The brown pelican [Pelecanus occidentalis] is found throughout the islands, skimming over the water, plunge-diving, and resting in mangrove trees. In addition to Galapagos, the brown pelican is found along the western coasts of northen South America, Central America, and North America, and throughout the Caribbean. The Galapagos population of brown pelican is considered to be an endemic subspecies.
Adult pelicans can be distinguished from juveniles by their plumage. Juveniles tend to have gray face, skin, bill, and legs, with a brown body. Adults have a white neck, gray-brown upper body and brown to black lower body. The neck is white, often with a yellowish crown. In breeding season, the back of the neck is a rich chestnut brown. The individual in the picture above is an adult in non-breeding plumage.
They build their nests in mangroves or in low-lying coastal bushes such as salt bush [Cryptocarpus]. Female pelicans lay two to three eggs and both parents share in incubation and feeding. Of all the pelecaniformes, the pelican has the largest gular sac, from which the juveniles feed. Pelicans breed throughout the year, but individual colonies tend to breed synchronously. The best place to see breeding pelicans is Isla Rabida.
The pelican hits the water with open mouth and it seems to flatten on the surface, with its tail and feet never penetrating. Underwater, the pelican traps fish, along with several gallons of water in its gular sac. It will sit for a moment, with it's head under, trying to remove the water, all the while retaining the fish. Not surprisingly, it sometimes loses some or all of its catch. I have often seen mixed flocks of pelicans, blue-footed boobies, and brown noddies fishing. When the pelicans dive, the noddies swarm them, sometimes perching on the the pelicans' heads, hoping to pick p a free meal. I have never seen them mob the boobies in a similar manner. Nevertheless, this style of fishing seems to be difficult to learn. Pelicans tend to be successful at raising their chicks, but many juveniles, once on their own, die of starvation because they cannot master the technique.