Maybe there are some areas I don't see. Crows are not migratory birds, but resident birds. Crows are still common in winter in northern cities. Along Chang 'an Avenue in Beijing, Beijing Normal University is a gathering place for crows. In summer, most of them breed in mountainous areas.

In winter, crows gather in the city at night, and in the gradual gathering, crows gather in the center of the city for the winter. Due to the urban heat island effect, crows generally begin to shed their hair in September every year, and change into thick feathers in winter. In mid-June, they begin to gather in cities at 65438+ 10 to prepare for winter.

Crows gather in cities, mostly in winter when the temperature is low, or in the evening of spring and autumn. Because the temperature in cities is higher than that around them, crows prefer to spend the winter in warm places. Urban heat island effect means that the temperature of the city is higher than that of the surrounding areas because there is a lot of artificial heating in the city, and there are many buildings and relatively few greening in the city. Crows tend to stay in warm places when it is cold, so they often gather in cities when it is cold in winter.