White-Naped Crane
It is a large bird, 112–125cm long, approximately 130cm tall and weighing about 5.6kg with pinkish legs, grey and white striped neck, and a red face patch. The White-naped Crane is a symbol of peace for the people of the Korean peninsula. Adults are dark grey and have a white striped neck, reddish face patch, body plumage is dark grey, wings are silvery grey, pinkish legs. Juveniles body plumage is a mix of grey and cinnamon-brown, their striping on the neck is not as distinct as the adults. At 125cm and weighing 5.6kg, this species is almost as large as the red-crowned crane. The tracheas of this and other crane species are very long and pierce their sternum, enabling the birds' loud vocalizations or bugling. The nape is the back of the neck, this species’ name coming partly from this part of the body.
Habitat
These cranes breed in northeastern China, northeastern Mongolia, and adjacent parts of southeastern Russia. Individuals in the western part of the breeding range will migrate south through China, stopping to rest at the Yellow River delta, then wintering in wetlands of the middle Yangtze River valley. Overwintering areas include the Demilitarized Zone that separates North and South Korea, as well as the Japanese island Kyushu, where there is an artificial feeding station outside the city of Izumi which they heavily rely upon. These birds prefer shallow wetlands or wet meadows within broad river valleys, near lake edges, and within lowland steppes or areas that are mixed forest-steppe. They feed nest, and roost in shallow wetlands and along the edges of wetlands, foraging in the adjacent grasslands or farmlands. While migrating and at their wintering grounds, they will use rice paddies, agricultural fields, mudflats, and other wetlands.
Diet
This species is omnivorous. They are proficient diggers, excavating the tubers of several species of sedges and feeding on plant matter, such as seeds, roots and tubers of aquatic plants. They also eat insects and small vertebrates, such as amphibians and rodents. Outside of the breeding season, white-naped cranes consume more grains, seeds and tubers.
Breeding
They engage in unison calling, which is a complex and extended series of coordinated calls. The birds stand in a specific posture, usually with their heads thrown back and beaks skyward, during the display. Females initiate the display and utter two calls for each male call. The male always lifts his wings over his back during the unison call, while the female keeps her wings folded at her sides. All cranes engage in dancing, which includes various behaviors such as bowing, jumping, running, stick or grass tossing, and wing flapping. Dancing can occur at any age and is commonly associated with courtship. However, it is generally believed to be a normal part of motor development for cranes and can serve to thwart aggression, relieve tension and strengthen pair bonds.
The white-naped crane's breeding season is in the spring from April to June. Nests are mounds of dried sedges and grasses in open wetlands. Females usually lay two eggs at two or three days apart and incubation(by both sexes) lasts 28 to 32 days. Both parent birds take part in building the nest, incubating the eggs and rearing the chicks. The male takes the primary role in defending the nest against possible danger. White-naped crane chicks are yellow-brown with some darker spots. They are fed by both parents and fledge about 70 to 75 days after hatching. Young birds are sexually mature at 2 to 3 years of age.
Population
The total population is estimated at 6250-6750 individuals, based on recent counts of 500-1,000 individuals wintering in China, and an estimate of 5,750 wintering in Korea/Japan (based on coordinated counts from winters 2012-2013, 2013-2014 and 2014-2015. Double counting is possible between the Korean sites and Japanese sites due to movement of birds during the wintering period, and counts therefore require close coordination.
Although accurate data on population trends are lacking, numbers are thought likely to be in rapid decline owing to habitat loss in both the breeding and wintering grounds, as well as other confounding factors such as hunting, disturbance, nest predation and pollution.
Threats
The loss of wetlands to agricultural expansion and growing human demand for water, on both breeding and wintering grounds, is the main threat. The drought is part of a climatic cycle, and is predicted to persist until 2015. Breeding birds are also threatened by steppe fires, whilst livestock grazing may cause disturbance and reduce the availability of suitable nesting habitats. In China wintering grounds, the main threats are from development and increasing human disturbance of wetlands in the Yangtze basin, the effects of the Three Gorges Dam on wetlands in the Yangtze basin, the proposed construction of a dam at the outlet to Poyang Lake and in Korea, the potential development of wetlands in the Demilitarised Zone. In China, wintering flocks occur outside of existing reserves, and are consequently at risk from hunting, direct disturbance, pollution from pesticide use and further loss of habitat due to agricultural expansion. At Cholwon, Korea, a switch from spring to autumn ploughing of rice paddies resulted in reduced foraging rates, potentially affecting overwinter survival. In Japan, the high proportion of individuals wintering at a single site at Izumi may render the population at greater risk from stochastic events or disease. Izumi is the main poultry region in Japan, and a disease outbreak among cranes could lead to over-reaction and extreme control measures due to economic risks to poultry farmers. The presence of livestock is likely to be detrimental because of disturbance, although it is possible that a limited amount of grazing could be important for maintaining habitat. Poisoning from pesticides and poaching is a growing issue.
Conservation
Conservation Actions Underway
It is legally protected in all range states. Protected areas have been established for its conservation, of which the most important are Khingansky, Muraviovka, Daursky and Lake Khanka(Russia), Daguur(Mongolia), Zhalong, Xingkai Hu, Xianghai, Keerqin, Poyang Lake, Dongting Lake and Shengjin Hu(China), Kumya and Mundok(North Korea), and Izumi-Takaono(Japan). Artificial feeding has resulted in an increase in the population wintering in Japan. A study into the migration routes and wintering areas used is being conducted by colour banding and attaching radio transmitters to individuals.
Conservation Actions Proposed
Establish transboundary protected areas at the Tumen estuary between Russia, China and North Korea and the Argun River between Russia and China. Secure the conservation status of Cholwon and the Han River estuary in the Demilitarised Zone. Increase the number of suitable wintering sites in Japan. Enforce conservation measures to minimise threats from the Three Gorges Dam and thousands of other dams to wetlands along the Yangtze and at Poyang. Extend or establish protected areas for breeding and wintering grounds as well as migratory stopovers, including Kumya, Lake Khanka-Xinghai, Poyang Lake, Sanjiang Plain, Sonbon and Bohai Bay. Control spring fires in the breeding grounds. Prevent poisoning from pesticides and poaching. Establish local crane conservation groups at small wintering and breeding sites. Establish a database combining the locations of crane records with details of existing reserve boundaries in order to identify priority sites. Ensure conservation measures are targeted to within 3km of roosting sites, as a recent study has shown that to be the maximum distance travelled by foraging individuals. Develop emergency response plans in case of avian disease outbreak at Izumi.