Red-crowned Crane

The red-crowned crane (Grus japonensis), also called the Japanese crane and the Manchurian crane, is a large Northeast Asian crane among the rarest cranes in the world. In some parts of its range, it is known as a symbol of luck, longevity, and fidelity.

In the spring and summer, the migratory populations of the red-crowned crane breed in Siberia (far eastern Russia), Northeast China and occasionally in north-eastern Mongolia (i.e., Mongol Daguur Strictly Protected Area). The breeding range centers in Lake Khanka, on the border of China and Russia. Later, in the fall, they migrate in flocks to the Korean Peninsula and east-central China to spend the winter. Vagrants have also been recorded in Taiwan. In addition to the migratory populations, a resident population is found in eastern Hokkaidō, Japan. This species nests in wetlands, marshes and rivers. In the wintering range, their habitat consists mainly of paddy fields, grassy tidal flats, and mudflats. In the flats, the birds feed on aquatic invertebrates, and, in cold, snowy conditions, the birds switch to mainly living on rice gleanings from the paddy fields. The cranes once lived on Japan's main island of Honshu, but a permanent population no longer survives there.

Japan

Red-crowned cranes have a highly omnivorous diet, though the dietary preferences have not been fully studied. They eat rice, parsley, carrots, corn, redbuds, heath berries, acorns, buckwheat, grasses and a variety of water plants such as reeds. The animal matter in their diet consists of fish, including carp and goldfish, amphibians, especially salamanders, snails, crabs, dragonflies, other insects, small reptiles, shrimp, small birds and rodents. The daily food requirement of adult red-crowned cranes is 750 g (26 oz). They seem to prefer a carnivorous diet, although rice is now essential to survival for wintering birds in Japan and grass seeds are another important food source. While all cranes are omnivorous, per Johnsgard, the two most common crane species today (the sandhill and common cranes) are among the most herbivorous species while the two rarest species (the red-crowned and whooping cranes) are perhaps the most carnivorous species. When feeding on plants, red-crowned cranes exhibit a preference for plants with a high content of crude protein and low content of crude fiber. In Hokkaido, fish such as Tribolodon, Pungitius, Sculpin and flatfish was major prey of adults, while chicks mostly feed on various insects. In Zhalong Nature Reserve, small fish less than 10 cm (3.9 in), such as common carps, pond loach, and Chinese sleeper was mainly taken as well as aquatic invertebreas like pond snails, dragonflies, water beetles and large amount of plant matter. Elsewhere, mudflat crabs are locally important food source in Yellow River Delta. They typically forage by keeping their heads close to the ground, jabbing their beaks into mud when they encounter something edible. When capturing fish or other slippery prey, they strike rapidly by extending their necks outward, a feeding style similar to that of the heron. Although animal prey can be swallowed whole, red-crowned cranes more often tear up large prey by grasping with their beaks and shaking it vigorously, eating pieces as they fall apart. Most foraging occurs in wet grasslands, cultivated fields, shallow rivers, or on the shores of lakes.

Flock sizes are affected by the small numbers of the red-crowned crane, and given their largely carnivorous diet, some feeding dispersal is needed in natural conditions. Wintering cranes have been observed foraging, variously, in family groups, pairs, and singly, although all roosting is in larger groups (up to 80 individuals) with unrelated cranes. By the early spring, pairs begin to spend more time together, with nonbreeding birds and juveniles dispersing separately. Even while not nesting, red-crowned cranes tend to be aggressive towards conspecifics and maintain a minimum distance of 2 to 3 m (6.6 to 9.8 ft) to keep out of pecking range of other cranes while roosting nocturnally during winter. In circumstances where a crane violates these boundaries, it may be violently attacked.

The red-crowned crane is monogamous and long-lived, with stable pair-bonding both within and between years, and believed to mate for life. The breeding maturity is thought to be reached at 3–4 years of age. All mating and egg-laying are largely restricted to April and early May. A red-crowned crane pair duets in various situations, helping to establish the formation and maintenance of the pair bond, as well as territorial advertisement and agonistic signaling. Both males and females may start a duet with the production of a start call, but the main part of the duet always began with a long male call. The pair moves rhythmically until they are standing close, throwing their heads back and letting out a fluting call in unison, often triggering other pairs to start duetting, as well. As it occurs year-round, the social implications of dancing are complex in meaning. However, dancing behavior is generally thought to show excitement in the species. Also, the performance of duet displays increased the probability of staying in a favorable area, supporting the hypothesis that duet displays function as a signal of joint resource defense in the flock. Pairs are territorial during the breeding season. Nesting territories range from 1 to 7 km2 (0.39 to 2.70 mi2) and are often the same year after year. Most nesting territories are characterized by flat terrain, access to wetland habitat, and tall grasses. Nest sites are selected by females, but built by both sexes and are frequently in a small clearing made by the cranes, either on wet ground or shallow water over waters no more than 20 to 50 cm (7.9 to 19.7 in) deep. Sometimes, nests are built on the frozen surface of water, as frigid temperatures may persist well into nesting season. Nest building takes about a week. A majority of nests contains two eggs, though one to three have been recorded. Both sexes incubate the eggs for at least 30 days. They also both feed the young when they hatch. Staying in the nest for the first few weeks, the young start to follow their parents as they forage in marshes by around 3 months of age. New hatchlings weigh about 150 g (5.3 oz) and are covered in yellow natal down for two weeks. By early fall, about 95 days after hatching, the young are fledged and are assured fliers by migration time. Although they can fly well, crane young remain together with their parents for around 9 months. Young cranes maintain a higher-pitched voice that may serve to distinguish them from outwardly similar mature birds, this stage lasting until the leave parental care. The longevity of these birds is largely unknown, but assumed to live 20 to 30 years in wild. The oldest wild individual in Hokkaido died at the age of 35. In captivity, these bird may live up to 65 years. The oldest captive individual ever Recorded, named mali, died at the age of 46 in the Kushiro Zoo. Another individual, named 'Momo', is currently living at Tama Zoological Park at the age of 45.

Adult red-crowned cranes are named for a patch of red bare skin on the crown, which becomes brighter during the mating season. Overall, they are snow white in color with black on the wing secondaries, which can appear almost like a black tail when the birds are standing, but the real tail feathers are actually white. Males are black on the cheeks, throat, and neck, while females are pearly gray in these spots. The bill is olive green to a greenish horn, the legs are slate to grayish black, and the iris is dark brown. Juveniles are a combination of white, partly tawny, cinnamon brown, and rusty or grayish. The neck collar is grayish to coffee brown, the secondaries are dull black and brown, and the crown and forehead are covered with gray and tawny feathers. The primaries are white, tipped with black, as are the upper primary coverts. The legs and bill are similar to those of adults but lighter in color. This species is among the largest and heaviest cranes, typically measuring about 150 to 158 cm (4 ft 11 in to 5 ft 2 in) tall and 101.2–150 cm (3 ft 4 in – 4 ft 11 in) in length (from bill to tail tip). Across the large wingspan, the red-crowned crane measures 220–250 cm (7 ft 3 in – 8 ft 2 in). Typical body weight can range from 4.8 to 10.5 kg (11 to 23 lb), with males being slightly larger and heavier than females and weight ranging higher just prior to migration. On average, it is the heaviest crane species, although both the sarus and wattled crane can grow taller and exceed this species in linear measurements. On average, adult males from Hokkaidō weighed around 8.2 kg (18 lb) and adult females there averaged around 7.3 kg (16 lb), while a Russian study found males averaged 10 kg (22 lb) and females averaged 8.6 kg (19 lb); in some cases, females could outweigh their mates despite the males' slightly larger average body weight. Another study found the average weight of the species to be 8.9 kg (20 lb). The maximum known weight of the red-crowned crane is 15 kg (33 lb 1 oz). Among standard measurements, the wing chord measures 50.2–74 cm (19.8–29.1 in), the exposed culmen measures 13.5–17.7 cm (5.3–7.0 in), tail length is 21.5–30 cm (8.5–11.8 in), and the tarsus measures 23.7–31.9 cm (9.3–12.6 in).

In the 19th century, the red-crowned crane was revered as the god of the wetland | 湿原の神 (サロルンカムイ, Sarurun Kamuy) by the Ainu people of Hokkaido. As a large wading bird occupying a high position in the wetland food chain, it served as a keystone species for wetland biodiversity. In the 1960s, human activities in Northeast China and the Far East led to habitat destruction for red-crowned cranes. Reclamation projects not only seized original habitats but also severed interconnected waterways. Compounding this, the Far East has experienced a pronounced trend toward aridification in recent years, causing severe reductions in wetland areas. Pollution introduced by human activities further threatened the cranes' survival. Moreover, land-clearing practices like slash-and-burn farming severely damaged nesting materials and cover, narrowing their distribution range. During the 1980s, economic development in East Asia created a specific demand for crane feathers and livers, making hunting inevitable. Although direct hunting has become rare in recent years due to conservation regulations, poisoning used to hunt other waterfowl has become a major cause of death for red-crowned cranes. Currently, the red-crowned crane is a Class I protected animal in China listed as Endangered in the IUCN Red List, and included in Appendix I of the Convention on International Trade in Endangered Species of Wild Fauna and Flore (CITES). By the end of 1999, China had established 33 nature reserves primarily dedicated to protecting the red-crowned crane and its habitats, covering a total area of approximately 3,099,000 hectares. Key reserves include the Three Rivers, Xingkai Lake, Zhalong, Momoge, Xianghai, Horqin, Shuangtai River Estuary, Yellow River Delta, Beidaihe, and Yancheng nature reserves. Japan designated the red-crowned crane and its breeding grounds as Natural Monuments in 1935. In 1952, the Kushiro Red-Crowned Cranes were designated as Special Natural Monuments. By 1967, red-crowned cranes across all regions of Japan were designated as Special Natural Monuments. In 1993, the species was further designated as a Rare Wild Animal and Plant Species.

The red-crowned crane is endemic to Northeast Asia, yet holds a prominent position throughout East Asian art history. In East Asia culture, the red-crowned crane carries the cultural significance of an "auspicious bird". The phoenix is considered the foremost auspicious bird, followed by the red-crowned crane and other birds, Depictions of the red-crowned crane as a bird imbued with Taoist ethereal qualities can be found in numerous Chinese and Japanese paintings, poetry crafts, and literature.