An adult Brown Pelican in a relaxed pose. Pelicans are among the heaviest flying birds in the world.
■ The Brown Pelican nearly became extinct as a direct result of DDT poisoning. This chemical was widely sprayed in the 1950s and ’60s for insect control, and was the subject of the 1962 book Silent Spring. It accumulates in the body fat of animals, where it can persist for years. Insects each carry a tiny amount, but fish that feed on those insects are continually adding pesticide to their bodies, and when pelicans eat those fish they gradually add to their own pesticide load. This phenomenon—toxins becoming more concentrated higher up the food chain—is known as bioaccumulation. DDT interferes with the body’s use of calcium, and contaminated birds produce eggs with shells that break very easily. Pelicans were literally breaking their own eggs when they tried to incubate, leading to zero reproduction and a declining population. Fortunately, the trend reversed within a few years after the ban of DDT in the United States in 1972, and the Brown Pelican is once again a common sight along our southern coasts.
DDT (represented by orange dots) accumulating as it moves up the food chain from insects to fish to pelican
■ Kleptoparasitism is a fancy term for a strategy of stealing food. Some species of seabirds, especially gulls and their relatives, specialize in this behavior. When they see a bird that has captured a meal, they simply try to steal it for themselves. Laughing Gulls often hang around foraging pelicans, even standing on a pelican’s head, hoping to grab a few fish. The gulls are looking for fish that fall out as the pelican drains its pouch, but will also take any fish they can get out of the open pouch.
Brown Pelican and Laughing Gull