• This course of action is part of the collaboration agreement signed in 2013 between the Government of Aragon and Red Eléctrica de España to learn about and map the flight paths of birds which are potentially susceptible to collisions with power lines
• A method that allows the accurate tracking and monitoring of individuals during their first flights and subsequent movements

As part of the actions included in the Recovery Plan of the Bonelli's Eagle in Aragon, set out in the biodiversity agreement signed with Red Eléctrica de España in 2013, Nature Protection experts and agents of the Department of Agriculture, Livestock and Environment proceeded on 26 and 27 May to fit satellite transmitters onto two new Bonelli's Eagle (Hieraaetus fasciatus) individuals in the region of Baja Aragon. Specialised staff of the Ministry of Agriculture, Food and Environment as well as experts from Red Eléctrica de España also participated in the process.

On this occasion, two young specimens of this endangered species were chosen; offspring of two of the 26 eagle pairs present in Aragon. The use of satellite transmitters will allow the movements of the individuals to be accurately tracked and recorded when they begin their first flights and, later, to get to know the characteristics of their movements during the stages of juvenile dispersal and becoming fully independent. In three, four or five years, crucial data can also be obtained regarding the settlement patterns of the individuals as reproductive specimens in a territory probably close to where they were born. Meanwhile, information about the habitats they frequent and the risks they are exposed to during their lifetime will also be collected.

Included amongst these risks are those of electrocution or collision with electricity lines, the use of poisons or the irrational actions of some irresponsible hunters, all of which may sadly end the lives of some specimens. The information provided by the transmitters is crucial to reduce and even eliminate these risks, or to investigate those which can be considered criminal acts.

Collaboration between the Government of Aragon and Red Eléctrica de España

The transmitter fitted young eagles join the two adult specimens fitted in 2013 as part of the course of actions included in the collaboration agreement signed that year between the Government of Aragon and Red Eléctrica de España.

This agreement includes supporting the Recovery Plan of the Bonelli's Eagle in Aragon and its bird marking programme, through the allocation by Red Eléctrica de España of 48,400 euros over two years (2013-2014). It also addresses the incorporation of Aragon into the Project “Identification, characterisation and mapping of the flight paths of birds that interact with high-voltage power lines” promoted by Red Eléctrica de España in various Autonomous Communities.

This project, commenced as a pilot from 2010 to 2011 in Andalusia and Extremadura, was continued in the first phase between 2012 and 2013 in the autonomous communities of the Canary Islands, Castile and Leon, Madrid, Murcia and Valencia. With the signing of the agreement in November 2013, Aragon joined this initiative, whose main goal is to study and find solutions to the problems of the interactions between birds and power transmission lines, a priority line of work for Red Eléctrica de España over the last two decades.

The aim of the project is to learn about and map the flight paths of birds which are potentially susceptible to collisions with power lines; it is about identifying the areas and flight routes most frequented and used by the birds in their regular movements, which are the ones most associated with situations of potential risk of collision with cables.

The species

Bonelli's Eagle is the most endangered bird of prey in Aragon. It is listed as an "endangered" species and has a Recovery Plan in place since 2011, although recovery work of the species began in the autonomous community in the late 1990s with the start-up of the marking and tracking programme of specimens using different methodologies.

During this time, the programme has so far marked more than 150 individuals, 37 of them with satellite transmitters. The use of this technology has enabled to gain a better understanding of the causes of non-natural mortality of the species, as well as greater knowledge of their areas of juvenile dispersal and use of the territory by adult specimens.

All this data is providing the basis for various research projects carried out at the Universidad Complutense of Madrid and that undoubtedly will shed light on the causes that bring about the endangerment status of the species and on the possible alternatives for their correction.

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