specifically targeted towards the species’ conservation needs, in particular the LIFE Nature programme action grants.
  • The species’ risk of global extinction and iconic status helped to increase awareness of its plight and win over widespread support for conservation measures.
  • Generally changing social attitudes towards birds of prey and increasing recreational interests in bird watching and nature provided a supportive background for the conservation measures.

Factors that constrained conservation measures

  • Increasing urbanisation and infrastructure development, habitat change and fragmentation.
  • Limitations on available funding for habitat conservation measures such as through agri-environment schemes from Rural Development Programmes, and limited impacts from some agri-environment schemes due to their design and low levels of compliance.
  • Increasing recreation and tourism in some areas, leading to increasing nest disturbance.
  • Natural diseases in the species’ prey population.

Examples of good practice, which could be applied to other habitats and species

  • The development and implementation of coherent conservation measures targeted to the key factors affecting the species’ population status (i.e. adult mortality) at sufficient scale to have population level impacts.
  • The creation of legal instruments that result in effective measures such as ensuring that new electricity installations are designed to minimise the risk posed to birds of prey.
  • Engagement of all key stakeholders in the conservation of the species.
  • Development of a programme of habitat conservation measures through management agreements with landowners.

Reference information

The information presented here is based on the work done as part of the European Commission study on identifying the drivers of successful implementation of the Birds and Habitats Directives (under contract ENV.F.1/FRA/2014/0063), carried out by the Institute for European Environmental Policy, BirdLife International, Deloitte, Denkstatt, Ecologic, ICF Consulting Services and PBL Netherlands Environmental Assessment Agency. The information and views set out in this case study are those of the authors and do not necessarily represent the official views of the Commission.

Their sources include:

BirdLife International (2015) European Red List of Birds. Office for Official Publications of the European Communities, Luxembourg.

BirdLife International (2018) Species factsheet: Aquila adalberti. Downloaded from on 01/12/2018.

Bisson, I A, Ferrer, M and Bird, D M (2002). Factors influencing nest-site selection by Spanish Imperial Eagles. Journal of Field Ornithology 73: 298-302.

Castaño, J P (ed.). 2005. El águila imperial ibérica (Aquila adalberti) en Castilla- La Mancha. Estatus, ecología y conservación.

Deinet, S, Ieronymidou, C, McRae, L, Burfield, I J, Foppen, R P, Collen, B and Böhm, M (2013) Wildlife comeback in Europe: The recovery of selected mammal and bird species. Final report to Rewilding Europe by ZSL, BirdLife International and the European Bird Census Council. London, UK: ZSL.

EEA/ETC-BD (undated) Aquila adalberti. European Environment Agency / European Topic Centre on Biodiversity Factsheet.

ETC-BD (2018) Member State Article 12 reports on Aquila adalberti, as compiled by ETC-BD on EIONET.

Fernández, M, Oria, J, Sánchez, R, Gonzalez, L M and Margalida, A (2009) Space use of adult Spanish Imperial Eagles Aquila adalberti. Acta Ornithologica (Warsaw) 44(1): 17-26.

González, L M and Margalida, A (Eds.) (2008) Biología de la conservación del Águila Imperial Ibérica (Aquila adalberti). Organismo Autónomo de Parques Nacionales. Ministerio de Medio Ambiente y Medio Marino y Rural., Madrid.

González, L M and Oria, J (2004) Águila Imperial Ibérica Aquila adalberti. In: Madroño, A., González, C., Atienza, J.C. (ed.), Libro Rojo de las Aves de España, pp. 145-151. Dirección General para la Biodiversidad and SEO/BirdLife, Madrid.

González, L M, Arroyo, B E, Margalida, A, Sánchez, R and Oria, J (2006). Effect of human activities on the behaviour of breeding Spanish Imperial Eagles (Aquila adalberti): management implications for the conservation of a threatened species. Animal Conservation 9(1): 85-93.

González, L M (1996) Action plan for the Spanish Imperial Eagle (Aquila adalberti). In: Heredia, B, L Rose, M Painter (Eds.): Globally threatened birds in Europe: Action Plans. Council of Europe and BirdLife International. Strasbourg, 21 p.

Junta de Andalucia (2015). Programa de actuacion del Aguila Imperial Iberica. Años 2015-2019. Available online at: Last accessed on 28 November 2018.

Margalida, A, González, L M, Sánchez, R, Oria, J and Prada, L (2007) Parental behaviour of Spanish Imperial Eagles Aquila adalberti: sexual differences in a moderately dimorphic raptor. Bird Study 54(1): 112-119.

Muriel, R, Ferrer, M, Casado, E, Madero, A and Calabuig, C (2011) Settlement and successful breeding of reintroduced Spanish Imperial Eagles Aquila adalberti in the Province in Cadiz (Spain). Ardeola 58: 323-333.

Sánchez, B, González, L and Barov, B (2008) Action plan for the Spanish Imperial Eagle Aquila adalberti in the European Union.

Silva, J P, Houston, J, Toland, J, Jones, W, Eldridge, J, Thorpe, E, Bacchereti, S and Thévignot, C (2014) Long-term impact and sustainability of LIFE nature, Luxembourg. 57 p.

Pain, D J Meharg, A A, Ferrer, M, Taggart, M and Penteriani, V (2005) Lead concentrations in bones and feathers of the globally threatened Spanish imperial eagle. Biological Conservation 121: 603-610.