When a city's pigeon density exceeds its tolerable limit (300-400 pigeons/km2 on average, although this can vary according to the city’s features), measures need to be established to control their population numbers.
Pigeon overpopulation, as in Barcelona’s case, according to the latest census, where there are some 85,000 pigeons in the city area, can end up as a public health problem, given that some birds may suffer from illnesses or carry pathogens that can be passed on to people (zoonosis).
Furthermore, pigeons are harmful to our architectural heritage, street furniture and vegetation. They also cause problems in grain-storage sites and gardens (they spot newly planted seeds and eat them). They can give rise to agricultural problems in some areas, where crops are very close to cities, seeing that some move to these places for feeding.
City residents are becoming used to such situations in the areas pigeons are having the worst effects on. This has been causing a reduction in perceived risks and numbers of incidents reported to the authorities, making it harder to quantify the true presence and impact of pigeons in these areas.
We ought to bear in mind that pigeons, where they are properly controlled (suitable population number, ideal location and good state of health) represent added value to the beauty of any city. Their flying and cooing embellish squares and gardens and provide entertainment for children and serenity for adults.
Like dogs and cats, pigeons have not invaded cities; it is we, the city’s residents, who have encouraged them to live among us at one time or another.
Rock doves (Columba livia) are the feral ancestor of the semi-domesticated pigeon (Columba livia var. domestica).
Barcelona City Council’s Wild Fauna Ecopathology Service (SEFaS), aims to respond to the problem of pigeon management in Barcelona's urban area by supplying maize grain laced with nicarbazin to control pigeon breeding there.
Nicarbazin for controlling the number of urban pigeons is marketed with maize grain and covered over with an edible silicon layer so the nicarbazin stays on the maize even when it is handled or gets wet.
The studies made conclude that availability of food is the factor that best explains the presence of pigeons in a certain place and that the situation is caused by people feeding them.
Work document prepared by the Wild Fauna Ecopathology Service (SEFaS) at the Autonomous University of Barcelona’s Faculty of Veterinary Medicine.