Ancient cities arose not by decree from a centralized political power, as was previously widely believed, but as the outgrowth of decisions made by smaller groups or individuals, according to a new study from researchers at Harvard University, the University of Cambridge, and the University of Edinburgh.

Urbanization changes landscapes and local environments, which can alter the life histories and traits of the creatures living in and around these areas. Studying European blackbirds (Turdus merula), Jesko Partecke and Eberhard Gwinner (Max Planck Institute for Ornithology) discovered certain adaptive traits, that in the long run, could lead to more offspring.