Northern Prairie Wildlife Research Center
Subjects:
Summary
Subspecies/populations
Population Numbers and Trends
Conservation Status
Historic and Present Distribution
Distribution by Country
Habitat and Ecology
Principal Threats
Current Conservation Measures
Priority Conservation Measures
Summary
The Blue Crane, the national bird of South Africa, is still abundant in parts
of its historic range, but has experienced significant declines in many areas
over the last twenty years. Its distribution is the most restricted of the fifteen
crane species. It is endemic to southern Africa, with the vast majority of the
population occurring in eastern and southern South Africa. A small disjunct population
occurs in the Etosha Pan of northern Namibia, while breeding pairs are occasionally
found in five other countries. As recently as 1980, there was little concern about
the Blue Crane from a conservation standpoint. Since then, however, the species
has largely disappeared from the Transkei region, Lesotho, and Swaziland. In other
areas, including eastern Cape Province, Natal, northern Orange Free State, and
Transvaal, populations have declined by as much as 90%1.
The total population is estimated at 21,000 and is declining. Due to its rapid
decline, the species is classified Critically Endangered under the revised IUCN
Red List Categories. The Namibian population, because of its small size, is also
Critically Endangered.
The Blue Crane is primarily a bird of dry, upland grasslands. In South Africa, the species occurs in the grassland, Karoo, and fynbos biomes. Blue Cranes use natural grass- and sedge-dominated habitats in these biomes for both nesting and feeding, but will roost in wetlands if available. Preferred nesting sites are secluded grasslands in higher elevations, although they also nest in wetlands. In agricultural areas (especially converted farms in the fynbos region), they nest in pastures, fallow fields, and crop fields. Blue Cranes migrate locally across elevation gradients, spending the breeding season in higher elevation grasslands and moving to lower elevations for the fall and winter. Flocking occurs year-round, but intensifies in the winter.
Intentional and unintentional poisoning, afforestation of South Africa’s grasslands, and the impacts of growing human population pressure constitute the most significant threats to the Blue Crane. As these threats have taken their toll, conservation efforts have accelerated. These measures include: stricter legal protection for the species; local and national surveys of the population; expanded research on the species’ biology, ecology, and conservation status; increased attention to habitat management, especially on private lands; the emergence and active involvement of non-governmental organizations in Blue Crane conservation programs; and the development of new education programs focussing on the status and needs of the species.
Priority conservation measures for the future include: stronger enforcement of existing conservation laws; transfer of the species to CITES Appendix I; development of a coordinated plan to halt the poisoning of cranes; identification and protection of critical habitat, especially traditional wintering grounds; adoption of habitat management programs on farms and other private lands; requirements for impact assessments of proposed timber plantation projects; expanded surveys and monitoring programs throughout the species range; further research on population dynamics, demographics, seasonal movements, breeding habitat requirements, and the threats posed by poisoning and commercial afforestation; and development of educational programs specifically directed toward private landowners, farm laborers, and students.
1See note 1 in the Grey Crowned Crane species account regrding the political realignment of the South African provinces.
| Population | Number | Trend | Source |
| Southern | approx. 21,000 | Declining | Allan 1993 |
| Namibia | <100 | Stable | Hines in press |
| Total | approx. 21,000 | Declining | |
Long-term, range-wide data on the size and trend of the population are lacking. Recent population estimates have ranged between 10,000 and 23,000. The current estimate is based on Allan’s (1993) study of Blue Crane distribution and abundance. Significant local declines have been reliably reported from many areas, mostly in the grassland portion of the species’ range. Declines have been documented in Natal, Transvaal, and other areas where the species was formerly common, and where the species’ natural grassland habitats are likely to remain at risk (see Allan 1993, Urban in press). In the semi-desert habitats of the Karoo and in the agricultural fields of southwest Cape Province, the population is stable or increasing.
| Species | |
| IUCN category | Critically Endangered, under criteria A1a,c,e |
| CITES | Appendix II |
| Populations | |
| Southern | Critically Endangered, under criteria A1a,c,e |
| Namibia | Critically Endangered, under criterion D |
The Blue Crane is endemic to southern Africa, with more than 99% of the population occurring within South Africa (Allan 1993). While locally abundant in limited parts of its range, it is now rare in most areas. Until recently, it was abundant in the uplands of eastern Cape Province, northern Orange Free State, southern and eastern Transvaal, and western Natal (Urban 1987, Johnson 1992a, Vernon et al. 1992, Allan 1993). A small (<100) disjunct breeding population exists in northern Namibia in and around Etosha Pan. The species occurs as an occasional vagrant in northwestern Cape Province, northern Transvaal, Lesotho, and Botswana (Allan 1993, Morris 1987). Swaziland, on the eastern edge of the species’ range, has a small breeding population (Brown 1992, Hines in press). Several reports of its occurrence in Zimbabwe have been published, and occasional birds may wander into Mozambique, but these observations have not been confirmed.
As recently as 1980, the Blue Crane population was considered to be “healthy throughout South and Southwest Africa” and “nowhere endangered” (Van Ee 1981). Although the species is still found throughout much of its historic range, it has experienced significant and rapid local declines over the last twenty years. The species range has retracted from the Transkei region (where it may never have been very abundant), most of Swaziland, and the lower-lying portions of Lesotho. In some areas, populations may have declined by as much as 90% (Allan 1994, Urban in press). Losses are most evident in the grassland strongholds of eastern Cape Province, western Transvaal, northern Orange Free State, Lesotho, Transkei, and Natal (Vernon et al. 1992, Tarboton 1992a, Stretton 1992, Allan 1994, Urban in press).
Due to declines in the central part of the species’ historic range, the South African population may now be divided in two, with one portion of the population centered in southern Transvaal, Natal, and northern Orange Free State, and the other in southern and eastern Cape Province (Allan 1994). However, the species appears to be stable in South Africa’s Karoo regions, and is thriving in the fynbos (where it is a relatively recent colonizer of agricultural areas) (Allan 1992, 1993). In recent years, the Namibian population has held steady at approximately 80 birds (Brown 1992, Hines in press).
| Botswana | r (occasional) |
| Mozambique | r (occasional) |
| Namibia | r |
| South Africa | R |
| Swaziland | r |
| Zimbabwe | r (occasional) |
| R = Resident (population > 1000) | |
| r = Resident (population < 1000) | |
The Blue Crane, like the Demoiselle Crane, is a bird of dry grasslands and other upland habitats. In South Africa, it is largely restricted to three biomes—the grasslands, the semi-desert Karoo, and the fynbos (the botanically diverse region of western and southern Cape Province). Within the grasslands, the species is more abundant and more evenly distributed in the eastern “sour” grasslands (where natural grazing of small livestock is the predominant land use) than in the central and western grasslands (where crop farming is widespread). In the arid Karoo, the species is found in areas where perennial grasslands are dominant over the more typical dwarf shrublands of the region. In the fynbos, the species is restricted almost exclusively to intensively cultivated habitats (mainly cereal crops and small livestock farming areas), and is largely absent from areas of natural vegetation. Allan (1993) notes that the Blue Crane has benefitted from the advent of widespread cereal farming and the extirpation and control of predators in the region. Etosha Pan, where Namibia’s disjunct population is found, is a relatively limited (1400 km2) area of grassy plains and dwarf shrub savannah distinct from the surrounding woodlands of the region. The occasional sightings of the species in other parts of southern Africa have generally occurred in similarly isolated grassland habitats.
Habitat use varies among the different regions used by the cranes according to the time of the year and food availability (Allan 1993, 1994). Principal food items include the seeds of sedges and grasses, waste grains (mainly wheat, barley, and maize), insects, and small vertebrates. Where shallow wetlands (pans, reservoir edges, etc.) are available, Blue Cranes will roost in them at night (Allan 1993). In the southern Cape, Aucamp (in press) found an average density of .57 breeding pairs per km2 of suitable habitat.
Blue Cranes use natural grass- and sedge-dominated habitats for both nesting and feeding. Blue Cranes nest in the summer (generally from late September to February). Preferred nesting sites are secluded grasslands in higher elevations, where eggs are laid amid the grass or on bare ground. The vegetation at such sites tends to be relatively thick and short. Occasionally Blue Cranes breed in or near wetlands, building platform nests of reeds and other aquatic plants (Allan 1994, Aucamp in press). In agricultural areas, they nest in pastures, in fallow fields, and in crop fields as stubble becomes available after harvest (Allan 1993, Aucamp in press). Usually two eggs are laid. The incubation period is 30-33 days. The fledging period varies from 3-5 months (Schoeman 1994).
Blue Cranes have long been known to engage in seasonal movements within South Africa, but research involving the pattern of movements has been limited. Existing records indicate that Blue Cranes migrate locally across elevation gradients, spending the summer breeding season (October-March) in higher elevation grasslands and moving with chicks to lower elevations for the fall and winter (this pattern is best documented in Natal). Recent studies have suggested a general pattern of movement into the Karoo biome during the winter (Vernon et al. 1992, Allan 1993). However, Allan (1993) concludes that “the Blue Crane is a partial migrant and... some birds are found throughout its South Africa range throughout the year.” Flocking can occur year-round, but intensifies in the winter, when groups of several hundred birds form (Vernon et al. 1992, Allan 1993).
Poisoning of cranes in southern Africa can take three forms: it can be intentional and aimed at killing cranes that cause crop damage; it can be inadvertent and aimed at killing other species that cause crop damage; or it can occur during the application of pesticides to crop fields (Filmer and Holthausen 1992; Johnson 1992b; Allan 1993, 1994). Intentional poisoning of cranes is illegal in South Africa, but has occurred increasingly in the last fifteen years. Tarboton (1992) notes that the new types of poisons being used have made it easier to kill cranes, both deliberately and accidentally.
Most reports of poisoning of Blue Cranes have come from southwestern Cape Province. This probably reflects the greater effort expended in finding and documenting episodes of poisoning in this region rather than a greater concentration of such incidents. It is unclear why the species has apparently declined in the face of poisoning in the grasslands but not in the intensively cropped areas of southwestern Cape Province. Precise details involving incidents of poisoning have often been lacking in the published reports. The best evidence indicates that poisoning occurs disproportionately in the late winter-early spring (August-October). This is the period when crops are planted or are germinating and when livestock receive supplementary feed (upon which cranes forage). In addition, the cranes are still in their large winter flocks at this time. Thus, they are more likely to congregate in large numbers at feeding sites and are more vulnerable to mass mortality through poisoning.
The other major threat facing the Blue Crane is the commercial afforestation of South Africa’s natural grasslands (Macdonald 1989, Johnson 1992a, Stretton 1992, Tarboton 1992). In most cases, grasslands have been converted to pine and eucalyptus plantations for eventual production of pulp and timber. Such plantings deprive Blue Cranes of the dry, open conditions they require, especially for breeding. In addition, afforestation alters hydrological processes within the affected watersheds by reducing the amount of run-off and groundwater flow, leading to the desiccation of wetlands. Approximately 1.2 million hectares have already been afforested in South Africa, and existing plans call for this area to double (W. Tarboton pers. comm.). The impact has been greatest in the eastern sourveld, and in the future is likely to intensify in eastern Transvaal, Natal, and eastern Cape Province.
Blue Cranes are also affected by development pressures and high human population density, which have combined to exacerbate the incidence of intensive livestock grazing, disturbance, active persecution, and loss of habitat to agricultural expansion (both crop farming and grazing). This has led to the extirpation or heavy reduction in Blue Crane numbers in several areas, including Swaziland, Lesotho, and Transkei (Allan 1993). The development of irrigated agriculture in the Karoo as a consequence of the construction of the Orange-Fish River Canal may pose a long-term threat to the population in northeastern Cape Province by increasing the level of crop predation and subsequent poisoning (Stretton 1992, Allan 1994).
Other anthropogenic threats include: urban and residential expansion; mining; collisions with utility lines and fences; spraying of wetlands with poisons to destroy passerine seedeaters (primarily Quelea quelea); predation of eggs and chicks by domestic dogs; the drowning of chicks in water troughs; and other forms of human activity and disturbance (Geldenhuys 1984; Filmer and Holtshausen 1992; Johnson 1992a, 1992b, 1992c; Scott 1992; Vernon et al. 1992; McCann and Wilkins 1994). Some trade in Blue Cranes may be occurring. Although it is illegal to take cranes from the wild in South Africa, chicks are sometimes taken into captivity for pets. A survey conducted in 1985 revealed that at least 439 were being kept in private gardens under permit (Allan 1985). Many more are illegally held.
Legal and Cultural Protection
The Blue Crane is the national bird of the Republic of South Africa. The capture and export of Blue Cranes has been forbidden in South Africa since the 1970s, and existing laws stipulate that cranes cannot be poisoned, shot, collected, or otherwise disturbed without a permit. However, this legal protection has been largely superficial. Legislation to protect the Blue Crane and other crane species in South Africa has recently been strengthened, and penalties for violations increased. Cape Nature Conservation hopes to adopt new policies to discourage the illegal keeping of cranes in captivity, but these have not yet been officially approved (A. Scott pers. comm.).
A Conservation Program for the Blue Crane in the Overberg
In 1993, the Overberg Crane Group developed and published A Conservation Programme for the Blue Crane in the Overberg (A. Scott 1993). This comprehensive program emerged from a Blue Crane workshop, involving a broad range of representatives from the local community, that took place in July 1992. The goals of the program are to assess the status of the Blue Crane in the Overberg region, to address problems that cranes have caused for farmers, and to expand conservation measures for the Blue Crane in the region. To meet these goals, nine specific conservation projects were outlined, and coordinators assigned to monitor progress and provide feedback to the Overberg Crane Group. Officials of the Cape Nature Conservation contribute to the implementation of these projects as part of their assigned duties, while volunteers from the farming community, universities, and other institutions also participate. The Overberg Program has met with considerable success to date and provides a useful model for conservationists in other portions of the species’ range (Jones 1994, Scott and Scott in press).
Protected Areas
Siegfried (1992) reports that Blue Cranes have been recorded in at least 75 nature reserves in South Africa, though not necessarily as a breeding (or even regularly occurring) species. Allan (1994a) notes that only a small fraction of the total population—less than 200 pairs—breed in nature reserves. Johnson and Barnes (1986) stress the inadequacy of relying on reserves for conservation of the species since too few of the cranes occur in too few protected areas; moreover, those that do use protected areas are not residents, but frequently move onto adjacent farms where they are vulnerable to the threats present in agricultural lands. In some cases, however, protected areas may provide a last line of defense for threatened populations. Allan (1993) noted that the total remaining breeding population of 12 Blue Cranes in Swaziland was restricted to the Malalotja Nature Reserve. Similarly, the entire Namibian population is found within Etosha National Park (Brown 1992).
Habitat Protection and Management
Because only a relatively small proportion of the total population of Blue Cranes live within nature reserves or national parks, and even these areas are not large enough to meet all their habitat requirements, the long-term conservation of the species rests almost entirely with private landowners. In South Africa, this aspect of crane conservation has received increased attention in recent years (Johnson 1992c, A. Scott 1993, Allan 1994). Johnson (1992c) notes that the land-use practices that favor cranes are now fairly well understood (e.g., appropriate fallow periods, planting of lure crops, baiting roost sites with waste grain), and that landowners may easily be able to accommodate cranes without disruption of farming practices. Much of the emphasis until now has been on defining and communicating habitat management requirements. To encourage the implementation of these measures, attention is now shifting toward the development of demonstration areas, increased farmer participation, and adoption of economic and policy incentives.
Surveys/Censuses/Monitoring
Counts and surveys of Blue Cranes have been conducted in various portions of the species’ range. Siegfried (1985) reported on an extensive series of road counts of Blue (and Grey Crowned) Cranes undertaken in Cape Province in 1965-66. Vernon et al. (1992) presented data from similar counts of the same two species in the eastern Cape Province from 1977 to 1987. Filmer and Holtshausen (1992) reported the results of a census of all three southern African crane species conducted in 1985-86. An aerial census of the Natal midlands was conducted in 1994 in a cooperative effort of Eskom, the Endangered Wildlife Trust, and the Natal Parks Board (see below) (McCann and Wilkins 1994). Blue Cranes have also been counted during the African Waterfowl Census conducted by the IWRB (Taylor and Rose 1994, Davies in press).
Allan (1995) reports the results of counts carried out by the Cape Bird Club in 1993 and 1994 in southern Cape Province. The Namibian population is counted during aerial surveys of Etosha National Park. Young birds in this population have also been banded (Brown 1992). Allan (1993) combined data from bird atlas reports, road counts, line transect counts, and aerial censuses to determine the abundance and distribution of Blue Cranes throughout its range. This study represents not only the most extensive work on the Blue Crane, but the first application of such techniques to the study of any species of crane throughout its entire range.
Research
Until relatively recently the Blue Crane was poorly studied (at least in part because it was presumed to be of little conservation concern). Walkinshaw (1963) studied its breeding habits in Natal, while Van Ee (1966) reported on its breeding behavior in captivity. Two avian handbooks covering the area of distribution (Urban et al. 1986, Maclean 1993) contain brief summaries of the biology of the Blue Crane.
In the last ten years, research has expanded significantly. Several assessments of the status of populations in various parts of the species’ range have been published in recent years (Geldenhuys 1984, Siegfried 1985, Johnson and Barnes 1986, Tarboton et al. 1987b, Allan 1992, Brown 1992, Johnson 1992a, Vernon et al. 1992). Filmer and Holtshausen (1992) report on the distribution, abundance, habitat, breeding, and conservation status of the Blue Crane based on data derived from the Southern African crane census. Several regional bird atlases include distribution maps for the species in various parts of South Africa. Allan (1993) provides a comprehensive study of the species’ biology, ecology, distribution, and conservation status.
Since 1994, Eskom and the Endangered Wildlife Trust have collaborated in a research program involving the Wattled, Blue, and Southern Crowned Crane in the Natal midlands. As part of this program, satellite tracking studies are to be undertaken to enhance understanding of the local and seasonal movements of Blue Cranes. These studies are expected to contribute to the development of a management plan for these three species (McGann and Wilkins 1994).
Non-governmental Organizations
Several non-governmental organizations have been instrumental in stimulating interest in Blue Cranes and promoting conservation measures in South Africa. The Southern African Crane Foundation (SACF) (P.O. Box 74, Mooi River 3300, Natal, RSA) was established in 1988, and works to conserve all three of southern Africa’s crane species. SACF now serves as an umbrella organization for coordinating the activities of several working groups and other organizations devoted to crane conservation in the region: the Natal Crane Working Group (Natal Parks Board, P.O. Box 662, Pietermarlisburg, Natal, RSA); the Overberg Crane Group (P.O. Box 1, Voëlklip 7203, RSA); the Highlands Crane Group of the Endangered Wildlife Trust (Private Bag X11, Parkview 2122, RSA); and the Wakkerstroom Natural Heritage Association (P.O. Box 223, Wakkerstrom 2480, RSA). The Southern African Ornithological Society (P.O. Box 87234, Houghton 2041, Johannesburg, RSA) is dedicated to the conservation of all the indigenous birds of the region, and supported the formation of the SACF. The Endangered Wildlife Trust is concerned with the conservation of biodiversity in general in southern and central Africa. EWT has devoted special attention to working with farmers to provide stronger protection for cranes and their habitats (Rodwell 1994). Allan (1994a) provides further information on these organizations and their activities.
Education and Training
Educational programs involving Blue Cranes and their habitat have been carried out mainly through the NGOs. An interpretation and education center is being developed at Hlatikulu, Natal under the auspices of the SACF. Two of the projects outlined in the Blue Crane conservation program of the Overberg Crane Group involve education and the dissemination of information among students, landowners, farm workers, decision-makers, and the general public (A. Scott 1993). In particular, the Overberg Crane Group has begun to work closely with farmers to expand awareness of crane behavior and appropriate adaptation of farming operations. A Crane Education Forum was established in 1993 to develop and distribute community-based educational materials on crane conservation (for information contact Christine Lambrechts, 97 Westcliff Dr., Hermanus 7200, RSA). The Forum grew out of the 1993 African Crane and Wetlands Training Workshop and will focus on promoting the responsible use of agricultural chemicals among farm workers (A. Scott pers. comm.). In 1994, the Endangered Wildlife Trust published a informational booklet, Cranes and Farmers (Allan 1994), that is now being widely distributed.
Captive Propagation and Reintroduction
The GCAR for cranes identified 976 Blue Cranes in captivity worldwide as of 1993 (Mirande et al. in press a). This figure does not include an additional, unknown number of birds held in the private sector (see Allan 1985, Schoeman 1994). An African regional studbook for the species has been prepared in South Africa (Schoeman 1994), and regional studbooks are being developed in North America and the United Kingdom. The species breeds reasonably well in captivity. It is represented in adequate numbers within South Africa, and so a global breeding program is not required.
At present, no reintroduction program has been undertaken, and other conservation needs are of higher priority. Reintroduction has been discussed as a conservation strategy for portions of the species’ historic range where it no longer occurs. However, if the species is protected and its habitat restored, the population can be expected to expand rapidly in the wild. This may already be occurring, for example, in portions of Natal. The Blue Crane conservation program of the Overberg Crane Group has recommended that injured and permanently disabled birds be used in captive breeding programs (A. Scott 1993). Given the high level of interest in the species for educational purposes, such programs may provide conservation benefits while minimizing impacts on wild populations.
Legal and Cultural Protection
The threat posed by the poisoning of Blue Cranes is serious and demands a coordinated program of response. As such a program is developed, the following measures should receive high priority.