The article considers cities as arenas of microevolutionary processes. The adaptation of “wild” bird species, and some mammals to cities and to their increase – urbanization is analyzed. The high rate of elementary evolutionary phenomena in all types of “man-made landscapes” is shown in comparison with the original biotopes.It is maximal in the development of cities. In this case, the population system of the species in the region is divided into two parts: dynamic populations and conservative ones. Dynamic populations 1) invade the landscape altered by humans, 2) change the biology and “structure” of the population system of the species towards greater lability of the basic relationships that underlie it – social, biotopic and territorial connections. These changes are universal in different bird species, including conservative ones and considered to be urbophobes. The development of urban areas by “wild” species is the quintessence of these processes, their urbanized populations are the most dynamic and most isolated from the original forest ones. Dynamic populations of the species are resistant to the continuation of anthropogenic landscape transformations and even benefit from them. They are opposed by conservative populations: passively holding onto the remaining “islands” of species biotopes, they are very vulnerable and doomed in the long term. Sooner or later, the transformation of habitats will surround and eliminate all their nesting sites. Therefore, urbanization and other forms of development of “man-made landscapes” associated with the formation of dynamic populations under the pressure of negative dynamics of biotopes at the level of the entire region are the last chance to save a variety of bird species in the old-developed regions of the planet.