Alpine swifts are readily distinguished from the common swifts by their larger size and their white belly and throat. They are around twice as big as most other swifts in its range, about 20 to 23 cm (7.9 to 9.1 in) in length, with a wingspan of 57 cm (22 in) and a weight of around 100 g (3.5 oz). They're largely dark brown in colour, with white patches underneath the beak and on the breast that are separated by a dark brown streak. Juveniles are similar to adults, but their feathers are pale edged. In comparison, the common swift has a wingspan of around 42 cm (17 in). A dark neck band separates the white throat from the white belly. They have a short forked tail and very long swept-back wings that resemble a crescent or a boomerang but may (as in the image) be held stretched straight out. Their flight is slower and more powerful than that of their smaller relative.
Habitat and Distribution
Alpine swifts breed in mountains from southern Europe to the Himalaya. Like common swifts, they are strongly migratory, and winter much further south in southern Africa.
They never settle voluntarily on the ground, spending most of their lives in the air living on the insects they catch in their beaks. Alpine swift are able to stay aloft in the air for up to seven months at a time, even drinking water `on the wing`. Their vital physiological processes, including sleep, can be performed while in continuous flight.
These apodiformes build their nests in colonies in a suitable cliff hole or cave, laying 2?3 eggs. Swifts will return to the same sites year after year, rebuilding their nests when necessary, and pairing for life. Young swifts in the nest can drop their body temperature and become torpid if bad weather prevents their parents from catching insects nearby. They have adapted well to urban conditions, frequently nesting in old buildings in towns around the Mediterranean, where large, low-flying flocks are a familiar feature in summer.
Calls and Songs
They have a flight call that is a drawn-out twittering (listen at right)