Human initiation of synurbic populations of waterfowl, raptors, pigeons and cage birds

Abstract

A common generalization is that wild birds somehow manage to colonize urban areas without human support, which is often true. This paper focuses on a different and probable, though not rare, course of events, when some urban bird populations emerge with immediate human support, by intentional introductions or escape from captivity. This alternate mechanism may be responsible for settling the very first colonizers directly into a strongly urbanized habitat. Such "pioneers" might later be followed by "surplus individuals" moving into cities from the neighbouring natural populations. Eventually, birds of local origin may constitute a prevailing part of the locally developed synurbic population, thus, overshadowing the early genetic contribution of the very first pioneers. Yet the latter individuals might be important as initiators of the colonization and geographical expansion of this process.