Northern Prairie Wildlife Research Center
Population Numbers and Trends
Historic and Present Distribution
Distribution by Country
Habitat and Ecology
Current Conservation Measures
Priority Conservation Measures
The Grey Crowned Crane is the most abundant of the resident African cranes.
Although precise population numbers are not available, recent estimates place
the total population at 85,000-95,000. Two subspecies are recognized. B. r.
gibbericeps (the East African Crowned Crane) comprises the majority of the
total population. It occurs in East Africa from northern Uganda and Kenya south
to Zimbabwe, Botswana, and Namibia. B. r. regulorum (the South African
Crowned Crane) is found in Zimbabwe and South Africa. Although the species remains
relatively abundant, the total estimated population has declined from more than
100,000 over the last decade. It no longer occurs in certain portions of its historic
range (especially the drier areas). The species is classified as Vulnerable under
the revised IUCN Red List Categories. B. r. regulorum is classified Endangered,
and B. r. gibbericeps Vulnerable.
Grey Crowned Cranes use mixed wetland-grassland habitats for nesting and foraging, and along with Black Crowned Cranes are the only cranes able to roost in trees. The species’ generalist feeding strategy has allowed it to adjust to human settlement and activity; most populations in East Africa now live in human-modified habitats. The abundance and distribution of food and nest sites are the key ecological factors determining the size of the home range. These, in turn, are largely influenced by local rainfall regimes. Grey Crowned Cranes are non-migratory, but undertake local and seasonal movements in response to changing moisture levels and food availability.
Although Grey Crowned Cranes and people have long coexisted, the decline in the species’ population over the last decade reflects widespread threats to their habitats as a result of rapid human population growth, drought-related changes in land use, intensified agricultural practices, and other factors. Loss and deterioration of wetland breeding habitat constitute the most significant threats to the species. Other problems include increased use of agricultural pesticides, declines in the fallowing of croplands, high rates of wetland sedimentation due to deforestation, and altered flooding regimes due to dam construction. The capturing of Grey Crowned Cranes for domestication and for export is also a serious threat.
In many areas, the Grey Crowned Crane is considered a sacred bird, and its cultural significance has provided a high level of local protection. No range-wide surveys of the species have been undertaken, but crane counts and localized surveys have been undertaken intermittently in a number of countries. In recent years, field studies have begun to provide basic biological information on the species, although the knowledge base remains relatively limited compared to other crane species. The increasing number and effectiveness of protected areas, especially in East Africa, has benefitted the species. However, since most Grey Crowned Cranes nest and forage outside protected areas, the overriding conservation challenge has been to develop sustainable alternatives to the overexploitation of non-reserved wetlands. This goal has stimulated a number of community-based wetland conservation projects as well as the development of national-level crane and wetland conservation plans. Non-governmental organizations have often played a key role in these efforts.
Priority conservation measures for the species include: transfer of the species to CITES Appendix I; strengthened laws to restrict trade and protect wild cranes; expansion of community-based wetland conservation programs; designation of additional reserves to protect key breeding areas; development and implementation of national crane and wetland conservation plans, and of more specific management programs for key breeding habitats outside protected areas; organization of national-level crane counts; establishment of long-term monitoring programs; research on the basic biology and ecology of the species, critical habitat, local and regional movements, and the incidence of crop damage; and development of broad-based public awareness programs as well as more specialized educational programs.
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|East African Crowned Crane||B. r. gibbericeps|
|South African Crowned Crane||B. r. regulorum|
The subspecies are most easily distinguished by their facial features: B. r. gibbericeps has a larger area of bare red skin above the white cheek patch than does B. r. regulorum.
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|B. r. gibbericeps||75,000-85,000||Declining||Urban in press,
N. and C. Gichuki
|B. r. regulorum||approx. 10,000||Unknown;
|Urban in press,
N. and C. Gichuki
D. Allan, pers. comm.
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|IUCN category||Vulnerable, under criteria
|East African (B. r. gibbericeps)||Vulnerable, under criteria
|South African (B. r. regulorum)||Endangered, under criteria
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The range of the Grey Crowned Crane in eastern and southern Africa stretches from eastern Zaire, Uganda, and Kenya to southeastern South Africa (Walkinshaw 1964). Grey Crowned Cranes are non-migratory, but undertake variable local and seasonal movements in response to the abundance and distribution of food and nest sites (Pomeroy 1980, 1987). The range of B. r. gibbericeps meets that of B. pavonina in northern Uganda and northwest Kenya (although further field studies are needed to verify the extent of B. pavonina’s occurrence in this region). The species’ range extends south to Zimbabwe and Botswana, and west along the Okavango River into Namibia. The species is most abundant (~60,000-70,000 birds) in Uganda, Kenya, and Tanzania (N. and C. Gichuki pers. comm.). B. r. regulorum occurs in Angola and Zimbabwe, and in South Africa to as far west as East London (Allan 1994, D. Johnson pers. comm.). A gap of several hundred kilometers separates the populations of B. r. regulorum in Zimbabwe and those in South Africa.
The distribution of Grey Crowned Cranes seems to have changed little through most of this century, and the species remains relatively abundant (Pomeroy 1987). Between 1985 and 1994, however, the total estimated population declined by approximately 15% (Urban in press). This trend is based on country-level estimates and is corroborated by recent surveys conducted in Kenya, Uganda, and South Africa (Urban and Gichuki 1988, Johnson 1992a, Urban in press). Reductions in the species’ range have been reported in Namibia, South Africa, Namibia, and Zambia (Brown 1992, Tarboton 1992a, Allan 1994, Katenekwa in press).
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|Botswana||B. r. regulorum||r|
|Burundi||B. r. gibbericeps  ||r|
|Kenya||B. r. gibbericeps||R|
|Namibia||B. r. regulorum||r|
|Rwanda||B. r. gibbericeps||r|
|South Africa||B. r. regulorum||R|
|Tanzania||B. r. gibbericeps||R|
|Uganda||B. r. gibbericeps||R|
|Zaire||B. r. gibbericeps||R|
|Zimbabwe||B. r. regulorum||R|
|R = Resident (population > 1000)|
|r = Resident (population < 1000)|
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Grey Crowned Cranes require mixed wetland-grassland habitats. They typically nest within or on the edges of wetlands while foraging in wetlands, nearby grasslands, and croplands. Nesting usually occurs in areas where wetland vegetation is of sufficient height to conceal the cranes on their nests. Their preferred foraging habitat consists of expanses of short- to medium-height open grasslands adjacent to wetlands. There they feed on the tips of grasses, seeds, insects and other invertebrates, and small vertebrates. They also forage in croplands for groundnuts, soybeans, maize, millet, and other items (Johnsgard 1983, Pomeroy 1980). Both the Grey and Black Crowned Cranes may roost in water or perch in trees (or on utility line posts). While rearing chicks, adult birds will sometimes hide their young in the wetland in the evening, and then fly to roost in trees. Thus, while Grey Crowned Cranes may breed in wetlands as small as 1.4 ha, the availability of upland feeding and roosting areas may determine breeding success as much as the availability of wetlands (Gichuki 1993).
The Grey Crowned Crane’s generalist feeding strategy has allowed the species to adapt to human settlement. Most crane populations in East Africa now live in human-modified environments (Pomeroy 1987). They are commonly found in a variety of agricultural land types (pastures, grasslands, cultivated croplands, and irrigated lands), with sizable flocks occurring on farms and ranches in Kenya and Uganda. They are generally not found on small holdings or among perennial crops (D. Pomeroy pers. comm.). They have adapted especially well to commercial farms with man-made wetlands (reservoir shallows, seeps, etc.). In South Africa, Grey Crowned Cranes use permanent and temporary marshes in both grassland and savanna areas (utilizing smaller wetlands than do Wattled Cranes), but are also found at dam sites, in croplands and fallow fields, and in irrigated areas (Filmer and Holtshausen 1992, Vernon et al. 1992).
The abundance and distribution of food and nest sites are the key ecological factors determining the size of the home range and the extent of local and seasonal movements in Grey Crowned Crane populations (Pomeroy 1987, Gichuki and Gichuki 1991, Gichuki 1993). In areas where food is abundant and suitable breeding sites available, home ranges are relatively small and local movements limited. Gichuki (pers. comm.) found an average breeding territory of 630 ha and an average home range of 2880 ha in Kenya, but noted that the ranges of individual birds varied with age, breeding condition, and season of the year. In drier regions (such as Namibia), local movements are more extensive (Brown 1992).
Seasonality plays a critical role in determining behavioral patterns through the course of the year (Pomeroy 1980, 1987). The breeding season of the species varies depending on the duration and intensity of local dry and wet seasons (Walkinshaw 1964). In drier portions of the species’ range, breeding peaks during the rainy season. In other areas the cranes breed over a longer period, and if they are unsuccessful in raising a chick they can renest as long as wetlands are sufficiently flooded (Konrad 1987a, Gichuki and Gichuki 1991, P. Mafabi pers. comm.). Although Grey Crowned Cranes are normally seen in pairs, flocks consisting of as many as 200 birds are frequent in some areas during the non-breeding (late dry/early wet) season (Pomeroy 1980, 1987; Mafabi 1991). Studying the species in Transvaal, South Africa, Tarboton (1992a) found that between one-third and one-half the population occurred in pairs during the breeding season, while less than 10% occurred in pairs in the winter months1.
Grey Crowned Crane are sexually mature at three (rarely two) years. The species has the largest average clutch size (2.5+) of any crane. Clutch size can vary with altitude. Nests consist of uprooted grasses and sedges piled and flattened into a circular platform. The incubation period is 28-31 days. The fledging period is variable, generally between 56-100 days.
1The four former provinces of the Republic of South Africa have been replaced by nine new provinces. Natal is now known as KwaZulu/Natal, and Orange Free State as Free State Province. The other provinces are: Northwest, Eastern Cape, Northern Cape, Northern Transvaal, Gauteng, and Mpumalanga (eastern Transvaal).
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Although the species remains abundant over much of its historic range, it faces widespread (and probably accelerating) threats to its habitat, particularly in the species’ stronghold in East Africa. Especially in Kenya and Rwanda, Grey Crowned Crane habitat has been lost or degraded due to rapid increases in the human population, rising demands for land for farming, and the pressures of economic development and drought (Archibald 1992a).
These general threats are reflected in several more specific habitat-related problems. Loss and deterioration of wetland breeding habitat, primarily due to drainage or overgrazing, are the most significant threats to the species. Most of the loss of breeding sites has resulted from drainage of wetlands for urban and agricultural expansion (Gitahi 1993, Mmari in press). Wetland reclamation is widespread in Uganda and Kenya, especially along the shores of Lake Victoria, and in areas where rice agriculture has expanded (Mafabi 1991, Zambia Crane Action Plan in press). The potential for accelerated wetland drainage in much of the species’ range remains high (Pomeroy 1987).
Livestock grazing practices have subtle impacts on habitat suitability. Sound pasture management and moderate grazing are essential to the maintenance of the supply of grass seeds used by cranes. Livestock also flush insects that are eaten by cranes, and deter domestic dogs and other potential predators (Gichuki 1993). In some areas, however, the increasing livestock population has resulted in the overgrazing of wetlands, reducing the amount of emergent vegetation. Nesting is inhibited as the vegetation cover is removed. In addition, heavy livestock grazing has been shown to disrupt foraging behavior (Mmari in press). As a result, cranes must increasingly use more marginal habitats, especially nesting habitats.
Although Farming has in the past sometimes improved conditions for Grey Crowned Cranes, recent changes in farming practices have begun to have detrimental impacts. Intensified agricultural land use has shortened (or entirely eliminated) fallow periods, when cranes may safely use wheat, young maize, and rice fields for foraging (Mafabi 1991). Heavy application of pesticides has been identified as a threat in many countries, including Uganda, Malawi, Zambia, Zimbabwe, and South Africa. Where cranes are abundant, crop damage has been reported (Katondo in press b, P. Mundy pers. comm.). This seems to be a problem especially when drought reduces food supplies for cranes. As a result, the incidence of shooting and intentional poisoning has increased from time to time in some portions of the species’ range (Urban and Gichuki 1991, Johnson 1992b, Gichuki 1993, Allan 1994, McGann and Wilkins 1994).
Longer-term environmental fluctuations may contribute to some of the recent changes in the species’ numbers and distribution. Populations are highly responsive to changes in precipitation levels, the numbers rising and the range expanding during wetter years. In drier years, grassland and wetland fires may take their toll. The apparent reduction in the population in the upper Okavango River in Namibia may be due in part to drought conditions and shifting climatic patterns (Brown 1992). In many parts of the range, groundwater extraction has increased due to drought and rising demands for water for domestic, agricultural, and industrial uses. This has lowered the water table in some regions (most notably in South Africa), affecting especially the smaller wetlands.
Grey Crowned Cranes are also threatened by egg-collecting, hunting, and live-trapping. Gichuki (1993) determined that hunting of the species for food was responsible for about 15% of total mortality in a western Kenya study area. Grey and Black Crowned Cranes have long been valued as ornamental birds in private collections and thus are highly attractive to traders (Pomeroy 1987). The cranes are frequently captured as chicks and taken into captivity, where most perish (N. Gichuki pers. comm.). Capture for domestication and for the export trade is most extensive in Kenya, Uganda, and Tanzania, and should be considered a serious threat (Mafabi 1991, Katondo in press a, Mirande et al. in press a).
Conservation of Grey Crowned Cranes is also hindered by the general lack of biological knowledge about the species, the low level of public awareness of their conservation needs, and the ineffectiveness of existing laws intended to protect the cranes.
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Legal and Cultural Protection
The degree of protection for the Grey Crowned Crane varies. It is legally (although not always effectively) protected in Kenya, Uganda, Zimbabwe, and South Africa (Morris 1987, Mafabi 1991, Johnson 1992b). In many areas, the species benefits from its special cultural significance. It is the national bird of Uganda, and is regarded as a sacred bird or important symbol in parts of Kenya, northern Namibia, Zambia, and other parts of its range. As a result, the species has done well in western and central Kenya despite high human population density (N. and C. Gichuki pers. comm.). Similarly, in the Transkei region of South Africa, the high regard in which the species is held has allowed it to thrive locally despite significant habitat deterioration. In some areas of Kenya, it is considered an inauspicious omen if Grey Crowned Cranes are found close to homes (C. Budde pers. comm.). However, this has apparently not led to persecution of cranes in these areas.
International Agreements and Cooperation
As of June 1995, Kenya, South Africa, Uganda, Zambia, and South Africa had signed and ratified the Ramsar Convention, while Tanzania and Namibia were advancing toward ratification.
Community Conservation Programs
Community-based wetland conservation programs have been most fully developed in Kenya. The Kaisagat Environmental Conservation Youth Group and the Kipsaina Wetland Conservation Organization provide successful models for this approach. By integrating a variety of conservation activities—soil and water conservation practices, gardening and fish farming, tree nurseries and afforestation—and providing networking and education opportunities, these programs have provided a foundation for sustainable resource use and development. Cranes have proven in these two instances to be an effective means of communicating the need for conservation and for stimulating action at the community level (N. Gichuki pers. comm., Wanjala in press).
Most Grey Crowned Cranes nest and forage outside of protected areas. However, many national parks and other protected areas in East Africa do provide protection for Grey Crowned Crane habitat (Pomeroy 1987). These include: Abijatta-Shala Lakes, Gambella, and Mago National Parks in Ethiopia; Saiwa Swamp and Amboseli National Parks in Kenya; Queen Elizabeth and Lake Mburo National Parks in Uganda; Akagera National Park in Rwanda; Nyika National Park and Rwaza Nature Reserve in Malawi; and South Luangwa, Lochinvar, and Blue Lagoon National Parks in Zambia. In South Africa, the Wakkerstrom Wetland Reserve and Crane Sanctuary, the Steenkampsburg Nature Reserve, and the Umvoti Vlei and Umgeni Vlei Nature Reserves are significant sites for Grey Crowned Cranes.
Habitat Protection and Management
Although habitat management has not usually been undertaken specifically for the Grey Crowned Crane, wetland conservation in general has been the subject of increased attention in eastern and southern Africa. Throughout the species’ range, the overriding habitat conservation challenge has been to improve the welfare of the rural people by devising sustainable alternatives to drainage and overgrazing of wetlands. This goal has been pursued at both the local and national level. In Kenya, for example, community-based wetland conservation projects have been developed with an emphasis on cranes and other wetland wildlife (see above).
Since the mid-1980s, several range countries, including Rwanda, Malawi, and Zambia, have developed national wetland management plans and programs, often with the assistance of the IUCN, the World Wide Fund for Nature, and other conservation organizations (see Jeffery et al. 1992). Most recently (in July 1994), the Ugandan government approved and adopted a national wetland policy, and enabling legislation is now being enacted (P. Mafabi pers. comm.). At the 1993 African Crane and Wetland Training Workshop in Maun, Botswana, 12 of the Grey Crowned Crane range countries prepared preliminary crane and wetland action plans (Beilfuss et al. in press).
Urban (in press) provides country-level estimates of Grey Crowned Crane populations based on information presented at the 1993 African Crane and Wetlands Training Workshop. No range-wide surveys of the species have been conducted. In the last decade, however, surveys have been undertaken intermittently in a number of range countries, including Kenya (Gitahi 1993), Uganda (Mafabi 1991), Namibia (Brown 1992), and South Africa (Johnson and Barnes 1986, Johnson 1992a, Filmer and Holtshausen 1992, Tarboton 1992a, Vernon et al. 1992, McCann and Wilkins 1994). In Kenya, local crane counts were organized in the late 1980s, but have not been conducted on a regular basis since 1990 (Hill 1988, Mafabi 1989, M. Hill pers. comm.). Grey-crowned Cranes have also been counted during the African Waterfowl Census conducted by the IWRB (Taylor and Rose 1994, Davies in press).
Although information on the biology and ecology of Grey Crowned Cranes remains relatively scarce, researchers have begun to fill in many of the knowledge gaps over the last two decades. Field studies have been undertaken at the regional level in East Africa by Pomeroy (1987), and at the national level in Kenya (Gichuki 1993), Tanzania (Frame 1982, Katondo in press a), Rwanda (Kanyawimba in press), Uganda (Pomeroy 1980, Mafabi 1991), Zambia (Konrad 1987a, Dodman in press, Katenekwa in press), and in Natal (Johnson 1992a), Transvaal (Tarboton 1992a), and eastern Cape Province (Vernon et al. 1992) in South Africa.
Several recent studies have focused on topics especially relevant to crane conservation efforts. Gichuki’s (1993) study of factors affecting the reproductive success of the Grey Crowned Crane in Kenya represents the most extensive field research undertaken on the species. Katondo (in press) studied the incidence of crop damage in irrigated rice fields in Tanzania. Mmari (in press) focused on the impact of livestock grazing on cranes in Tanzania. Much of this information may be found in the Proceedings of the First Southern African Crane Conference (1992) and the Proceedings of the 1993 African Crane and Wetland Training Workshop (in press). In South Africa, Eskom and the Endangered Wildlife Trust are now collaborating in a research program involving the Wattled, Blue, and Southern Crowned Crane in the Natal midlands. These studies are expected to contribute to the development of a management plan for these three species (McCann and Wilkins 1994).
Daut (1994) conducted an epidemiological survey of Inclusion Body Disease of Cranes (IBDC) among Grey Crowned Cranes at Saiwa Swamp National Park in Kenya and in several zoos in South Africa. There were no indications that the birds were infected with the disease. Vocal communication between parental cranes and their juveniles is the main focus of another study at the crane and wetland research center in Saiwa National Park in Kenya. This study provides a logical follow-up to studies carried out at the site since 1986 (N. Gichuki pers. comm.).
Conservation activities involving the Grey Crowned Crane have been coordinated and implemented through a number of NGOs, including: Crane Study Groups in Kenya and Uganda; the Wildlife Clubs of Kenya (WCK); the World Wide Fund for Nature (which has sponsored crane conservation work in Kenya and Uganda); and IUCN (which has supported the national wetland conservation program in Uganda). Non-governmental organizations (often in collaboration with national and international conservation organizations) have often played a key role in developing community-based conservation programs by facilitating the participation and involvement of the local population, and by monitoring progress to ensure their effectiveness.
ICF has helped to coordinate Grey Crowned Crane counts in Kenya (with the WCK) and in Uganda (with the Wildlife Clubs of Uganda), and has supported research, training, and information exchange among African crane biologists and conservationists. In South Africa, the Southern African Crane Foundation, the Southern African Ornithological Society, and the Highlands Crane Group of the Endangered Wildlife Trust have all supported work on the species (Allan 1994, McCann and Wilkins 1994, Rodwell 1994).
Education and Training
Because Grey Crowned Cranes are familiar to local people, held in high regard, and often found in heavily populated areas, they are unusually well suited for use in conservation education projects. Crane counts have proven to be particularly effective tools for stimulating local interest in wildlife protection and for involving students and others in projects involving conservation and sustainable development. The community-based conservation projects described above have emphasized education about cranes, wetlands, and sustainable use of wetlands and other natural resources. ICF has developed a curriculum involving cranes and wetlands for use in Uganda’s secondary schools that could be adapted to other countries (M. Hill pers. comm.).
Professional training opportunities involving crane and wetland conservation have expanded in recent years, particularly in connection with the 1993 African Crane and Wetland Training Workshop. ICF has provided training courses in environmental education and crane and wetland biology for biologists from Kenya, Uganda, Malawi, Zambia, and South Africa.
Captive Propagation and Reintroduction
The GCAR for cranes estimated that 1212 Grey Crowned Cranes were in captivity worldwide as of 1993 (Mirande et al. in press a). However, this figure does not include a substantial number of additional birds held in the private sector. Of the total identified in the GCAR, 389 were reported as B. r. gibbericeps, and 69 as B. p. regulorum; the remainder had no subspecies designation. No studbook has yet been developed for the species. The species breeds readily in captivity and a significant number have reproduced. Interbreeding between the two subspecies and with Black Crowned Cranes has occurred (Mirande et al. in press a). No reintroduction program has been undertaken for the species and none is recommended at present.
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The overriding need through much of the Grey Crowned Crane’s range is for conservation programs that promote crane and wetland protection along with improvements in local resource use practices. In order to promote such programs:
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