Great cormorants gliding through a snowstorm in Hesse, Germany

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March of the cormorants. Great cormorants

Great cormorants are among the great anglers of the avian world. Found in Europe, Asia, Australia, Africa, and North America, they're expert at diving under the water's surface to catch bottom-dwelling fish. They sometimes even swallow pebbles to increase their weight, which enables deeper and longer dives. But these underwater fishing expeditions come at a price: Ironically for a water-diving bird, the great cormorant's plumage isn't sufficiently waterproof. As a result, cormorants must come ashore to dry themselves by spreading their wings open for long periods. This behaviour may also help with digestion or regulate their body temperature. Or maybe they're just showing off.