Great White Pelican - Pelecanus onocrotalus
The Great White Pelican is among the largest of the pelicans; while Dalmatian Pelicans (Pelicanus crispus) often weigh more than Great Whites, the wingspan of a Great White can reach up to 11.8 ft (360 cm) in length, rivaling only the great albatrosses.
As you can see here, Great “White” pelicans aren’t always white - another name for them is Rosy pelicans, and for good reason. The habitat of Great Whites spans from the Mediterranean to Tibet, from East Africa to the Indian deltas, and across its vast territory, its diet varies considerably. In Africa and Eurasia, their diet consists mainly of small-to-midsized fish, such as mullet and carp.
However, among parts of the Mediterranean and South-East Asia, the predominant food source is small crustaceans, such as shrimp, and that food is very high in substances known as carotenoids. These organic pigments break down into alpha-carotene and beta-carotene, which provide essential vitamins, but when there is excess pigment ingested, the unprocessed remainder is pushed into the feathers, giving “White” pelicans a decidedly pink hue. This is the same process that goes on in flamingos - when their diet is rich in carotenoids, they are a flush and vibrant pink, and when it’s not, they’re a much lighter pink, or even close to white.
Wild Life of the World, Vol I. Richard Lydekker, 1916.