Since disturbance by humans is one of the most frequent causes for nesting failure among Imperial eagles, the BSPB has organised permanent protection of the most endangered nests during the breeding season. This has increased the success rate among breeding pairs by 30% per year.
Volunteers who are well trained and exceptionally dedicated to the cause spend the entire breeding season watching the eagles and keeping detailed logs of their behavior - when do the adult birds feed the chicks, when the male and the female take turns, and any substantial changes of the weather conditions. On many occasions the guards have saved the nest from failure by kindly asking any perpetrators to leave the region in order to avoid disturbing the birds. “Usually people who are unaware that there are globally endangered birds nearby cause the disturbance”, Vayno Angelov, one of the guards of an Imperial eagle nest, said. “I have seen a fisherman seeking shelter from the rain, or groups of noisy hikers, or some specific agricultural operation involving more noise. Then I ask in a most well-meaning way the people to leave and the adult birds who had flown away return to the nest and resume caring for the eggs. Otherwise the eggs will have cooled or overheated in a few hours and this will be the end of the brood”, the guard adds.
There are cases when the guards have prevented the cutting down of the tree with the nest, although such a tree is protected by law and the fine is BGN 10,000, as is written on a signboard displayed in a visible location. There have been a few cases of eaglets falling from the nests as well due to a storm or due to an unsuccessful first attempt at flying. Then the guard intervenes and rescues the young bird from land-based predators, by returning it to the nest and giving him a second chance at successful flight.