1) Apply some drops of water round its beak with your finger. Do not try to feed the bird or make it drink if it is shocked.
2) Shock, injuries or wounds? See a veterinarian immediately who is knowledgeable about birds. Instant shock treatment has first priority, every hour counts! Do not throw the bird into the air. Do not set it free, before it has been examined carefully. For transport: use a lined cardboard box. No bird-cage!
3) Weigh the bird to verify its general condition. Rough rule of thumb: a feathered Common Swift weighing less than 30g: extremely critical! Instant treatment by a vet is necessary.
4) For transport: Carry the bird in a plastic or cardboard box lined with Kleenex or a soft towel, never in a bird-cage. Keep injured, undercooled or emaciated birds warm. (for instance use a thermo-lamp, 32-35°; no UV light). Provide for dim light and quiet.
5) Procure food! Fist choice: crickets (subadult, without wings) available in most pet-shops. If not available:
a) Employ family and friends. Let them catch flies, mosquitos, grasshoppers and spiders (no earthworms).
b) Try to get dark (almost mature) drones from local bee-keepers. (sometimes your local fire-fighters know where to find bee-keepers).
In the beginning, feed small portions only and make sure that the bird swallows properly and has bowel movement. Make sure that the bird does not swallow up. The entrance to the wind-pipe is right behind the tongue.
Feed with clean, blunt tweezers. Putting one`s finger into the bleak without thorough cleaning and disinfecting could cause infections.