No, never. Peregrines only hunt birds in the air, never birds on the ground, in buildings or in cages. Moreover, even if they did change their hunting technique, they would never be able to capture caged birds because their legs are too thick to fit them through cage bars. There are however four species capable of eating caged birds in Barcelona: magpies, yellow-legged gulls, kestrels and cats.
No, never. Human beings are a potential enemy of Peregrines and for this reason they always keep a safe distance away. Moreover, Peregrines only feed on birds they can trap in the air, never birds on the ground, in buildings or in cages.
No, never. The Peregrine Falcon shows territorial behaviour and because of this a pair of Peregrines will never tolerate the presence of other Peregrines in their territory. If we consider that a breeding territory of a Peregrine Falcon covers a minimum of 3km2 and the urban area of Barcelona is 79km2, it can be easily seen that the city could never hold more than 26 pairs.
No, the chief aim of their reintroduction is to recover a species which had bred here until its extinction in the early 1970s due to human pressures. But we should not forget that Peregrines do eat pigeons, and in the area around which a pair of Peregrines lives, the population of pigeons is reduced, both because some are eaten and because their presence frightens them away.
Peregrines have been breeding in European cities since at least the Middle Ages, when they lived and bred in the bell towers of cathedrals. Peregrines live anywhere in the world wherever they can find food (medium-sized birds) and cliffs or vertical walls in which to nest and survey their territory. The cities of the past and the present provide them with a large number of high buildings which serve the same function as natural cliffs. Moreover, the city -today more than ever- provides Peregrines with more food than most "natural" habitats. We should remember that large numbers of birds live in today's cities (pigeons. starlings, collared doves, parakeets, etc) which form part of the Peregrine's diet and which feed on the remains of food they find scattered around. Cities, thus, are a more favourable ecosystem for Peregrines than forests. Forests do not offer as much food as cities, and trees also make it difficult for Peregrines to see birds, and therefore, hinder their capture. Moreover, Peregrines never breed in trees.
The Peregrine didn't become extinct due to natural causes (lack of food, habitat destruction, competition with other species, etc) but rather because of human causes. It was people who caused their extinction by killing the last pair and their offspring in a period when the law not only permitted this but also actively encouraged it. It is therefore our responsibility to restore the natural heritage we once destroyed.
They are very different species. The city is an ideal habitat for Peregrine Falcons: this is not the case with eagles and wolves. Peregrines find it very easy to live here, with a city's abundant food and high buildings to build their nests. In contrast, eagles, if ever the case were to arise, would find neither large branches to build their nests, nor sites in which to build them, nor rabbits to eat. As for wolves, their movement would be severely hindered by traffic, they would have nowhere to build their dens and they would not be able to find their preferred prey. Thus, releasing Peregrines in the city -an optimum medium for them- makes perfect sense, while the city is an inhospitable medium for many other species.
Yes, Peregrine Falcons formed an important part of the natural heritage of the city of Barcelona before disappearing due to human pressures. Their extinction represented thus a great loss for the natural heritage of the city. The restoration of our lost natural heritage like the restoration of architectural and historical heritage is the responsibility of all our society and, in consequence, of its public representatives. In summary, it is the responsibility of our society to restore the natural heritage lost due to our negative actions.
The reintroduction technique consists of releasing Peregrine chicks in the city so that they adapt to life here. As occurs with Peregrine chicks hatched outside the city, some chicks die (around 50% during their first year) while others disperse far from the territory where they hatched. Because of this, a large number of chicks are released in order to ensure that -once those which die or leave the city have been discounted- enough still remain to establish a nesting population.