Once part of the urban horizon, crows are leaving Iranian cities.

Since the 1980s scholars have studied the influences of urbanization on the environment, particularly the ecosystem. The rapid growth of the urban population and especially the lifestyle of the urban dwellers have undeniable effects on the life of living species and plants. Birds are of the animals that are completely affected by urbanization. Among several studies that have been done on the effects of the urban life on ecosystem, some are on the influences on the life of urban birds. Such studies show how urbanization modifies the life of avian communities of the cities by influencing food, water, climate, and predators.

During the past years, the lives of urban birds of the Iranian cities have been monitored by activists. This was started when reports of fleeing birds of Tehran were given out. While many believe that the birds of Tehran are really less than before, some say that the birds just move from the regions with higher pollution to the less-polluted parts. So the population of birds in some regions is even more than before.