|Clouds of Red-billed Quelea drinking in Tarangire NP, May 2011|
As they come in to drink you'll see them dipping their beak into the water, tipping their head back and letting the water flow back to their crops then repeating the process. Most birds drink like this - they can't suck as we can, so have to 'sip and tip' to do so. But there are some exceptions, one of which is pretty sure to turn up at every waterhole within a few moments of you: Doves (also sandgrouse, which we believe to be closely related to doves, and a few parrots).
|Not drinking (sorry) but an Emerald-spotted Wood Dove in Kruger NP, May 2011|
And, of course, if you should happen to see a sandgrouse come in you'll see the same drinking, but you might also see the males (only males apparently) filling their specially adapted breast-feathers to take water back for the chicks. Their dry, seed-filled diet means all sandgrouse have to drink daily, and estimates suggest that in the driest times of the year adults may fly a round trip of up to 160km from the nest to waterholes in some species. Even though they are very fast fliers - they can easily do 70kph - that's still a long trip! (Sandgrouse facts from here, but you probably won't have free access.)