Common Swift

Common swifts are aerial feeders, predominantly feeding on a variety of flying insects and spiders lifted into the air by the wind. Their habitat is largely urban and suburban areas where they nest under eaves and in crevices of buildings but they originally nested in cliffs and hollow trees before human settlement expanded. They are highly adaptable and can be found in almost any terrain, excluding dense forests and deserts, as long as flying insects are abundant.

Swifts spend most of their life in the air, living on the insects they catch in flight; they eat, sleep, and even mate without ever needing to land. This continuous flight is facilitated by their incredible stamina and efficient flight mechanics, and they sleep by shutting down half their brain at a time. Swifts are rarely seen on the ground; their legs are so short and their wings so long that taking off from a flat surface is almost impossible for them. Therefore, they prefer to roost in elevated spots where they can launch into the air with ease.

Socially, common swifts are highly gregarious birds outside of the breeding season. They can often be seen flying in large, screaming flocks over rooftops and around buildings in urban areas, especially during the evening. This behavior is thought to be a way of communicating among individuals, possibly about feeding areas or as a pre-migratory gathering strategy.

Another interesting aspect of their behavior is their bathing technique, which involves flying low and skimming their bodies against the surface of a body of water. This not only cleans their feathers but also likely provides a cooling effect during hot weather. They also drink in a similar manner.

Known for their extraordinary migratory patterns, common swifts breed in Europe and migrate to sub-Saharan Africa to spend the winter. They are among the last birds to arrive in Europe in spring and early summer and among the first to leave, by late August to October, undertaking a journey of thousands of kilometers. A common swift can cover up to 200,000 km in a single year during its migratory movements, equating to nearly five trips around the Earth.

The breeding season for common swifts starts when they return to their breeding grounds in the spring. They are monogamous during the breeding season and both parents share responsibilities such as incubating the eggs and feeding the chicks. Nests are typically built in crevices in buildings, cliffs, or tree hollows. Females lay 2 to 3 eggs, which are incubated for about 18 to 19 days. The fledgling period lasts for about 6 to 8 weeks, during which the chicks are fed by both parents. Swifts have a strong fidelity to their nesting sites, often returning to the same spot year after year.

The common swift is currently listed as least concern on the IUCN Red List, thanks to its vast range and large population size. However, like many bird species, they face threats from habitat loss and changes in land use that reduce the availability of suitable nesting sites and feeding grounds. Conservation efforts focusing on preserving old buildings and providing nesting boxes can help mitigate some of these threats.