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.

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).

The scientific name Grus japonensis matches the English common name Japanese crane, though its primary habitat is in mainland Northeastern Asia. The common name red-crowned crane is a direct translation of the Chinese names dāndǐng hè (丹頂鶴) and hóngguān hè (紅冠鶴) and the Japanese tanchō (丹頂) and tanchōzuru (丹頂鶴). Manchurian crane is used in older sources and refers to the center of the crane's habitat in Manchuria. In Korean, the bird is referred to by its native Korean name durumi (두루미) as well as the Sino-Korean hak (학; 鶴, lit. "crane").

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.^{[citation needed]}

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.