Swift
- Swifts spend just three months of the year in Britain, arriving in early May and leaving in early August. This is a shorter period than any of our breeding birds other than the cuckoo.
- They spend their winters well south of the Sahara: British-ringed birds have been recovered in the Congo Basin, Malawi, Tanzania, Zimbabwe, Mozambique and South Africa.
- We still don’t know what routes the birds use to and from their wintering grounds.
- A young swift, ringed in Oxford on 31 July, was killed in Madrid on 3 August, having covered 1,300km in three days.
- Historically, swifts nested in holes high in large trees. They still do so in old Scots pines in Scotland’s Abernethy Forest.
- Today almost all swifts nest in colonies under the eaves of old buildings.
- They are long-lived birds, reflected in the fact that they lay just two or three eggs in a clutch, and only attempt to rear a single brood a year.
- Swifts are monogamous, and the same pairs will breed together in successive years.
- We find it impossible to tell the sexes apart, even when the bird is in the hand.
- No one knows whether pairs remain in contact with each other outside the breeding season.
- Swifts are creatures of the air: they roost on the wing, and are not thought to land between one breeding season and the next.
- Such an aerial lifestyle means that they even mate on the wing.
- Because they are totally dependent on airborne prey they are very susceptible to bad weather during the breeding season, when a lack of food often results in chicks starving to death.
- Young swifts can survive without food for up to 48 hours, lapsing into a semi-torpid state.
- The adult swifts migrate south within days of the chicks leaving the nest.
- Swifts feed at a higher elevation than both swallows and martins.
- They like to feed in the unstable air to the rear of a weather depression, where there is often a great abundance of insect life.
- Feeding birds will routinely fly great distances: British breeding birds have been found over Germany.
- Swifts have tiny feet and almost no legs, adaptations to their aerial lifestyle.
- Contrary to rumour, adult swifts can take off from a flat surface, though they rarely have to do so. Juveniles do have difficulties.
- The swifts’ closest genetic relations are the hummingbirds; they are not related to swallows or martins.
