These are no doubt unmistakable, they are the only white pelicans in North America.  Pelicans have a vertebra in their neck, which prohibits them from ever raising their face.  The white pelican is 60 in. in length and 107 in. in width, one of the largest of the 8 true species of pelicans.  They have a yellowish pouch connected to the lower mandible of the beak that stretches up to six inches.  Their bodies are mostly white, with black primaries and outer secondaries, which are hidden until the bird outstretches it's enormous wings.  During mating season the male develops a fibrous plate on the upper part of the beak, this is a unique characteristic of the white pelican.  Also the bill is bright orange during the mating season.  Their feet are orange, and are webbed not only between the four front toes but also between the second toe and the inwardly directed back toe.  They have an enormous wingspan of 8 - 9.5 feet.  Their legs are orange, and are extremely short.
 

These pelicans are very fond of company, and they usually stay together in large colonies to bring up their families.   Most of the time they can be seen together in groups on feeding trips.  These pelicans are found near lakes, salt bays, marshes, and beaches.  The bird is found in such states as northern California, western Nevada, Utah, Colorado, northeastern South Dakota, southwestern Minnesota, and occasionally on the central coast of Texas.  During winters the pelican is found  along the Pacific coast from central California and southern Arizona south along the western lowlands of Mexico to Guatemala and Nicaragua and from Florida and the Gulf states south along the Gulf coast of Mexico to Tabasco and the state of Yucatan.  The White Pelican's nest is usually constructed out of sticks, grasses, and reeds built of the ground.  Usually an island or an inland lake is chosen.  Two to four chalky white eggs are produced, and the incubation period is 1 month.  Both parents help in feeding the young, they do this by regurgitating food and the young stick their heads into the parents beak to feed.  Adults rarely make any noise, but when they do it is usually a low grunt.  However, the young feel the need to squeal, and are very noisy.

Pelicans are naturally very large in size, but in spite of this they can sit high on the water because their bones are full of air and the air sacs in their body are large.  Also as a benefit, their large beak and stretchable skin underneath make it easier for them to catch food.  The American White Pelican is different from other pelicans, in that it does not drop from great heights to catch its prey, it simply floats along the water and scoops up fish with it's enormous bill.  The bill can hold 3 gallons of water, and after the fish have been caught the bill is pointed downward allowing the water to drain, and then the bill is raised and the bird swallows.

      Comments about the American white pelican of the Fort Worth Zoo. 

There are 8 true species of pelicans.  Many of them are very closely related.  
The Pelican is in the Kingdom Animalia, the Phylum Chordata, the Subphylum Vertebrata, the Class Aves, the Order Pelecaniformes, the Family Pelecanidae, the Genus Pelecanus, and the American White Pelican is in the Species Pelecanus erythrorhynchos.  All of the pelicans make their nests on low bushes or on the ground, except for the spotted billed pelican of Asia which nests in trees.  The pelican of Europe is closely related to the American bird, which it resembles in habits and in plumage. 

There are three American White Pelicans at the Fort Worth Zoo.  I noticed that for the most part they stayed very near one another.  They continuously  stretched their pouch out over their chest, perhaps cleaning it.  When one pelican wanted its own space, it opened up its wings which are 8 - 9.5 feet wide when opened.  They didn't seem to care where they went to the bathroom, but then I wouldn't expect that from them.  Unfortunately I didn't get to see them eat.