Editing Common swift (section)

===Migration===
Subjects of a geolocator tracking study demonstrated that swifts breeding in Sweden winter in the Congo region of Africa.<ref name=Akesson2012/> Swifts spend three to three-and-a-half months in Africa and a similar time breeding – the rest is spent on the wing, flying home or away. Unsuccessful breeders, [[fledge|fledglings]], and sexually immature year-old birds are the first to leave their breeding area. Breeding males follow next, and finally the breeding females. The breeding females stay longer in the nest to rebuild their fat reserves. The time of departure is often determined by the light cycle, and begins at the first day of less than 17 hours light. For this reason, birds further north, for instance in Finland, leave later in the second half of August. These latecomers are rushed through the quickly shortening days in Central Europe and are barely seen by bird watchers.

The prevailing direction of travel through Central Europe is south-by-southwest, and so the Alps do not present a barrier. In bad weather, the swifts follow rivers, because they can find a better food supply there. The population of Western and Central Europe traverses the Iberian peninsula and northwestern Africa. Swifts from Russia and southeastern Europe make a long journey over the eastern part of the Mediterranean. It is unclear where the two groups meet. The western group of swifts mostly follow the Atlantic coastline of Africa – otherwise they would have to cross the Sahara. Once they arrive at the humid savanna, they turn southeast to arrive at their winter feeding grounds. During the summer in Africa, there is a great bounty of insects for the swifts, since the region lies in the [[Intertropical Convergence Zone]]. The swifts have a nearly unbroken presence in the sky.{{explain|date=February 2024}}

A few swifts, usually some of the sexually immature one year olds, remain in Africa. The majority fly northwards through Africa, then turn east towards their destinations. The birds use low pressure fronts during their spring migrations to exploit the southwestern flow of warm air, and on the return trip, ride northeastern winds on the back of the low pressure fronts.

In Central Europe, the swifts return in the second half of April and the first third of May, and like to stay in lowlands and near water rather than in high places. In more northerly regions, the swifts arrive later. The weather along the journey has an enormous influence on the arrival date, so in one region the swifts may come back at varying times year to year.