The productivity may
also turn out to be affected in a direct way for inconveniences in the
areas of nest building provoked by some human activities such as the
opening of new tracks and the achievement of forest works during the
breeding season, or the uncontrolled increase of practices of free time
in the nature.
The decrease of the
productivity (juveniles that fly annually), in spite of having a very
much minor effect on the evolution of the populations, can impede the
rejuvenation of the population if it reaches extreme levels.
Thus the populations
diminish because the number of chicks produced that survive to the
first three years of life, and that therefore obtain the sexual
maturity, are not sufficient to compensate the deaths of the adults.
"Threats and solutions"