In contrast, the barn swallow is distinguished by its long, deeply-forked tail. Distribution and Habitat Cliff swallows are found throughout California, except in high mountains and the dry southeastern desert. The original nesting sites of cliff swallows were cliffs and walls of canyons. Structures, such as buildings, bridges, and overpasses, and agricultural activities have increased the number and distribution of suitable nesting sites, and cliff swallow populations have increased accordingly. In general, wherever irrigation water and buildings or other structures are found, suitable breeding conditions may exist.
Cliff swallows spend the winter months in South America.
In late winter and early spring, they begin a northward migration over land through Central America and Mexico. Arrival dates can vary greatly because of weather conditions. Usually by late February or early March, the first migrants appear in southern California. Two or three weeks later, cliff swallows begin arriving in northern California. Cliff swallows migrate during the day and catch flying insects enroute.