The Cliff Swallow is found throughout California except n the southern deserts and at higher elevations.
The Cliff swallow spends the winter from around October through February in south America.
The Cliff Swallow eats flying insects. They can often be seen flyng only around under freeway overpasses and bridges. They are sensitive to cold snaps as many of the insects they eat die. They also drink water.
The Cliff Swallow is especially attracted to stucco buildings. These provide excellent surface areas for the nests to cling to. You also need a muddy area in your yard or near your home. For most people this is easy as their neighbors usually have a lawn that they over water. (If there is moss, than they are watering too much.)
The Cliff Swallow uses open areas especially near water where insects and mud are plentiful.
The Cliff Swallow builds a mud nest so they need a nest location close to a wet area where mud is available. Agricultural areas and riparian areas are usually nearby. They especially like freeway overpasses. These provide excellent nesting locations. The under the eaves of buildings are popular. Their nests need some protection from the elements as they are only made of mud and may dissolve under the full brunt of rain.