Walking home from work two swift flew over, dark arcs cutting through the air. This is the most aerial bird in the world. It can live in the air for months at a time, literally eating and sleeping in the air without landing. Whilst the Handbook of British Birds (Witherby et al) and the Birds of the Western Palearctic (BWP) go into considerable detail on the food of this bird, there is relatively little discussion of drinking habits. Both make reference to skimming the surface of sheets of water (so they don’t get all the fluid they need from their food), but is this the complete story? The skimming behaviour seems to me like a strategy which is only plausible in calm weather as the risk of ditching in choppy water seems too great. As an alternative consider this: can water be obtained from the air? An animal which is agile enough to live off flying insects caught on the wing and nothing else would seem to be capable of taking raindrops or water droplets from clouds. The challenge is now to go out and observe this.