As we all know the African sun has a reputation for being extremely potent and the animals that live here in the Sabi Sabi Reserve have to somehow cope with this. Marabou Storks, as well as one or two other species, use a strategy called urohydrosis. This is, in very basic terms, the use of 'urine' for thermoregulation.
Marabou Storks are generally found a distance away from water and don't have the benefits of its cooling nature. They have dark legs that are inefficient at cooling the body, so what they do is 'urinate' on their legs. Technically speaking the birds do not actually urinate, they have a white excretion of uric acid out of the cloaca (the cavity used for excretion and reproduction).
In urohydrosis the 'urine' is diluted slightly and then excreted directly onto the legs. Once on the legs this liquid starts to evaporate and results in cooling. There is an additional advantage to the white powder left on the legs after evaporation has taken place; the white helps with further cooling by reflecting the harsh sun.
In human terms this is not the most attractive or hygienic way to cool yourself but it is obviously very effective and necessary in the life of these massive birds out here in the African bush.