Northern Prairie Wildlife Research Center
Scott R. Swengel
Population Numbers and Trends
Historic and Present Distribution
Distribution by Country
Habitat and Ecology
Current Conservation Measures
Priority Conservation Measures
The Red-crowned Crane is the second rarest crane species, with a total population
in the wild of 1,700-2,000 birds. They breed in large wetlands in temperate East
Asia and winter along rivers and in coastal and freshwater marshes in Japan, China,
and the Korean Peninsula. There are two main breeding populations: a migratory
population on the East Asia mainland (northeastern China and Russia) and a resident
population on the island of Hokkaido in northern Japan. In the winter, the mainland
population divides into two or three wintering subpopulations (depending on whether
wintering birds in the Korean Peninsula are considered a single group). The total
population has fluctuated over the last century, probably reaching its lowest
point in the years following World War II. Although the species has recovered
in some areas, a substantial amount of habitat has been lost to agricultural development
and other human economic activities. The species is classified as Endangered under
the revised IUCN Red List Categories.
Red-crowned Cranes prefer to nest and feed in marshes with relatively deep water, and will nest only in areas with standing dead vegetation. They are generalist feeders and prefer wetter feeding sites, but also forage along dikes and in croplands. On their wintering grounds they feed on waste (or human-provided) grain, and on aquatic plants and animals in coastal marshes and open watercourses.
Habitat loss and degradation constitute the principal threats to the species. Continued agricultural and industrial development affects breeding areas in Hokkaido, the Sanjiang Plain in northeastern China, and the Amur River basin in Russia. Water control and diversion projects (including proposed dams on the Amur River and on the Yangtze River) and the potential for conflict or development in the Korean Demilitarized Zone pose large-scale threats to breeding, migration, and wintering habitat. Other anthropogenic threats include disturbance, intentional setting of fires, and overharvesting of wetland resources in key breeding areas.
Conservation measures that have been taken to protect the species and its habitats include: international agreements and cooperative research (especially involving migration routes); establishment of protected areas to safeguard habitat and minimize disturbance; development of winter feeding stations and the marking of nearby utility lines in Japan; regular surveys on breeding and wintering grounds; preparation of a Population Habitat and Viability Analysis for the species; cooperative conservation and education programs focused on the species; and several limited reintroduction efforts.
Priority conservation measures include: adoption of an umbrella international agreement on the cranes of East Asia; continued international cooperation in research on migration routes and patterns; protection of key habitats on the Korean Peninsula; adoption of improved methods of resource management (including both wetland resources and agricultural lands) in and around existing protected areas; annual surveys of the main wintering populations; research on the impacts of human resource use on breeding habitats and breeding behavior; development of education programs to encourage farmers and other local residents to adopt sustainable resource use practices; and development of a comprehensive recovery plan for the species.
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|North Korea||300-350||Increasing||J. R. Chong pers. comm.|
|South Korea||200-300||Unknown||Pae and Won 1994,
F. Kaliher pers. comm.
|Japan (Hokkaido)||594||Increasing||Kushiro ECRPT 1993,
H. Masatomi pers. comm.
|Total||1700-2000||Stable to declining
(based on loss of
The highest counts for mainland regions come from different years. Thus, the total presented here assumes some movement between alternate wintering grounds among years. In addition, 281 of those included here in the South Korea data were found in the Demilitarized Zone (DMZ) (Kaliher 1993). A significant number of these birds might also be included within North Korea’s total.
There are few historical data on the mainland population. Studies from China suggest that the subpopulation there was stable from 1979-1984 (Feng and Li 1985, Ma and Jin 1987), but there have been losses in land area used by the cranes (see below). Winter counts at Yancheng have varied from 546 in 1990-91 to 775 in 1991-92, with several other recent counts of 530-775 (ICF 1990, 1991; Wang 1995). A small Liaoning subpopulation may be declining.
The North Korean wintering subpopulation appears to be increasing (J. R. Chong, pers. comm.), while the South Korean numbers have remained stable over the years (Kaliher 1993c). This suggests a possible increase in birds breeding in the far northeast part of the range, or a shift in wintering ground choice.
Masatomi (1982a) reviewed historical information on Red-crowned Crane populations in Japan. The Hokkaido population has increased steadily since winter counts began. When the first feeding station was established in 1952, a December count recorded 33 birds (Masatomi 1981b). The population had grown to about 600 by the winter of 1993-94 (Kushiro ECRPT 1993, H. Masatomi pers. comm.). Improved winter survivorship is probably the main factor behind the population increase, since the recruitment rate has fallen over the past 20 years and is now stable (Masatomi 1981b, Momose and Nakamura 1983, Masatomi 1991). From 1986-87 to 1991-92 the population grew at 4.85% per year, somewhat lower than in the previous six years. The proportion of juveniles in the winter population averaged 11.1% during this period, similar to the preceding six-year period (Masatomi 1993a, Masatomi and Momose 1995). The marking of Hokkaido’s utility lines beginning in 1971 has also greatly decreased the incidence of crane mortality (see current “Habitat Protection and Management” section below).
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|IUCN category||Endangered, under criterion C1|
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Red-crowned Cranes currently breed in northeastern China (Inner Mongolia and Heilongjiang, Jilin, and Liaoning Provinces) and adjacent parts of Russia, and are year-round residents on the island of Hokkaido in Japan (Su 1993, Fan et al. 1994, Ma and Li 1995, Shibaev and Andronov 1995, Masatomi and Momose 1995). There are three main breeding areas. More than half of the population breeds in northeastern China and adjacent Russia. The species occurs rarely in the summer in far eastern Mongolia (Bold et al. 1995). The non-migratory birds of Hokkaido—about one-third of the population—represent the remainder. One pair of birds is known from the southern Kuril Islands. Wintering areas are on Hokkaido, on the Korean Peninsula (primarily within the DMZ), and in coastal Jiangsu and nearby parts of China.
The historical record is inadequate for reconstructing the Red-crowned Crane’s former range in China (Su 1993). In the past Red-crowned Cranes may have wintered in southern Liaoning, China (see Johnsgard 1983), but these could be migration records. Red-crowned Cranes do not winter in this area today (Su L. pers. comm.). In recent years, the breeding range in the Sanjiang Plain (Heilongjiang) has become smaller and more isolated with increasing agricultural development (Su 1992). In the Dulu River Region, for example, the numbers of cranes and nests have dropped from 90 and 17 in 1984 to near zero in 1994 (Harris 1994c). The main breeding area in the Zhalong region of Heilongjiang shifted to the north between 1981 and 1984 (Feng and Zhao 1991). Mongolia had at least one nesting record in the 1920s, but the species no longer nests there (Bold et al. 1995).
In Korea, Red-crowned Cranes were reported to be common as far south as Seoul in the late 1800s (Austin 1948). In Japan the breeding range included southwestern, and perhaps the northern tip, of Hokkaido, until about 1890 (Masatomi 1981a, Archibald 1987). Some cranes also migrated from Hokkaido to Honshu, Japan, wintering there regularly until after 1850 (Masatomi 1981a). Red-crowned Crane habitat (especially breeding habitat) in Japan has gradually decreased due to development pressure, causing cranes to breed in lower quality sites (Archibald 1987) and in ever greater densities in the areas that remain (Masatomi 1993b).
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|China||B, M, W|
|North Korea||M, W|
|South Korea||M, W|
|B = Present during breeding season|
|M = Present during migration|
|R = Year-round resident|
|W = Present during winter|
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Red-crowned Cranes are highly aquatic cranes with large home ranges (Masatomi 1981a, 1993b). They feed in deeper water than sympatric cranes, using a “walk-and-peck” feeding technique more than repeated probing and digging (Su 1993). From summer to fall they forage regularly on pasture lands in Japan, In winter they use coastal salt marshes, rivers, freshwater marshes, rice paddies, and cultivated fields. Most of the birds breeding in China migrate along the coast of the Bo and Yellow Seas between their breeding grounds and their wintering grounds in Jiangsu. Most of the Russia-breeding birds migrate through North Korea between their breeding grounds and wintering grounds in the Korean Peninsula.
Reported summer home range sizes are 2.6 (+/- 0.6) km2 in China, 1-7 km2 in Japan, and 4-12 km2 in Russia (Winter 1981, Kitagawa 1982, Andronov et al. 1988, Su 1993). Families may use <1% of the home range at certain times of the breeding season (Kitagawa 1982), or use wholly different areas for feeding and nesting (Winter 1981). In high quality habitat, nesting densities of 0.05/km2 in Russia, 0.21-0.24 pairs/km2 in China, and 0.06-0.82/km2 in Japan have been recorded (Winter 1981, Su 1993, Masatomi et al. in press b). Winter ecology, habitats, and behavior in China and Korea are described by Li and Feng (1985), Chong (1988), Won (1988), Zhou (1988), Kaliher (1993c, 1994), Pae and Won (1994), and Halvorson and Kaliher (1995).
Smirenski (1980), Winter (1981), Kitagawa (1982), Andronov et al. (1988), Masatomi (1993b), and Su (1993) have described the species’ nesting and feeding habitats and preferred food items at different times in the summer range. Nesting Red-crowned Cranes show a significant preference for wetter wetland types, such as reed-sedge marsh, reed marsh, cattail marsh, and floating reed-sedge mat in China; these, along with croplands and dikes, also comprise the preferred feeding habitats (Su 1993). In Russia, they use vast cottongrass-sedge bogs and similar habitats (Smirenski 1980, Winter 1981). Red-crowned Cranes select uncut marsh habitat over cut marsh habitat for feeding (Su 1993).
Red-crowned Cranes are generalist feeders, eating a wide variety of insects, aquatic invertebrates, fish, amphibians, and rodents, as well as reeds (e.g. Calamagrostis spp., Sagittaria spp., and Potamogeton spp.), grasses, heath berries, corn, and other plants during the warm season (Andronov et al. 1988, Masatomi 1993b, Su 1993). They consume upland insects more in July-August than in other seasons (Andronov et al. 1988). The winter diet varies depending on the site. In Hokkaido, they feed on human-provided corn and on aquatic plants and animals in unfrozen watercourses. In Korea, the diet consists of waste grain and animal food items. In the coastal salt marshes (from damp to water-covered areas) of China, they feed on aquatic invertebrates, plants, and some human-provided grain (Won 1981, Masatomi 1993b, J. Harris pers. comm.).
Nests are built on wet ground or in shallow water up to 44 cm deep in Japan, and to 20-50 cm deep in Russia (Andronov et al. 1988, Masatomi 1993b, H. Masatomi pers. comm.). The cranes nest in areas with standing dead reeds 30-200 cm tall (Winter 1981, Smirenski 1988), and preferentially place nests in areas not cut the previous winter (Su 1993). Fire is the leading cause of nest destruction, and often prevents nesting from taking place at all (Winter 1981; Smirenski 1980, 1988). Usually two eggs are laid. The incubation period is 29-34 days, and chicks fledge at about 95 days.
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The conservation status of Red-crowned Cranes in Japan is described by Inouye (1981), Masatomi (1981a, 1982b, 1993b), Momose and Nakamura (1983), and Archibald (1987). Won (1981, 1988), Pae and Won (1994), Kaliher (1993a, 1993, 1993c), and Holvorson and Kaliher (1995) discuss crane conservation in the Republic of Korea. Flint and Smirenski (1978) and Smirenski (1989a) have reviewed the status and conservation of cranes in Russia. Harris (1989, 1992a, 1994a) describes recent crane conservation activities in China, and provides additional information (1991a) relevant to the status of the Red-crowned Crane. Wang (1995) describes the status of the species at its main Chinese wintering area in Jiangsu Province.
The Red-crowned Crane is seriously threatened by loss of habitat throughout its range. Economic development, especially agricultural expansion, river channelization, deforestation, and road building, is destroying many of the breeding wetlands in Hokkaido (Momose and Nakamura 1983, Archibald 1987, Masatomi et al. 1990), which support more than a quarter of the population. In China, agricultural development of breeding and wintering grounds is a critical threat. Between 1979 and 1984, two-thirds of the marshland in the Dulu River region of northeastern China, a major breeding area, vanished due to cultivation (Feng and Li 1985). By 1994, nearly all the breeding Red-crowned Cranes in this region had disappeared or gone elsewhere (Harris 1994c). Continued agricultural development of the Sanjiang Plain in Heilongjiang Province, another important breeding area, constitutes a major threat to the mainland population (Su 1992, Harris 1994c). Development of oil wells and agriculture threaten the Panjin Marsh, the species’ southernmost breeding area in China (Kanai et al. 1993), and the wintering grounds in coastal Jiangsu, where 40% of all Red-crowned Cranes winter (Wang 1995).
In and around Zhalong Nature Reserve, reeds are currently being harvested at a level that depletes the species’ preferred nesting habitat, and much of its feeding habitat (Su 1993). Smaller amounts of reed cutting might maintain a better mix of habitats; ideal habitat would have some areas of reeds cut (in winter), but others left uncut. In contrast to past practices, farmers who benefit directly from their crops now chase cranes out of fields more actively (Su 1993). Overfishing may also be limiting the food base in the Zhalong wetlands (Harris 1989, Su 1993).
Water control and diversion projects also threaten the species’ habitat. Water diversions reduce the area of suitable nesting habitat at the Zhalong (Harris 1989) and Hong He (Harris 1994c) Nature Reserves. By altering sedimentation processes, the proposed Three Gorges Dam on the Yangtze River may result in the loss of the wintering habitat in the coastal marshes of Jiangsu (in a manner similar to the current loss of lands in the Mississippi River Delta). This project would also change, and perhaps even destroy, the water bird habitat at Poyang, Dongting, and Shengjin Lakes, the three most important wintering sites for Siberian, Hooded, and White-naped Cranes in China.
Habitat-related threats are also of serious concern on the Korean Peninsula (Halvorson and Kaliher 1995). The Korean DMZ now functions as a de facto protected area. Armed conflict in this area would be disastrous for cranes and other forms of wildlife that find refuge there. If, on the other hand, North and South Korea unite (and unless special measures are taken), the area is likely to be developed rapidly and to disappear as a crane wintering area (see the White-naped Crane species account in this volume). Other problems in South Korea include human disturbance of cranes, ineffective environmental protection policies, increasing land use pressures on cranes, and lack of professional experience in wildlife management (Pae and Won 1994, Halvorson and Kaliher 1995).
Flint and Smirenski (1978), Borodin et al. (1984), and Andronov (1988) report that drainage of wetlands, agricultural fires, and cattle grazing have reduced the species’ nesting habitat in Russia. About 40% of Red-crowned chicks in Russia fail to fledge; combined with the inability of some pairs to find suitable nest sites because of human activities, this may explain the very low proportion (1-3%) of juveniles in the South Korean wintering population (Smirenski 1988). Large scale threats are of immediate concern in the Amur basin. Seven dams have been proposed for the Amur River; if built, these would alter water levels at critical times of the year for wildlife, and would have harmful effects on the cranes’ food base (Smirenski 1992a, Smirenski et al. 1995).
Harassment by people, agricultural fires, and poisoning from pesticide-treated grain directly harm Red-crowned Cranes in Russia (Flint and Smirenski 1978, Borodin et al. 1984, Andronov 1988). Hunting of cranes has increased recently in Russia due to the immigration of people with different cultural traditions (Smirenski 1992b). In Japan, tourism and recreational activities pose a threat to the breeding behavior of the species (H. Masatomi pers. comm.). In China, disturbance of nests after a critical point in the breeding season can prevent Red-crowned Cranes from renesting successfully (Su and Zhou n. d.). Egg collecting also occurs in China (G. Archibald pers. comm.). At least 17 Red-crowned Cranes have recently been poisoned by duck hunters at Yancheng (Wang 1995).
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Note: many of the measures described in this section have also benefitted the Demoiselle, Siberian, White-naped, Hooded, and Eurasian Cranes of East Asia.
Legal and Cultural Protection
It is illegal to hunt Red-crowned Cranes in all of the nations where they normally occur. They are designated as natural monuments or nationally protected birds in all of the countries where they breed or winter. Kushiro ECRPT (1993) provides a thorough review of the laws and international treaties under which the species is protected in Japan.
International Agreements and Cooperation
The Siberian and White-naped Crane species accounts in this volume describe international agreements and cooperative ventures that are also relevant to the conservation of the Red-crowned Crane. China, Japan, and Russia have signed the Ramsar Convention. Since 1984 these same countries have cooperated in exchanging information about summer and winter surveys of Red-crowned Cranes. Dr. Hiroyuki Masatomi (1985a, 1988), with support from the Wild Bird Society of Japan and other organizations, has periodically compiled these data. Japan, China, Russia, and North and South Korea are cooperating on international radiotelemetry studies for the Red-crowned and other cranes (e.g., Higuchi 1993; Chong et al. 1994; Higuchi et al. 1992, 1994b, 1995).
During the breeding season, wetland reserves in China support more than 500 Red-Crowned Cranes (Harris 1992a). These are (from those with the largest breeding populations to those with the smallest): Zhalong (in Heilongjiang Province), Shuangtaizi (Liaoning), Xingkai Hu (Heilongjiang), Honghe (Heilongjiang), Xianghai (Jilin), Keerqin (Inner Mongolia), Changlindao (Heilongjiang), Watonghe (Heilongjiang), Chaganhu (Jilin), Momoge (Jilin), Dalainor (Inner Mongolia), and Dalinor (Inner Mongolia) Nature Reserves (Harris 1992a, Ma and Li 1994). Reserves have been proposed for the Hui River area of Inner Mongolia (Ma and Li 1991) and the Sanjiang Plain in Heilongjiang (Harris 1994c). Russia has important breeding sites within Lake Khanka, Khinganski, and Ganukan Nature Reserves (Archibald and Mirande 1985, Andronov 1988). Other Russian protected areas supporting Red-crowned Cranes include Ulma, Jashina, Muravienka, Amursky, Bolon, Urmi, Chauka, Kurilski, Zhuravlini, and Muraviovka (a private reserve) (Smirenski 1985).
The Tanyang and Huanghe Delta Nature Reserves protect the migration stopover site at the mouth of the Yellow River in Shandong Province, China (Ma and Li 1994, J. Harris pers. comm.). Stopover sites along the Tumen River and in other areas remain poorly known, and are not protected (Shibaev and Surmach 1994).
Yancheng Nature Reserve in Jiangsu Province, China, protects the habitat of the largest wintering subpopulation, which reached a high of 775 in 1991-92 (Wang 1995). North Korea has designated four areas—Kangryong, Panmun, Kumya, and Anbyon—as natural monuments to protect wintering Red-crowned Cranes (Sonobe 1987, J. R. Chong pers. comm.). The Choelwon Bird Reserve provides protection for a small portion of the wintering grounds in South Korea. The Korean DMZ functions as a protected area due to its relative lack of intensive economic development.
Portions of the breeding grounds on Hokkaido are designated Natural Monuments (Kushiro ECRPT 1993, Masatomi 1993b), but much of the habitat remains unprotected. After at least 17 years of stable breeding numbers at Kushiro Mire, which is under the strictest protection in Japan (part of the area was designated a national park in 1987), the number of pairs increased from 22 to 48 between 1988 and 1992 (Masatomi 1993b). The marsh has also been registered as a Wetland of International Importance under the Ramsar Convention (Kushiro ECRPT 1993).
Habitat Protection and Management
In many protected areas, such as Zhalong, Muraviovka, and Khinganski, agricultural activity in the marshes has been or is now being restricted in order to promote crane nesting. Su (1992, 1993) studied the effects of several human activities and management methods, and found that both disturbance by humans and overharvesting of reeds were detrimental to crane nesting efforts.
Tsujii (1994) reviews the conservation status and needs of the wetlands used by the Hokkaido population. Active habitat management in the Korean peninsula has been limited. See Pae and Won (1994) and Halvorson and Kaliher (1995) for discussion of the conservation status and needs of key crane habitats in the south and along the DMZ.
In Japan two active habitat management measures have allowed the Red-crowned Crane population to increase. First, the winter feeding station established in 1952 (and several others that have since been built) have helped the Hokkaido population to grow steadily by improving winter survivorship. Feeding stations, however, have also increased the risk of catastrophic mortality if a disease epidemic were to strike when the cranes were concentrated there. Second, installation of conspicuous markers on utility lines has reduced the rate of mortality from collisions. Prior to marking, 50-70% of Red-crowned Crane deaths were due to utility line collisions. Since markers were added in the late 1970s, the death rate from collisions has dropped approximately 60% (Masatomi 1991, M. Yamaguchi pers. comm.).
China and Russia conduct periodic aerial surveys of Red-crowned Cranes during the breeding season, and Japan surveys breeding birds annually. Winter populations are counted annually in coastal Jiangsu (China) and Japan, and periodically in South Korea. North Korea also surveys wintering cranes, but it has been difficult to gain access to this information. Shibaev and Surmach (1994) report the results of an autumn migration survey conducted in Russia’s Primorye region in 1988.
Winter counts are the most reliable index of the population. Breeding season surveys record fewer Red-crowned Cranes than do winter counts. A simultaneous aerial survey conducted in Russia, China, and Japan during the 1984 breeding season counted one-third fewer cranes than did winter surveys conducted from 1979-1985 in the same areas (Masatomi 1985b). Masatomi et al. (1985), Shibaev (1985), and Smirenski et al. (1988) all reported areas that could not be completely covered in their respective spring censuses. The aerial survey in China was also incomplete (Fei D. pers. comm.). In addition to the one pair of cranes from the Hokkaido population known to summer in the Kuril Islands, the Hokkaido survey probably missed other individuals, since it recorded only 70% (in 1984) and 80% (in 1993) as many cranes as had been found on winter counts (Masatomi 1985b, Masatomi et al. in press a). The Russian survey found about 213 cranes, while intensive studies in the summer of 1986 found a breeding population of at least 350 Red-crowned Cranes (Andronov 1988, Ilyashenko 1988, Shibaev and Glushchenko 1988).
Extensive research on habitat, habitat loss, breeding biology, and wintering ecology of the Red-crowned Crane has been conducted since 1970. Many of these studies are cited in other portions of this account. Japanese researchers (e.g., Masatomi 1970-1994, Akiyama 1981, Kitagawa 1982) have led the way, but since 1980 Chinese, Korean, and Russian scientists have expanded research on many aspects of the species’ distribution, biology, and ecology (e.g., Smirenski 1980, Winter 1981, Andronov 1988, Li and Feng 1985, Chong 1988, Ilyashenko 1988, Smirenski et al. 1988, Zhou 1988, Ma and Li 1991). Banding studies have been carried out in China (Xu et al. 1995). Satellite radiotelemetry of Red-crowned Cranes migrating to and from Russia is now in progress by Dr. Hiroyoshi Higuchi and his colleagues (e.g. Higuchi et al. 1994a, 1994b, 1995). Much of the information from these recent studies has been published in the Proceedings of the 1983 International Crane Workshop (1987), The Palearctic Cranes (1988), the Proceedings of the 1987 International Crane Workshop (1991), The Future of Cranes and Wetlands (1994), and Cranes and Storks of the Amur Basin (1995).
Population and Habitat Viability Analysis
A crane PHVA that included significant preliminary work on Red-crowned Cranes was conducted in Calgary, Canada, in 1992, by the IUCN/SSC Conservation Breeding Specialist Group with the assistance of ICF (Mirande et al. in press a). A subsequent meeting focussing on Red-crowned Cranes was held in Shenyang, China in March 1993. Meeting participants were able to determine more accurately the parameters of the captive and wild populations, and offered a series of observations, conclusions, and recommendations, including the following (Mirande et al. in press a):
The Wild Bird Society of Japan (WBSJ), ICF, the Socio-Ecological Union (SEU), other conservation groups, and university researchers have joined forces in efforts to conserve the Red-crowned Crane. SEU has established the 5,200 ha Muraviovka Reserve in Russia with funding support help from WBSJ and a Japanese company, POP Group International. SEU is also helping farmers to improve crop production efficiency, so that adequate amounts of food can be produced on much smaller amounts of land than under current methods. Many other examples of such cooperative measures can be found in the examples and publications cited in this account.
Education and Training
The Hokkaido government has sponsored annual Red-crowned Crane winter counts by school children since 1952 (Kushiro ECRPT 1993). The feeding stations there allow residents to observe the cranes closely. The Akan International Crane Center opened in Hokkaido in 1996. The Center, a cooperative venture of the Tancho Sanctuary in Tsurui, the Tancho Natural Park in Kushiro, and the Tancho Protection and Propagation Center of the Kushiro Zoo, is devoted to education and research on cranes.
The Zhalong and Yancheng Nature Reserves in China provide educational opportunities for the public through visitor centers. Visitors can observe captive cranes at Zhalong or observe cranes at a feeding station at Yancheng. The SEU and ICF are collaborating on teacher exchanges and other education projects in Russia. Recent international conferences, especially the Amur (1992) and Tokyo (1993) meetings, and those organized by the Rowe Sanctuary in Nebraska, have linked crane conservationists together to promote conservation in a variety of ways.
Captive Propagation and Reintroduction
Red-crowned Cranes have been maintained in captivity for centuries and are known to have bred in captivity by 1861 (Johnsgard 1983). In general, they readily breed under captive conditions and have a relatively high rate of survivorship (Belterman and King 1993). The species can maintain a stable captive population with a low reproductive rate (Swengel 1985), thus allowing managers to increase the genetic diversity of the captive population by encouraging equal genetic representation among founders.
The first international studbook was published in Japan in 1972. The draft 31 December 1992 studbook lists 747 birds in 158 institutions (Komiya 1994). Regional studbooks are now maintained in North America, China, Europe, and the United Kingdom. Although the species is being bred at many facilities, the Shenyang Zoo has emerged as the largest producer, with up to 20 chicks fledged per year, beginning in 1991.
In the past, founder representation within the captive population was highly skewed. As a result, genetic diversity within the European, Japanese, and North American captive populations has been low relative to their population sizes. A number of zoos in Europe, Japan, and the USA have exchanged individuals to improve genetic management of the species, but others are still inbreeding the birds. Since 1990 Chinese zoos have accelerated their domestic and international Red-crowned Crane exchanges, helping to increase genetic diversity in captive facilities around the world.
Reintroduction of Red-crowned Cranes has taken place on a limited basis at three natural breeding sites. At Kushiro, Zhalong, and Khinganski, cranes have been released from nearby captive breeding facilities; at Khinganski, cranes from North American captive breeding facilities were also released. The Tancho Natural Park in Hokkaido was established with five male cranes in 1958 (Masatomi 1981b). These males attracted wild females and the resulting park-bred juvenile cranes were allowed to fly out of the pens to the wild. At least 16 cranes, all of them chicks produced at the park, were released to the wild from 1973-1991 (Asakura and Ito 1982, Kushiro ECRPT 1993).
The Zhalong Nature Reserve in China has a crane breeding center and has released captive-bred Red-crowned Cranes in nearby marshes. About 20 were released in 1985-1986 (Xu J. et al. 1991). Some of these formed semi-wild breeding pairs, while others bred with wild cranes. The staff at Zhalong removed some of the early clutches from nests to increase egg production and to raise additional chicks in captivity (Xu et al. 1986b, Xu J. et al. 1991). In this way the center was able to raise more chicks for release while allowing wild and semi-wild pairs to continue breeding (Xu J. et al. 1991). In recent years five of the pairs have nested in the wild and returned in the autumn with their chicks to spend the winter near the captive cranes. In spring the juveniles leave the parents and join the wild cranes. As of 1994, 29 cranes have joined the wild flock in this way.
The Khinganski Reserve in eastern Russia began experimental releases of young Red-crowned Cranes in 1989 with the hope that released cranes would breed in areas near human settlements that appeared suitable but had no breeding pairs. Some cranes have become established in the wild. This study is still in progress (R. Andronova pers. comm.).
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International Agreements and Cooperation
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