A pelican's beak pouch can hold about 13 litres of water - more than three big bottles of fizzy drink. When the pelican dips its head into the water, it scoops up fish and water together. Then it tips its head forward to let the water drain out, and swallows the fish on its own.
Pelicans often fish together as a team. They paddle in a long line or a U-shape and beat their wings on the water, herding fish into shallow water. Then everyone scoops at once. It's a kind of underwater sheep-dog routine, done with beaks.
Even though they are heavy birds (8-15 kg - heavier than a baby), pelicans are brilliant fliers. They use rising hot air to soar without flapping, the way condors and eagles do. A flock of pelicans in the sky looks like a slow, white spiral.
Djoudj, where so many pelicans gather, is the third-most-important bird sanctuary in the world. Around 3 million birds visit it each year - pelicans, flamingos, herons, ducks and many more - mostly during the European winter, when they fly south to find warmer water and lots of fish.