Cranes are among Earth’s tallest birds that still fly
Fifteen crane species in four genera—Antigone, Balearica, Leucogeranus, and Grus—stalk wetlands on every continent but Antarctica and South America. Demoiselles stand about 90 cm; sarus cranes can reach 176 cm, while red-crowned cranes may weigh 12 kg.
Cranes are often called the tallest flying birds. They range from the demoiselle crane at 90 cm to the sarus crane at up to 176 cm, while the red-crowned crane is the heaviest, reaching 12 kg before migration. Unlike herons, they fly with neck stretched straight out. Species of wide open wetlands tend to be whiter and larger, while forest and small-marsh species are greyer and smaller; common and sandhill cranes even smear mud on their feathers, possibly as camouflage on the nest.
There are 15 species in four genera, rearranged after a 2010 genetic study showed the old genus Grus was not a natural group. They live on every continent except Antarctica and, oddly, South America. East Asia has the most, eight species, and Africa five residents plus a wintering sixth; the two crowned cranes of Africa are the only ones that roost in trees. In South Asia, sarus cranes breed in farm fields among dense human populations, helped by farmers’ goodwill.
Their windpipes coil into the breastbone, and in some species the two fuse, amplifying calls that carry for several kilometres. Pairs sing duets distinctive enough to identify individual couples. Bare red skin on the head swells to signal aggression.
Pairs hold territories while breeding, building platform nests in shallow water and usually laying two eggs; the young stay with both parents until the next season. Outside it, many species gather in big flocks. They eat everything from tubers and grain to snails, fish, and small mammals. Most species are threatened, and the plight of North America’s whooping crane helped spur some of the first US endangered-species laws.
Source: Crane (bird)
