Cranes are a family of large, long-legged and long-necked birds in the order Gruiformes. There are 15 different species of cranes, which are found on five continents. Cranes are among the planet’s oldest living birds and have existed for over 60 million years. They are revered in many cultures for their beauty, intelligence, longevity and complex social behaviors.
Cranes are omnivorous, feeding on a variety of plants, small vertebrates, invertebrates and occasionally fish. They have long, stick-like legs for wading through shallow water in search of food. Their long necks allow them to reach down to aquatic vegetation and fish. Cranes are monogamous breeders and produce some of the most elaborate courtship displays in the animal kingdom. Pairs often remain together for life.
Some key facts about cranes:
Physical Features
– Cranes range in size from the demoiselle crane, which measures 90 cm (35 in) tall, to the sarus crane, which can grow up to 176 cm (5 ft 9 in).
– They have long, straight bills and long legs with an elevated hind toe.
– Cranes have streamlined bodies and broad, rounded wings.
– Plumage is typically various shades of gray, with some species being white or black. Many have attractive red or black markings on the head.
– Cranes fly with their necks outstretched, unlike herons which retract their necks in flight.
Behavior
– Cranes are diurnal and fly to their feeding areas at dawn and return to roost at dusk.
– They soar high in V-shaped formations when migrating.
– Cranes are territorial and defend feeding areas in pairs or family groups.
– They have complex, ritualized social behaviors including elaborate dancing displays.
– Cranes frequently give loud, trumpeting calls to communicate within flocks.
– Pairs preen each other’s feathers and feed their chicks together as exemplary parents.
Habitat
– Cranes inhabit open wetlands including marshes, flooded fields, lakeshores and riverbanks.
– Some species prefer drier grasslands and agricultural areas.
– Northern species are migratory, breeding in the Arctic and subarctic, but wintering in wetlands further south.
– Southern species are non-migratory and reside year-round in the same regions.
Diet
– Cranes are omnivores, feeding on a wide variety of plant and animal matter.
– Their diet includes roots, tubers, berries, insects, earthworms, mollusks, reptiles, rodents and other small vertebrates.
– Wading cranes forage by probing their bills into mud or shallow water to catch prey.
– Some species will scavenge carrion and opportunistically feed on cultivated grains in agricultural fields.
Classification
Cranes comprise the family Gruidae, which contains 15 species divided among 4 genera:
Genus Grus
– Sandhill crane, Grus canadensis
– Siberian crane, Grus leucogeranus
– White-naped crane, Grus vipio
– Hooded crane, Grus monacha
– Black-necked crane, Grus nigricollis
– Red-crowned crane, Grus japonensis
– Demoiselle crane, Grus virgo
Genus Anthropoides
– Blue crane, Anthropoides paradiseus
– Wattled crane, Anthropoides virgo
Genus Balearica
– Grey crowned crane, Balearica regulorum
– Black crowned crane, Balearica pavonina
Genus Bugeranus
– Wattled crane, Bugeranus carunculatus
Major Crane Species
Here is more detailed information on some of the most remarkable crane species:
Sarus Crane
– Scientific name: Grus antigone
– The tallest flying bird in the world, standing up to 5 ft 9 in tall.
– Named “sarus” from the Sanskrit word meaning “crane”.
– Mostly found in northern India and southeast Asia.
– Grey plumage with a bare red head and upper neck.
– Often breeds and roams in pairs or small family groups.
– Omnivorous but mainly eats roots, tubers and insects including grasshoppers and crickets.
– Population under 10,000 and declining due to habitat loss. Classified as Vulnerable.
Sandhill Crane
– Scientific name: Grus canadensis
– The most abundant crane species with a global population over 500,000.
– Named for their sandy-colored plumage.
– Breeds across North America and Siberia. Winters in southern U.S. and Mexico.
– Standing 3-4 feet tall, they are the most common crane seen across North America.
– Forages on land for seeds, berries, tubers and small animals. Probe mud with bill for invertebrates.
– Form huge migratory flocks called “waves” that contain thousands of birds.
Demoiselle Crane
– Scientific name: Grus virgo
– The smallest species of crane, standing just 3 feet tall.
– Named for their delicate and maiden-like appearance.
– Breed in central Eurasia from the Black Sea to Mongolia. Winter in northern Africa and India.
– Plumage is silver-grey with black feathers on wings and head.
– Unlike most cranes, they prefer drier uplands over wetlands.
– Omnivorous, feeding on grains, buds, locusts and other insects.
– Populations remain robust with over 200,000 individuals.
Red-crowned Crane
– Scientific name: Grus japonensis
– Named for patch of red, bare skin on crown of head.
– One of the rarest crane species with a global population under 3,000.
– Breeds in eastern Russia and northeastern China. Winters in Japan and Korea.
– Stands 4-5 feet tall with white body, black legs and wing feathers.
– This endangered species depends on wetland habitats which are being drained and degraded.
– Omnivorous but mainly eats plant matter like roots, shoots, grains and berries.
– Aggressive and territorial especially during breeding season.
Australian Crane
– Scientific name: Grus rubicunda
– Also known as the Brolga crane. Endemic to Australia.
– Recognizable by the gray crown of curled feathers on its head.
– Often found in tropical grasslands and freshwater wetlands of northern and eastern Australia.
– Stands 4-5 feet tall with silvery-gray plumage and red coloring on legs and bill.
– Forages on aquatic plants, grains, tubers and some small vertebrates.
– Breeds April to June laying 1-2 eggs. Both parents incubate and guard the nest.
– Populations are stable with over 20,000 individuals. Listed as Least Concern.
Behavior and Biology
Cranes exhibit some of the most elaborate behaviors and social dynamics in the avian world. Here are some of their most notable qualities:
Intelligence
– Cranes have the largest brains relative to body size of any bird order.
– Their brain-to-body mass ratio exceeds that of chimpanzees and dolphins.
– Ancient Greeks considered cranes to be the ultimate symbol of vigilance, wisdom and intellect.
– Cranes display excellent memories, navigation abilities and adaptation to new problems.
Dance Displays
– Cranes perform elaborate ritualized dances to communicate with each other.
– Males and females bend, bow, leap and run while flashing their striking plumage.
– Dances play a role in courtship and pair bonding. Specific moves convey aggression, territory defense and greeting.
– Cranes will “dance” solo or synchronously in pairs or groups during breeding season.
Vocalizations
– Cranes have a distinctive trumpeting call that carries for miles.
– Males and females engage in loud duets to strengthen their pair bond and defend territory.
– Chicks peep softly when communicating with parents. Adults murmur quietly when incubating eggs.
– Cranes alter calls to signal alarm, aggression, greeting and other messages.
Migration
– Northern crane populations make annual migrations traveling thousands of miles between breeding and wintering grounds.
– Some species fly in huge flocks numbering hundreds or thousands of birds.
– Migrating cranes use thermals and updrafts to soar while conserving energy.
– Family groups migrate together, with older cranes likely passing on routes and stopover sites.
Longevity
– Cranes are exceptionally long-lived birds. Maximum lifespans in captivity approach 80 years.
– In the wild, they may live 20 to 40 years. The oldest known wild crane was 62 years old.
– Their longevity is aided by strong lifetime pair bonds where mates look after each other.
– Elderly crane pairs show higher reproductive success due to years of experience.
Parenting
– Crane pairs share parenting duties equally with both sexes incubating eggs.
– Parents carefully guard the nest and aggressively chase away potential predators.
– For the first 10-12 weeks, one adult remains with the chick at all times to protect it.
– Chicks develop slowly staying with their parents until they are nearly a year old.
Symbolism and Cultural Significance
Throughout history, cranes have been revered by human cultures which admired their intelligence, social bonds, longevity and majestic appearance.
Asia
– In China and Japan, the red-crowned crane is a symbol of luck, longevity, fidelity and moral purity.
– Origami paper cranes are popular amulets. Ancient Japanese believed folding 1,000 paper cranes granted a wish.
– Cranes were also associated with immortality in Chinese mythology. The Taoist Queen Mother of the West was said to have a crane as one of her incarnations.
Africa
– In many parts of Africa, crowned cranes are considered national symbols and frequently depicted on currency, stamps and emblems.
– Grey crowned cranes feature prominently in folk tales and proverbs of Nigeria and Uganda.
– The Kintu myth of the Buganda people credits the crane with guiding their first king to Uganda.
Native Americans
– Cranes were featured prominently in the mythology of Plains Indian tribes who mimicked crane dances.
– Lakota Sioux warriors called fallen crane feathers a sign of bravery.
– The Pawnee people believed departed souls turned into cranes and considered them a symbol of guidance.
Ancient Greeks
– According to Greek mythology, the boatman Charon transported souls to the underworld across the River Styx. The dead were instructed to offer him a crane on payment.
– Pythagoras used the crane’s behavior of standing on one leg with the other tucked under its body as a representation of a triangle.
– Ibycus, the famously wise ruler of Rhegium, used flying cranes as his mascot.
Threats and Conservation
Though several crane species remain abundant, others are endangered and at risk of extinction due to habitat degradation, climate change and other threats.
Habitat Loss
– The draining of wetlands for agriculture and human settlement destroys crucial crane nesting areas.
– Damming of rivers disrupts seasonal flood cycles that replenish feeding grounds.
– Increasingly arid climate in some regions reduces availability of freshwater habitats.
Collisions with Power Lines
– As tall birds with poor forward vision, cranes often fatally collide with power lines during flight.
– Utility companies can install line markers to increase visibility and prevent collisions near wetlands.
Hunting
– Cranes were historically hunted as game and for their feathers. While regulated in many areas today, illegal hunting persists in some regions.
Conservation Efforts
– Habitat restoration projects aim to rehabilitate degraded wetlands and create protected crane reserves.
– Captive breeding programs help supplement depleted wild populations for vulnerable species like the whooping crane.
– Public environmental education encourages communities to protect local crane populations.
– Strong policy protections classify most crane species as legally protected or prohibited from hunting.
Conclusion
Cranes hold a special place in human culture as symbols of nobility, good fortune and wisdom. These magnificent birds also play key ecological roles in wetland environments across the globe. While thriving in many regions, habitat loss poses severe threats to endangered species like the Siberian and whooping cranes. Protecting precious wetland ecosystems will be crucial to ensuring the future survival of these birds which have walked the Earth since the age of dinosaurs. Cranes remind us of the interconnectedness and fragility of life on our planet. Greater respect for the natural world will allow these iconic species to flourish for generations to come.