There is no other bird that can fly as well as the common swift. It even flies while sleeping. Common swifts make a high screeching sound and catch insects in flight. Although they have many resemblances to swallows, they are not related. In totally natural situations, they build their nests on rocks. However, due to a lack of rocky mountains in this country, they are contented with buildings, nesting mostly under the eaves. Therefore, it is no wonder that common swifts only breed in cities and villages with old buildings. Renovations and new buildings usually offer few nesting opportunities for common swifts.