Urohidrosis

Back in the 1960s, while observing wood storks in Florida, biologist M. Philip Kahl, Jr. noted that on hot days the storks "have the unusual habit of frequently excreting on their legs."

He eventually concluded that, since storks don't sweat, they were doing this to cool themselves down "by means of evaporative cooling of the blood supply to the legs and feet." He named this phenomenon 'urohidrosis'.

His hypothesis is now accepted as true, and it's not only storks that cool themselves by pooping on their legs. Turkey vultures do it too.

Reference: Kahl, P.M., Jr. 1963. Thermoregulation in the Wood Stork, with special reference to the role of the legs. Physiol. Zool., 36: 141-151.