White-naped crane
The white-naped crane is a bird in the crane family, Gruidae. It breeds in shallow wetlands and wet meadows in northeastern Mongolia, northeastern China, and adjacent areas of southeastern Russia. It is a large bird measuring 112–125 cm long, about 130 cm tall, and weighing about 5.6 kg, with pinkish legs, a grey-and-white-striped neck, and a red face patch.
Taxonomy
The white-naped crane was formerly placed in the genus Grus, but a molecular phylogenetic study published in 2010 found that the genus, as then defined, was polyphyletic. In the resulting rearrangement to create monophyletic genera, four species: the sarus crane, the brolga, the sandhill crane and the white-naped crane, were placed in the resurrected genus Antigone that had originally been erected by German naturalist Ludwig Reichenbach in 1853.Description
The white-naped crane can be identified by its grey body, reddish face patch, white throat, and the white strip going from the back of its crown down its neck, or nape. Juveniles differ by having a brown head and a pale throat. While this crane does have other species in its genus with similar characteristics, it can be distinguished by the white nape that is not present in the other species.The white-naped crane emits a variety of different calls: a growling contact call, or high pitched call at short ranges, and loud calls which differ between sexes. The loud calls include aggressive guard calls and flight intention calls.
Distribution and habitat
The white-naped crane breeds in northeastern Mongolia, northeastern China, and adjacent areas of southeastern Russia, where a program at Khingan Nature Reserve raises eggs provided from U.S. zoos to bolster the species. Depending on the breeding location of the individual, they will migrate to different locations in the winter. The western breeding cranes will migrate through China to Poyang Lake while the eastern breeding individuals will migrate more south through Korea. Mongolia has been shown to hold at least 50% of the white-naped crane population.There are two main wintering populations of this species: one that winters near the Yangtze River in China, and the other in the Korean Demilitarized Zone. Counts are done multiple times throughout the winter to study their movement patterns.
The white-naped crane uses shallow wetlands and wet meadows for breeding sites. Generally, they can be found along lake edges and river valleys. They can also be found in mixed forest grasslands or lowlands. When foraging, they will use these sites but will also turn to farmlands for grazing.
Behaviour and ecology
Breeding
The white-naped crane breeds in the spring. They nest in pairs, and the nests tend to be located in areas of deeper water depth, which can provide protection against predators. Eggs are laid for two months, between April and the end of May. When chicks are born, they are a brownish-yellow colour with dark spots, and remain fledglings for 70–75 days. They will become sexually mature between the ages of 2 and 3 years old. When exhibiting parental behaviour, the crane will use a contact call, which is a lower frequency call used when the chicks are in close proximity to the parent.Diet
During the breeding season, their diet mainly consists of wetland plants, tubers and roots. While wintering or during migration, they will also feed on rice and cereal grains, as well as more waste grain. They will stand in place and dig for the deeper vegetation, which contrasts with the feeding behaviour of the red-crowned crane, which will walk around and pick at the surface vegetation. This difference is important as it allows both species of crane to occupy similar niches, without competition between them.Threats
The biggest threats faced by this species of crane is the ongoing loss of habitat, degradation of wetlands and climate change. Wetlands are consistently being converted to farmlands in China and eastern Russia. This also increases the disturbances from both people and livestock. More interactions with human populations are due to the fragmentation of the wetlands habitats, and this can result in both illegal hunting by humans as well as predation by free-roaming dogs. While the white-naped crane is not a game species, it is frequently disturbed by the hunting of other aquatic game species in the spring during its breeding season.Changes in climate have been affecting the hydrology and quality of their breeding sites: droughts have become more prevalent in wetlands, which impacts their nesting sites. Drier conditions have led to fires which have destroyed nesting sites and breeding sites, as well as eggs and young. The concentration of individuals in their breeding or overwintering sites has increased due to the loss of habitat, and this facilitates the spread of disease and death in their populations.