Strikingly ugly and bald, with a thick powerful bill, the Marabou stork is unforgettable. But what is that naked pink pouch that sometimes appears hanging under its bill?
This gular sac has two purposes: it helps keep the stork cool, as the skin has a dense concentration of blood vessels. It’s also a show-off device. In the breeding season, the male Marabou stork inflates the sac to impress rivals and prospective partners. The female will inflate hers in return. They also have a second air sac, small and normally hidden by feathers at the back of the neck, which swells like a red bubble during a display.Some possibly unrelated posts