Adult mortality 

The adult mortality is the percentage of adult individuals of the reproductive population that have died in a certain period.  The individuals considered are those missing or restored of one year for other in the controlled territories.

This is one of the most determinant demographic parameters because the disappearance of an adult, an experienced animal with aptitude to reproduce, has much more negative effects for the population than the loss of a brood or the death of a juvenile.

The strategy of predators is that of little breeding, in return, but, of living through many years. If the mortality of adults increases abnormally, then the population is in danger.

Principal causes of mortality

In Catalonia the power line electrocution is at present the principal cause of mortality of adult individuals of Bonelli´s Eagle.

Eagle dead for collision with the cables (Photo: Joan Real)

Although direct persecution (shooting, poisoning, and trapping) has happened to be the second factor of death, the number of eagles that die for this cause in Catalonia continues being the same as several decades ago, which means that this problem has not diminished.

It is worrying to see how in diverse private hunting areas the chasing to the eagles continues, even using traps and poisons, accusing them of being responsible for the decrease of the hunting species.

Whereas, in other areas of Spain the direct persecution continues being the first cause of death of the eagles. We must stand out that in some zones of the Sout-East Spain is very common the use of poisons, while in Catalonia this practice is not much employed and of nearly all the eagles found dead the cause of death has been electrocution or shooting.


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