VU
Red-crowned Crane Grus japonensis



Justification

Justification of Red List Category
This species is classified as Vulnerable because the species suffered a rapid population reduction within the past three generations. While the island population in Japan has grown rapidly in recent decades into a large and now stable proportion of the global population, the continental Asian population has declined rapidly. Overall the species remains at high risk of extinction due to multiple threats affecting the small and still declining continental population and to the dependence of the population in Japan on active conservation. The overall current and future rate of population reduction has slowed as the stable Japanese population has increased as a proportion of the global population, such that future rates of reduction are suspected to slow further. However the overall population size remains small even with this population close to a predicted maximum size and, with the long generation length of the species, indications of population reductions impacting the global population size would require the swift reassessment of the species.

In order to prevent the extinction of the continental population coordinated action is necessary to ensure the continued and increased availability of extensive wetlands in which the species is protected from disturbance. Currently, the population wintering in China is very close to extinction, and that wintering in the Korean peninsula restricted to increasingly small patches of suitable habitat. The genetic distinction of the continental and island populations mean that preventing the regional extinction of the former is a priority for the long-term persistence of the species. Further loss and degradation of suitable wetlands through conversion to agriculture and industrial development must be avoided.

Population justification
Red-crowned Crane count data has been compiled with the assistance of the International Crane Foundation, IUCN Species Survival Commission Crane Specialist Group, the Red-crowned Crane Conservancy & species experts from each range country of the species (ICF/BirdLife International, unpublished data). The sum of all most recent counts in discrete wintering areas is 3,822 individuals; 1,900 in Japan in 2020 (Red-crowned Crane Conservancy 2020), 1,669 individuals in Korea (International Red-crowned Crane Network, unpublished data) and 353 in China (International Red-crowned Crane Network, unpublished data). The proportion of mature individuals has previously been estimated at around 60% (Jim Harris in litt. 2016). Accepting this as a precautionary proportion, the estimated number of mature individuals is 2,293, rounded here to 2,300 mature individuals.

Data for Japan is based on systematic monitoring to produce a total for each year (Red-crowned Crane Conservancy 2021). In 1973, the population was 213 individuals, whereas in 2020-21 it was 1,900 individuals (Red-crowned Crane Conservancy 2021). The increase in the Japan population has been very rapid for a bird with such a long generation length and has been driven by the provision of winter food at feeding stations and high level of protection granted to the species. Recent attempts to reduce the dependency of the population on the few feeding sites appear to have resulted in the stabilisation of the population at around 1,800-1,900 individuals: 1,850 were counted in 2015-16, falling to 1,600 in 2017-18 before climbing back to 1,900 in 2020-21 (Red-crowned Crane Conservancy 2021). This results in an estimated increase in the Japanese population of 780% over the past three generations. There is the expectation that this population will be managed such that numbers do not grow further, and numbers may reduce slightly as efforts to reduce the dependence of the population on supplementary feeding take effect.

The continental population is divided into those wintering in China and those wintering in the Korean Peninsula. The population in China has declined rapidly over at least the past three decades. Fewer data are available, however systematic counts have been attempted in some years. In the early 1960s, more than 1,500 individuals were estimated to be wintering in coastal Jiangsu (Shi Zerong and Wu Lingxiang 1987) and while this was the most significant wintering area there were still numerous additional sites occupied by small numbers, including Hongze Hu, Gaoyou Hu, Shaobo Hu in Jiangsu, Xinglong Sha of southern Jiangsu and eastern tidal flats of Chongming Islands in Shanghai, and Lake Shijiu Hu in Anhui (S. Chan in litt. 2021). As such, the total wintering population is assumed to have been considerably more than 1,500 individuals at the start of the past three-generation period (1973). While small numbers have continued to be observed at some of these sites (such as recent observations of a family of four at Shijiu Hu (Anhui Bird Watching Club 2021), these sites no longer hold a regular wintering population and the species had been lost from most by the late 1980s (S. Chan in litt. 2021). With the concentration of birds at few wintering sites more recent estimates of numbers are considered more accurate. A total of 1,163 individuals were estimated in winter 1999-2000, almost all (1,128) of which were at Yancheng National Nature Reserve (Wang et al. 2008). This was the highest count at the site of the annual numbers supplied for 1981-82 through to 2019 (Wang et al. 2008, Wang et al. 2020, Q. Fawen in litt. 2021). It is assumed that the increases up to 1999-2000 can be assigned to a concentration of individuals at Yancheng NNR. Most other individuals are present at the Huanghe/Yellow River Delta, with only small numbers elsewhere (International Red-crowned Crane Network 2021). Subsequent to this high point, an alarming decline has taken place; estimated totals wintering in China were 737 individuals in 2014-15, 600 in 2016-17, 580 individuals in 2017-18 and only 353 in 2019-20 (International Red-crowned Crane Network, unpublished data).
Accounting for the uncertainty in the past size of the Chinese wintering population through back projection of the counts in 1999-2000 and 2019-20 (Wang et al. 2008 and International Red-crowned Crane Network, unpublished data), the rate of decline here is estimated to have been 94.2% over the past three generations (48 years: 1973-2021). This projects that the size of this population was 5,382 individuals in 1973, making it by far the largest wintering population at the time. There is anecdotal information that suggests the population may have been large in the mid-20th century: flocks of more than 100 were reported to be regular at wetland sites destroyed in the 1970s (BirdLife International 2001) that are assumed to be additional to the more than 1,500 counted at Yancheng in the early 1960s (Shi Zerong and Wu Lingxiang 1987).

Counts of the Korean Peninsula wintering population have increased considerably since the mid-1990s, when 575 were estimated to be present spread across DPR Korea and Republic of Korea (Meine and Archibald 1996). 1,019 individuals were counted in 2009-10, 1,083 individuals in 2011-12, but recently a rapid increase has occurred, with 1,251 in 2017-18, 1,401 in 2018-19 and 1,669 individuals in 2019-20 (International Red-crowned Crane Network, unpublished data). However, none are believed to have wintered in DPR Korea since 2013-14 at the latest (Momose and Momose 2019) and within the Republic of Korea, feeding stations have concentrated birds at few sites. As in Japan, the current population is considered to be at or near a maximum that can be supported in the habitat remaining in the area, but likely exceeds that which would be supported by natural food supplies. Consequently it is suspected that the 2019-20 value is a peak number and the population will begin to reduce in next few years. Using the 1995-96 and the 2019-20 population estimates, but fixing the latter as the value for the assessment year (2021) results in an estimated increase over the past three generations of 606%, while using the 2009-10 count to project the past population gives a 611% increase. However, it is uncertain whether numbers wintering in Korea have been gradually increasing since the 1970s, or whether a larger number were present with only a recent increase, as there are no counts prior to 1994-95. Historic references suggests the species was common in North Korea in the late 19th century (BirdLife International 2001), but there is no further information until the mid-1990s.

Trend justification
The population trend in Japan has been a rapid increase whereas that on the continent has been mixed, with rapid decline in those wintering in China and an increase in birds counted in Korea (Momose & Momose 2019). The population trend for each of the three sections of the population has been estimated using the count data outlined under population size. For the Japanese population, with data available for the complete three-generation period (Red-crowned Crane Conservancy 2021), there has been an increase of 780% over the past three generations, from 213 individuals in 1973-74 to 1,900 individuals in 2020-21. There is the expectation that this population will be managed such that numbers do not grow further, and may reduce slightly as efforts to reduce the dependence of the population on supplementary feeding take effect. 

The continental population is divided into those wintering in China and those wintering in the Korean Peninsula. The population in China has declined rapidly over at least the past three decades. Accounting for the uncertainty in the past size of the Chinese wintering population through back projection of the counts in 1999-2000 and 2019-20 (Wang et al. 2008 and International Red-crowned Crane Network, unpublished data), the rate of decline here is estimated to have been 94.2% over the past three generations (48 years: 1973-2021). This projects a population size of 5,382 individuals in 1973, making it by far the largest wintering population at the time. This is a precautionary approach, given the estimate of more than 1,500 wintering in Jiangsu in the early 1960s (Shi Zerong & Wu Lingxiang 1987) and assumes the rate of reduction has been similar over the whole time. If the total given for Jiangsu represented 50% of the wintering population in China (on the basis that it was considered the largest wintering population), then the rate of reduction is considerably lower, at 85%, and the influence on the overall rate of population reduction is also much reduced.
For the Korean wintering population, feeding stations have concentrated birds at few sites and as in Japan the current population is considered to be at or near a maximum that can be supported in the habitat remaining in the area, but likely exceeds that which would be supported by natural food supplies. Consequently it is suspected that the 2019-20 value is a peak number and the population will begin to reduce in next few years. The longest span of reliable counts is between the 1995-96 and the 2019-20 counts: 575 (Meine & Archibald 1996) and 1,669 (International Red-crowned Crane Network 2021). Fixing the latter as the value for the assessment year (2021) (assuming the population is not going to increase further) results in an estimated increase over the past three generations of 606%. Using a more recent but potentially more precise count (due to concentration of individuals) from 2009-10 to project the past population results in a similar increase of 611%.

Overall the projected large past population size of the Chinese wintering population and its extremely rapid decline outweighs the increases in other wintering populations and the estimated rate of reduction for the species (using the count data outlined above) over the past three generations is 33.4% between 1973 and 2021. However, with every year the past rate of reduction falls sharply as the bulk of the population now resides in the two stable populations. For the shortest projection to the future (1974-2022), the estimated rate of reduction calculated in the same way as above (keeping the Japanese and Korean values fixed at the most recent count value) is 30.6%. One further year into the future and the rate of reduction falls below 30% over three generations. Estimating past rates of reduction it appears most likely that the overall past rate of population reduction last exceeded 50% for end years between 2007-2012, unless the 1960s Chinese wintering population was much larger than has been projected here.

With the apparent stabilisation of the populations in Japan and Korea, the ongoing rate of decline in the population wintering in China means that there is now an estimated continuing decline rate over three generations (1974-2022) of 30.6%. Over a shorter timeframe the rate of decline is much lower (and is an increase over one generation) as the recent rapid increase in the rest of the population outweighs the declining proportion. The rate of the continuing decline is expected to slow rapidly in the future as the three generation period no longer includes the period of rapid decline.

Distribution and population

Grus japonensis breeds in south-eastern Russia, north-east China, Mongolia (where it was first recorded in 2003 [O. Goroshko in litt. 2003]), and eastern Hokkaido, Japan (BirdLife International 2001).  The global population is split into continental and island groups, and the continental is split into birds using the eastern flyway and those using the western flyway. The eastern population is stable or slightly increasing, whilst the western flyway is severely declining (Su and Zou 2012). The Russian and Chinese populations mainly winter in the Yellow river delta and the coast of Jiangsu province, China, and the Demilitarised Zone, Democratic People's Republic of Korea/Republic of Korea, although none are thought to have been regularly wintering in DPR Korea for at least 8 years (Momose and Momose 2019). Important staging areas include the Liao River Estuary National Nature Reserve (NNR) and the Yellow River Delta NNR (Momose and Momose 2019). The Japanese population is non-migratory and was confined to Hokkaido, but has been expanding its range as numbers have increased: a pair wintered on Kunashiri Island for the first time in 2015-16 (Momose and Momose 2019).

For the continental population there is evidence of increasing concentration of birds at fewer suitable sites in both breeding areas and in wintering sites (Jiang et al. 2012, Wang et al. 2020). Breeding census data in the Sanjiang Plain shows numbers to be stable between 1984 and 2008, but with increased concentration to fewer localities due to land use changes (Jiang et al. 2012). Elsewhere the species no longer breeds at Keerqin, Xianghai and Momoge NNRs in China (Momose and Momose 2019), while in Russia there is concern that there is now insufficient habitat for the species to adjust to medium-term cyclic rainfall patterns (Momose and Momose 2019). For wintering birds, in Jiangsu only 6–7 sites out of 28 previously occupied sites were occupied in 2008, estimated to represent only 8% of the occupied range in the 1980s (Su and Zhou 2012).

The resident population in Japan has increased to c.1,900 birds (Red-crowned Crane Conservancy 2021), but this growth is not expected to continue due to habitat limitations and change in winter feeding methods by the Ministry of the Environment, Japan, to reduce high concentrations of cranes.

Ecology

In Russia and China, it breeds in grass, reed, and sedge marshes. In winter and on passage, it occurs in wetlands, including tidal flats, saltmarshes, rivers, wet grassland, saltpans and aquaculture ponds and in artificial feeding grounds (in Japan). Tidal mudflat crab Helice tientsinensis has been found to be an important food source during migration, alongside smaller numbers of  other crab species (Eriocheir sinensis, Macrophthalmus dilatatum), fish and ragworms Hediste diversicolor (Li et al. 2014). It also feeds on croplands, where it is vulnerable to poisons (Y. Momose in litt. 2016). Level of human disturbance and flock size has been found to influence time spent being vigilant by this species wintering in the Yancheng Biosphere Reserve, China (Wang et al. 2011). Landscape and plot level factors are important in explaining crane occurrence, including presence of seepweed tide flats, tamarisk-seepweed tidal flats, reed marshes and other natural wetlands. In the Yellow River Delta Nature Reserve, China, the species was negatively associated with roads (Cao et al. 2015).

Threats

The key threat is the loss and degradation of wetlands in its breeding and wintering grounds, principally for conversion to agriculture, but also aquaculture, industrial and economic development (J. Harris in litt. 2007, 2009; Momose and Momose 2019). Due to habitat loss, the winter range in China is now only 8% of the extent present in the 1980s (Su and Zou 2012), resulting in high concentrations of cranes at few sites (Wang Qi-shan 2008). Further impacts on the wintering habitat comes from the invasive cordgrass Spartima alterniflora which has made a large extent of the feeding areas in the intertidal zone unsuitable for the species (Liu et al. 2009). Wintering areas in the Civilian Control Zone in Korea are increasingly cluttered and fragmented by agricultural infrastructure and powerlines, plus agricultural activity is now permitted for more of the year (Momose and Momose 2019). Many breeding areas are impacted by changes in hydrology due to water control and diversions (Momose and Momose 2019). Rainfall patterns in the breeding grounds appear to follow a 30-year cycle, and the current dry period has meant birds, people and livestock have had to depend on ever smaller areas of wetland, also resulting in increased pressure to divert water from rivers and lakes (Harris 2008). Water control has also led to the loss of suitable habitat within Xianghai and Keerqin NNRs, resulting in the abandonment of these protected areas by the species (Momose and Momose 2019). Dam construction on Hailaer River in China, and the Zeya and Bureya Rivers plus tributaries in Russia has changed the processes maintaining wet habitats, each to the detriment of breeding Red-crowned Cranes (Momose and Momose 2019). Future construction of dams on the Amur river and its tributaries is a threat (W, Heim in litt. 2016). Additionally, spring fires destroy suitable nesting grounds, and lower water levels allow predators access to nests and destroying suitable breeding sites (J. Harris in litt. 2007, 2009). The water level at the key site of Zhalong Nature Reserve (China) has been impacted following the construction of canals, and the lowered water table has allowed fires to spread across the area (Momose and Momose 2019). But inappropriate wetland restoration at Zhalong has also been recorded as causing inappropriately-timed floods leading to nest failure (Wang and Li 2008).

Human disturbance has been so high as to prevent individuals from nesting in some areas (J. Harris in litt. 2009) and has been found to influence vigilance behaviour (Wang et al. 2011) and exacerbated the impact of predators (Momose and Momose 2019).

There is high adult mortality in some continental wintering areas which is apparently due to poisoning (Harris and Mirande 2013); the species has been found to carry high levels of heavy metal contamination (Teraoka 2008), and the incidence of poisoning has been increasing in recent years (Harris 2008, Su Liying et al. 2008, Su and Zou 2012, Luo et al. 2016).  Poaching has also been suggested as a threat (Su Liying et al. 2008) and some cranes and their eggs are taken for the captive trade (Su and Zou 2012). In the Demilitarised Zone in the Korean Peninsula, the shift to autumn ploughing is reducing access to waste grain (Lee et al. 2007), resulting in the species disappearing from wintering sites in the DPRK (Momose and Momose 2019). Further shifts in crops (e.g. from Job's Tears and corn Zea mays to ginseng in Korea or increased cotton growing in China [Momose and Momose 2019]) further restricts food availability. There is great uncertainty regarding the long-term fate of the crane habitat on the Korean Peninsula, whatever the political future delivers. 

In Japan, the concentration of birds at feeding stations means there is a risk of disease, especially given the low genetic diversity of the population, which passed through a bottleneck in the 1950s (J. Harris in litt. 2007, 2009; Wang Qi-shan 2008). 

Conservation actions

Conservation Actions Underway
CITES Appendix I and II.  CMS Appendix I and II.  Part of the European Endangered [Species] Programme of the European Association of Zoos and Aquaria.  It is legally protected in all range states. Key protected areas include Khingansky, Muraviovka and Lake Khanka (Russia), Zhalong, Xianghai, Hui River, Shuangtai Hekou, Yellow River delta and Yancheng (China), Kumya and Mundok (DPR Korea), Kushiro, Akkeshi-Bekanbeushi and Kiritappu (Japan). All cranes surveyed in the Sanjiang Plain region by Jiang et al. (2012) were recorded within one of seven National Nature Reserves, which collectively cover 6,994 km2. Surveys of the wintering population in China have been carried out since 2006 (Su Liying et al. 2008, International Red-crowned Crane Network, unpublished data). The International Red-crowned Crane Network (IRCN) was established in the fall of 2009 following three years of discussion at international meetings hosted by the then Tancho Protection Group, now the Red-crowned Crane Conservancy. Artificial feeding has been set up at some sites (Wang Qi-shan 2008).

Conservation Actions Proposed
Identify breeding times during which particularly stringent protection rules should be implemented, as has been done at Liaoning Shuangtai Estuary (Zou Hong-fei et al. 2008). Improve general monitoring procedure, with complete censuses, satellite tracking and aerial counts. Determine Area of Occupancy to a more accurate level. Initiate a study of heavy metal contamination on the mainland (J. Harris in litt. 2009). Expand the area/number of wintering sites in Japan. Establish a transboundary protected area at Tumen estuary, between Russia/China/North Korea. Secure the conservation status of the Cholwon and Han estuary in the Demilitarised Zone. Strengthen management of protected areas on the Sanjiang plain (China), reducing human disturbance. Halt tidal-flat reclamation along the Yancheng coast (China), and control the highly invasive cordgrass Spartina alterniflora. Improve management of wetland restoration at Zhalong, to prevent floods from causing breeding failure (Wang and Li 2008). Prevent poisoning from pesticides and poaching. Control fires in the breeding grounds. Establish interest groups and a communications organisation for crane conservation in China (Wang Qi-shan 2008) and extend captive breeding programmes for future reintroduction and population supplementation.

Identification

150 cm. Very large, predominantly white crane. Black face and neck, but with white patch extending from behind eye to nape. Red crown. White primaries and black secondaries and tertials. Similar spp. Siberian Crane G. leucogeranus and Whooping Crane G. americana have black primaries and white necks. Black-necked Crane G. nigricollis has grey body. Voice High-pitched, penetrating calls.

Acknowledgements

Text account compilers
Martin, R.

Contributors
Chan, S., Goroshko, O., Harris, J., Li, Z.W.D., Parilov, M., Smirenski, S., Lee, S., Momose, Y., Millington, S., North, A., Taylor, J., Peet, N., Khwaja, N., Benstead, P., Mahood, S., Symes, A., Allinson, T, Mirande, C., Morrison, K., Archibald, G., Craig, C., Momose, K., Lee, K., Qian, F., Ilyashenko, E., Seiji, H. & Qian, Y.


Recommended citation
BirdLife International (2022) Species factsheet: Grus japonensis. Downloaded from http://www.birdlife.org on 26/06/2022. Recommended citation for factsheets for more than one species: BirdLife International (2022) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 26/06/2022.