image: A peregrine falcon (Falco peregrinus) overlooks Chicago, Illinois. view more
Credit: Image courtesy of Derek Zaraza (photographer)
A study suggests how competition between bird species affects bird distribution in cities. Urbanization affects many species worldwide, but it remains unclear why certain species persist in urban habitats while others do not. Paul Martin and Frances Bonier examined how competitive interactions between bird species affect the birds' ability to survive and reproduce in cities. The authors compiled breeding occurrence data on nearly 300 bird species in 260 cities worldwide. Species were classified according to their propensity for breeding in cities, a measure of their degree of adaptation to urban environments, and whether they were dominant or subordinate in interactions with closely related species. Among urban-adapted species, dominant species were more widespread than subordinate species in cities where both types coincided. Dominant and subordinate species were equally prevalent in cities where their ranges did not overlap. The difference between dominant and subordinate urban-adapted species was largest in economically developed countries, whereas in developing countries, dominant and subordinate species were equally prevalent even when their ranges overlapped. According to the authors, the results suggest that asymmetric competition enables behaviorally dominant species to take advantage of urban habitats and exclude equally well-adapted subordinate species, and that economic development exacerbates this phenomenon.
Article #18-09317: "Species interactions limit the occurrence of urban-adapted birds in cities," by Paul R. Martin and Frances Bonier.
MEDIA CONTACT: Paul R. Martin, Queen's University, Kingston, CANADA; tel: 613-533-6598; e-mail: pm45@queensu.ca
###