If you find a swift on the ground it is likely to have a problem.
A healthy bird is quite capable of taking off from level ground. Swifts are complex birds and many factors could have caused the bird to ground.
Gently pick up the grounded swift and place in a suitable box on some warm fabric.
A professional swift carer should then be consulted before attempting to launch or treat the swift. A list of experienced rehabilitators is listed on the Swift Conservation website, who can advise and may be able to take care of the casualty.
Swifts carry many parasites, none of which can be transmitted to people. Most are harmless fleas and mites. One parasite, the louse-fly or flat-fly is found only on swifts. It does not affect humans but may alarm someone unprepared who picks up a swift.
Louse-flies are about 7 mm long with flattened triangular bodies and very small wings.