(Photo: Joan Real)

The productivity is the number of chicks produced by pair and year. It refers to the chicks that have ended up by flying and that therefore have been raised successfully. The production of young eagles is vital for the maintenance of any animal population.

Likewise, the productivity is a warning parameter of the quality of the territories of the reproductive pairs. If it is low, it indicates that there are factors that alter the survival of the eagles and that his territories are less and less suitable. The factors that affect in a more direct way in the productivity are the quantity of available food and the inconveniences provoked by certain human activities.

Principal causes of decrease of the productivity

a) Factors that make the lay unviable

- The adults' death or the presence of sexually immature specimens in the pairs.

- The absence of food.

- The cold and rainy winters.

b) Factors that affect negatively during the incubation or breeding of the chicks

- The absence of food, which provokes the abandonment of the nest on part of the female and consistently the death of the chicks for famine.

- Human Inconveniences in the nest: the activities that imply a long or regular permanence in the areas of breeding and those that place on crags make the eagles feel very insecure, and they do not hesitate to leave the nest. The most aggressive are: jeeps, motorcycles, mountain bikes, climbing, flying devices, trekking, photographs of nests, etc.

Go to "The demography of the eagle"