Common Swift (Apus apus)
This migratory bird is one of the last birds that arrive to Slovakia for breeding. It appears usually at the end of April / beginning of May and stay here till the beginning of August when it leaves back to winter sites in Africa. Its typical birdcall is a symbol of summer time in our region. Swifts are characteristic with notably long sickle-shaped wings and forked-shaped tail that allow them a fast flight and excellent manoeuvring. Swifts are dark-brown with a pale patch on the throat. Young birds have whitish edge of the feathers and the pale patch on the throat is larger. Swifts have short and wide beak, which shape and size are well adapted to catching small insects and invertebrates in the air. Swifts can live 10-15 years.
Swifts often tend to escape from the forthcoming rain, that´s why they are called „dážďovník“ (dážď means rain). In comparison Czech name - rorýs - suits them much better, because it sounds as their call. The scientific name Apus apus (based on Greek a-poda – without legs) points to their short legs. Swifts use them really very rarely - only for clinging to vertical surfaces. Their movement on the horizontal surfaces looks rather like crawling then walking. They have four fingers and all of them are front. This adaptation allows them to persist on a vertical surface close to the nest. To start flying the swift needs to “jump” into a free-fall, usually a few meters. Swifts very rarely sit on the ground. If this happens the birds generally need our help to get back in the air again.
Swifts often spend the whole night up in the air. They can fly and sleep in the same time. There were observed a few cases of sleeping swifts hanging on leafs and branches of trees. These birds are not able to sit on horizontal surfaces (comparing to e.g. swallow sitting on wires) and they are also hanging on vertical surfaces very rarely. In a bad weather it is possible to see them hanging on the walls, sporadically also on window´s ledges.
Swifts are social birds, often flying in serried flocks. During wintering in Africa they form mixed flocks with another species of swifts. To an unexperienced eye the swift flocks may look like flocks of other birds, e.g. Barn Swallow, House Martin or Sand Martin. However, in intensively urbanized areas only flocks of House Martin and Common Swift can be usually observed. House Martin is smaller, its wings are much wider and shorter and abdominal part is completely white.
The swifts’ call is a typical loud „srííí“. In our cities Swifts are nesting mostly in buildings, in any holes and gaps. In panel houses they occupy mainly ventilation holes in attics and crevices between panels. They are creating urban populations of birds in an environment where there are not many other species living. Swifts are bound to their nests and usually return to the same nesting place for many years. The proper nest is a small basin often in a ventilation hole or crevices between panels filled with feathers, grass or leaves. They catch the nesting material in the air. Swifts defend their nests one from another and attack unexpected visitors of the nesting sites in the air.
Similar bird species: Barn Swallow (Hirundo rustica), House Martin (Delichon urbica), Sand martin (Riparia riparia)