Swifts will take shelter in their nests in heavy rain, even staying in for much of the day. I have watched them flying in front of and away from an approaching heavy thunderstorm. Local storms are regularly dodged in this way. Single swifts may fly up in this way to a number of nests in succession. This type of display is restricted to fine weather with little or no wind and is particularly noticeable on the first fine day after a spell of bad weather.
Swifts use the same nest year after year, merely adding fresh material.
This is caught in the air. As a result, building is erratic being most frequent when there is sufficient wind to sweep suitable material into the air. Dry grasses, straw, dead and green leaves, flower petals, winged seeds, feathers and scraps of paper have all been found in nests. Fresh poppy petals are sometimes used. The material is stuck to the nest with saliva.