Amazing facts about the swift…
Their scientific name is Apus apus meaning ‘no foot no foot’. They have small, sharp claws adapted to their aerial life, designed to help them climb into their nest sites. If they land on the ground, it’s very difficult for them to get airborne again.
Click here to find out what to do if you find a grounded swift.
Closest relative
The swifts’ closest relation is in fact the hummingbird. They are not related to swallows or house martins and unlike those birds, swifts cannot perch on wires or branches.
Their journey
Swifts arrive in the UK in late April/early May, staying only until mid-August. Other than the cuckoo, no other breeding bird spends so little time on our shores. They need warm weather as insects are their only food source, so their winter months are spent south of the Sahara. The route they take to and from their wintering grounds is still a bit of a mystery and is much influenced by weather systems. Ringed birds from the UK have been found around the Congo Basin, Tanzania and South Africa. From geo-tracking, birds have been seen to travel 14,000 miles per year - that’s a lot of airmiles!
Life on the wing
Swifts are creatures of the air, only landing to breed. They eat, drink, preen, sleep and mate on the wing. They’ve been known to travel hundreds of miles a day to find food, with British birds having been found over Germany. They are essentially an African bird.
Swifts only start breeding when they’re 2-3 years old. Until older enough to breed, they make the same journey to the UK as the adults, arriving a few weeks later in what is referred to as the ‘second wave’, sometime in early June. These young birds are often called ‘The ‘Bangers’ because they literally hit the walls of buildings prospecting for new nest sites.
Swifts feed exclusively on flying insects such as midges, mosquitoes, aphids and flies and also on airborne spiderlings. When feeding their young they can store as many as 1000 insects in their throat pouches before returning to the nest.
Family life
Swifts are monogamous, staying with the same partner over successive years - and they are long-lived birds, some reaching 21 years of age. They lay just 2-3 eggs, generally attempting to raise just one brood a year. Traditionally nesting in large, old trees, they now favour the eaves and gables of buildings where they nest in colonies. Both partners take turns in incubating the eggs and feeding the young.
Swift chicks
Young swifts, called swiftlets are born blind with no feathers. Their eyes open after just 6 days and they are fed many times a day by the parents who bring them a ‘bolus’ (or ball) of around 300-500 insects. Chicks have white throats; it seems this is to help the parents see them in the dark. How fascinating!
Young swifts can survive without food for up to 48 hours, going into a semi-torpid state to survive. A useful adaptation, particularly in bad weather when parents may struggle to provide sufficient insects.
Preparation for travel is key. Swiftlets do wing push-ups to build up strength in their wings and tail – they also stop eating a few days before they leave to lose weight (they can’t fly if they’re too heavy!).
Once the chicks leave the nest, they head straight for Africa, travelling hundreds of miles in one go and remaining airborne for up to 2-3 years before they themselves are ready to partner up and have a family of their own.
With their young swifts departed, it’s not uncommon for the parents to hang around for a few days longer, using the nest site to roost, before they too embark on the same journey south.