Phantom of the forest or successful citizen? Analysing how Northern Goshawks ( Accipiter gentilis ) cope with the urban environment

By 2040, roughly two-thirds of humanity are expected to live in urban areas. As cities expand, humans irreversibly transform natural ecosystems, creating both opportunities and challenges for wildlife. Here, we investigate how the Northern Goshawk ( Accipiter gentilis ) is adjusting to urban environments. We measured a variety of behavioural and ecological parameters in three urban and four rural study sites. City life appeared related to all parameters we measured. Urban female goshawks were overall 21.7 (CI 95% 5.13–130) times more likely to defend their nestlings from humans than rural females. Urban goshawks were 3.64 (CI 95% 2.05–6.66) times more likely to feed on pigeons and had diets exhibiting lower overall species richness and diversity. Urban females laid eggs 12.5 (CI 95% 7.12–17.4) days earlier than rural individuals and were 2.22 (CI 95% 0.984–4.73) times more likely to produce a brood of more than three nestlings. Nonetheless, urban goshawks suffered more from infections with the parasite Trichomonas gallinae , which was the second most common cause of mortality (14.6%), after collisions with windows (33.1%). In conclusion, although city life is associated with significant risks, goshawks appear to thrive in some urban environments, most likely as a result of high local availability of profitable pigeon prey. We conclude that the Northern Goshawk can be classified as an urban exploiter in parts of its distribution.

PIGEONS, AN URBAN PATHOGENIC PROBLEM?

The pigeon is a “natural” animal inserted into the artificial environment of cities, who provides a new perspective over the dichotomic concepts of Nature and Culture, traditionally understood as mutually exclusive. Ancient Egyptians began using at least 4000 years ago. The abundance of pigeons is positively related to town's area and population, and independent of the surrounding landscape type. The high densities of this urban exploiter species, alongside people in cities provide opportunity for prolonged and frequent contact between humans and animals. This has important consequences, and the greatest number of human–pigeons conflicts arises in larger towns. People have many casual interactions with pigeons that range from feeding in public parks to handling tamed birds nesting on windowsills. They are both reservoirs and horizontal and vertical vectors of infectious diseases, as well as a source of antigens that provoke allergic diseases.<strong> </strong>Solving the problem of these diseases is a modern and important topic to debate and research. Doing so sustainably should be possible and investigations in this area are necessary for the public safety and health of all, both humans and pigeons alike.<strong> </strong>This study review some diseases and topics concerning pigeons and their zoonoses in the urban environment.