Species Information
BLUE CRANE (Anthropoides paradiseus)Red data Category : Vulnerable
Population : < 25 000 adults
Key habitats : Natural grassland, grassy karoo, agriculturally transformed Renosterveld
Main threats : Habitat loss, poisonings, powerline collisions, chicks removed from the wild
The Blue Crane is endemic to South Africa, has the most restricted global range of all crane species and is South Africa's National Bird. Due to it having such a restricted range and the fact that it has declined rapidly over large areas of its range during the last two decades, qualifies this species as Vulnerable. Direct poisoning of birds and the indirect loss of grassland breeding habitat has led to this species' reduction in population size.
Distribution
The Blue Crane is endemic to South Africa, with the only other small populations being located in Etosha Pans (northern Namibia) and the western parts of Swaziland (Brown 1992). While locally abundant in limited parts of its range, it is now rare in most parts. Its population may be divided into three, with one portion of the population centred in the Mpumalanga, N.E. Free State, and KwaZulu-Natal regions into the northern parts of the Eastern Cape. A second occurs in the central Karoo situated within the Northern Cape extending into the Karoo regions of the southern Free State and Eastern cape, and the last in the south Western Cape (Overberg / Swartland regions), where it is a relatively recent colonizer of agricultural areas (Allan 1993). The species range has diminished from the "old" Transkei region, and occurs as an occasional vagrant in Lesotho and Botswana (Allan 1993).
Figure 1 : Distribution of the Blue Crane according to the South African Bird Atlas Project (Harrison et al. 1997)
Population
Although this species is still found throughout much of its historic range, it has experienced significant and rapid local declines over the last twenty years. The most recent estimate puts the population at 21 000 individuals. A National Crane Census performed during 1998 (McCann 1998) revealed 19 919 Blue Cranes within South Africa, with the majority of these being found within the Karoo habitats and the agriculturally transformed renosterveld of the Western Cape. 10 650 of these are located in the Overberg / Swartland region of the Western Cape (53,5 % of South Africa's population), with other significant populations being found in the scrub Karoo of the Eastern Cape (3 300 centred on Graaff Reniet) and the grassy Karoo of the Northern Cape province (2650 centred on De Aar / Hanover). The remaining populations within Mpumalanga, the north eastern parts of the Free State, KwaZulu-Natal and the north Eastern Cape have shown marked declines, and in the areas of Mpumalanga and KwaZulu-Natal, declines of up to 80 % (Johnson 1992).
Ecology
The Blue Crane is a bird of dry short grasslands, and together with the Demoiselle Crane (A. virgo), the least dependent on wetland habitats for breeding. Within the grasslands, the species is more abundant and evenly distributed in the eastern "sour" grasslands (where natural grazing of livestock is the predominant land use). In the arid Karoo, the species is found in areas where perennial grasslands are dominant over the more typical scrub Karoo vegetation of the region. In the Western Cape, the species is restricted almost exclusively to intensively cultivated habitats (mainly cereal crops and small livestock farming). Blue Cranes are summer breeders, nesting from late September through to February. Preferred nesting sites are secluded open grasslands with full view around the nest for predator evasion. A clutch of 2 eggs is laid, generally in a shallow grassy depression or simply on the bare ground. Occasionally, Blue Cranes may nest in shallow seasonal wetlands, particularly where livestock numbers are high and risk of nest trampling is increased. In agricultural areas, they nest in pastures, in fallow fields and in crop fields as stubble becomes available after harvest. The Blue Crane is termed a partial migrant, gathering in large flocks during the winter months having moved out of their breeding territories. The understanding of the movement patterns are limited but are currently being assessed using satellite telemetry and colour ringing. Movements appear to be more localized than previously expected, with flocks moving in large groups within their subpopulations (e.g. the subpopulation in the Karoo biome) and not mixing throughout the country.
Threats
A combination of grassland habitat loss through land use alteration and agrochemical poisoning has led to the most significant declines in Blue Crane populations. The alteration of large tracts of natural grasslands to commercial afforestation, particularly pine and eucalyptus plantations for paper pulp and timber production, reduce the suitable open grassland habitats required for successful breeding (Johnson 1992, Tarboton 1992). Approximately 1,5 million hectares have already been afforested in South Africa, mainly in the eastern parts of Mpumalanga where the greatest impact has been experienced, with the likelihood of this increasing dramatically in the future, particularly in KwaZulu-Natal and the Eastern Cape Provinces. The documented decline of Blue Cranes has coincided with many reported cases of poisonings from all parts of the country (Tarboton 1992, Vernon et al. 1992, Scott & Scott 1996), although proportionally more from the Western and Eastern Cape Provinces (where large populations of Blue Crane are found and can be expected to occur in crop fields). Poisoning in the past has been through intentional and deliberate poisoning of cranes causing crop damage, the inadvertent poisoning aimed at killing other species causing crop damage, or accidentally through the normal application of agrochemicals to croplands (Filmer & Holtshausen 1992, Allan 1994). Currently, poisoning cases are as a result of farm workers either directly poisoning cranes, or inadvertently poisoning them when baiting grain for gamebirds, for extra food protein.
Another significant threat is the removal of young Blue Crane chicks, prior to fledging, from the wild to be kept as pets, for food, or to sell to bird breeders. In the Karoo, the greatest threat occurs through collisions with the conductors and earthwires of powerlines, both large transmission and smaller distribution powerlines. Other less significant threats occur through domestic dog predation, fences, and chicks drowning in water troughs.
Conservation
Being restricted predominantly to privately-owned farmland, conservation of this species relies on landowner management participation. Within the grassland biome, Blue Crane habitat management needs to be included in future planning of afforestable regions, and people must be discouraged from removing chicks from the wild. A better understanding of overhead powerline collisions is required, which constitutes the most significant threat within the Karoo biome. Throughout the country, but especially in the Overberg / Swartland regions, more responsible use of agrochemicals needs to be encouraged, especially by the farm staff who bait grain to catch birds for food.
Protected areas and IBAs
Steenkampsberg plateau, proposed Grassland Biosphere Reserve, Platberg Karoo Conservancy, KwaZulu-Natal Drakensberg Park, Impendle Nature Reserve, KwaZulu-Natal Mistbelt grasslands, Karoo Nature reserve, Overberg wheatbelt and De Hoop Nature Reserve.
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GREY CROWNED CRANE (Balearica regulorum regulorum)Red Data Category : Vulnerable
Population : 3 500 - 4 500 adults
Key habitats : Wetlands surrounded by natural grassland
Main threats : Habitat loss, poisoning, powerline collisions, chicks captured from wild
Recent evidence of large-scale declines, particularly in KwaZulu-Natal and the Eastern Cape provinces, and the restriction of its range in the Free State and Transkei qualifies the Grey Crowned Crane as Vulnerable. The loss of wetland breeding habitat, direct poisoning of birds in agricultural lands and the removal of chicks from the wild has led to this species' reduction in population size.
Distribution
The Grey Crowned Crane is globally restricted to Africa, with its distribution not having changed much over the last century. The South African population, along with the population in Zimbabwe, Botswana, Mozambique, Namibia and Zambia make up the smaller of the two subspecies, the South African subspecies (Balearica regulorum regulorum). Within South Africa, the Grey Crowned Crane is restricted to the moist eastern, higher rainfall areas of the country, from the Eastern Cape Province, throughout the western parts of KwaZulu-Natal and north-eastern Free State, into the south-eastern regions of Mpumalanga. This species is particularly abundant in higher altitudes such as in the north Eastern Cape and east Griqualand (southern KwaZulu-Natal), KwaZulu-Natal midlands and Wakkerstroom to north-east Free State regions. In the Free State, its breeding range has contracted to the north-east (Geldenhuys 1984), while it no longer breeds in the North West Province (Tarboton 1992)
Figure 3 : Distribution of the Grey Crowned Crane according to the South African Bird Atlas project (Harrison et al. 1997)
Population
The Grey Crowned Crane is the most abundant and culturally significant of the African cranes. The total African population appears to have declined by approximately 15% over the last two decades (Urban 1996), having abandoned certain areas of its former range. Its global population is estimated at between 85 000 - 95 000 individuals (Meine & Archibald 1996), with the majority being represented by the east African subspecies (Balearica regulorum gibbericeps). A recent crane census in South Africa puts the numbers of Grey Crowned Crane at c. 2 800 individuals, although this is probably an underestimate due to the census technique. It comprises three core populations of c. 1 000 birds in the Eastern Cape, including the old Transkei (showing a significant decline since the 1960's of 1 500 birds (Siegfried 1985), just less than 1 400 in KwaZulu-Natal (a population having shown a 55 % decline during the 1980's (Johnson 1992 a)), and almost 350 birds in the north-east Free State / southern Mpumalanga region (McCann 1998).
Ecology
Grey Crowned Cranes require mixed wetland-grassland habitats. They typically nest within or on the edges of permanent or temporary marshes / wetlands (utilizing smaller wetlands than Wattled Cranes). They may also nest in well-vegetated farm dams, where they make their nests among tall, often reedy, wetland vegetation, often of a height so that the nest is sufficiently concealed from terrestrial predators. The breeding season of this species varies depending on the duration and intensity of local dry and wet seasons. In South Africa, the Grey Crowned Crane is a summer breeder, with a peak in egg laying around November / December. Their preferred foraging habitat consists of expanses of short to medium height open grasslands adjacent to wetlands where they feed on grass seeds, insects and other invertebrates. Grey Crowned Cranes also use agricultural lands extensively in which to forage, including pastures, irrigated areas, fallow fields, newly planted cereal crops and harvested fields where they feed on harvest leftovers. The Grey Crowned Crane's generalist feeding strategy has allowed this species to adapt to human settlement and can be found most often in man-modified environments.
Threats
Although this species remains abundant over much of its range, it faces widespread degradation of its historic breeding and feeding habitats. This has occurred particularly through the alteration of wetland habitats, by draining and damming, for intensive farming and the loss of surrounding grassland habitat by agriculture and forestry plantations (Johnson 1992 b, Meine & Archibald 1996). Despite this they have adapted well to the intensified commercial agricultural practices and are often seen feeding in agricultural drylands throughout the year. However, where cranes occur in large numbers in agricultural crops they are threatened by both accidental and deliberate poisoning, through the irresponsible application of agrochemicals. Where crop damage has been reported by cranes, the incidents of shooting and intentional poisoning has increased (Meine & Archibald 1996). Powerlines pose a collision threat to young, inexperienced cranes as well as adult birds in misty low light conditions, while adult birds often get electrocuted on transformer boxes in attempting to roost on these structures. Grey Crowned Crane are also extensively threatened by the removal / catching of young chicks from the wild prior to fledging, either to be eaten, sold or kept as a pet. Many young chicks are also killed every breeding season through the indiscriminate hunting of domestic dogs.
Conservation
The Grey Crowned Crane nests and forages outside of protected areas, with the overriding conservation challenge being the development of sustainable management alternatives for their co-existence within existing land-uses. Through increased awareness and environmental education, community-based habitat (wetland and grassland) conservation programmes need to be developed (e.g. the Wakkerstroom Natural Heritage Association), implementing management recommendations allowing cranes to co-exist in agricultural / human utilized regions. Solutions need to be provided to landowners experiencing crop / animal feed damage by cranes, through methods of preventing cranes eating the crops or establishing crane feeding restaurants during periods of crop sensitivity. Powerline incidents need to be identified and mitigated with standard techniques devised by Eskom. In certain areas, e.g. the Transkei, the cultural significance of the Grey Crowned Crane has afforded it a level of local protection, while general legal protection needs to be strengthened to restrict trade and protect cranes from being removed from the wild.
Protected areas and IBAs
Steenkampsberg plateau, Chrissie pans, proposed Grassland Biosphere reserve, Golden Gate Highlands and Qwaqwa National Parks, Chelmsford Nature reserve, Spioenkop Nature reserve, KwaZulu-Natal Drakensberg Park, Umvoti Vlei, Hlatikulu Nature Reserve, Midmar Nature Reserve, KwaZulu-Natal Mistbelt grasslands, Franklin Vlei, Penny Park, Oribi Gorge Nature Reserve and Vernon Crookes Nature Reserve.
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WATTLED CRANE (Bugeranus carunculatus)Red Data Category : Critically Endangered
Population : 235 individuals
Key habitats : Wetlands surrounded by natural grassland
Main threats : Habitat loss, powerline collisions, burning wetlands, chick capture
South Africa's low Wattled Crane population size of c. 230 individuals within a vastly restricted range, a decline of this population by more than 35 % over the last two decades, and the lowest reproductive potential of all crane species, qualifies this species as Critically Endangered. Within it's much restricted range with two main centres of concentration (KwaZulu-Natal midlands and the Mpumalanga highlands), the aspect of wetland habitat loss on privately-owned land needs to be addressed to secure their survival.
Distribution
The Wattled Crane is restricted to Africa with three main populations being recognised. The main population being found in south-central Africa (Zambia, Botswana, Angola, Zaire, Tanzania and Zimbabwe), while the other two smaller populations being in Ethiopia and South Africa respectively. Historically this species was widespread and formerly occupied all four "old" provinces of South Africa, being common in the eastern Transvaal, Natal, Orange Free State and extending as far south into the western parts of the Cape Province (Somerset West / Caledon) (Brooke & Vernon 1988). It currently occupies a vastly restricted range within the eastern higher rainfall regions of the country, with concentrations in the Mpumalanga Highlands and the midlands to southern parts of KwaZulu-Natal. Small numbers of breeding pairs are also present within the Wakkerstroom region, the Eastern Cape (3 breeding pairs in the north-eastern region) as well as the north-eastern Free State (2 pairs). Wattled Cranes are no longer present within the Western Cape and Swaziland, with very infrequent sightings in Lesotho (Brooke & Vernon 1988).
Figure 2 : Distribution of the Wattled Crane according to the South African Bird Atlas Project (Harrison et al. 1997)
Population
Between 1982-84 and 1998, the South African Wattled Crane population has shown a 36,1 % decline from 360 individuals to the current population size of 230 individuals. The current population shows a population structure ratio of 2.29 : 1 (160 adults : 70 immatures), constituting 80 active breeding pairs and 30,4 % immatures in floater flocks concentrated predominantly within KwaZulu-Natal (McCann et al 1998). The number of active breeding pairs has declined from 144 in 1982 to 80 in 1997, a 44,4 % decline over 15 years (McCann et al 1998). Despite these declines, aerial counts of the KwaZulu-Natal population (constituting almost 80 % of South Africa's population) suggests that it has increased slightly by 14 % over the last 5 years at an average rate of 2,9 % per year (McCann in prep.).
Ecology
The Wattled Crane is the largest and rarest of the six crane species that occur in Africa. The Wattled Crane is a winter breeding wetland-dependent species with a peak in breeding activity between May and August each year, although breeding activity has been recorded in all months of the year (McCann et al 1998). The threat of hail storms and nest flooding have been suggested for the Wattled Cranes tendency to nest within the winter months (Johnson & Barnes 1991). Active breeding pairs are year-round residents of varying size highland marsh wetlands, sometimes using season wetlands opportunistically or as post-breeding dispersal areas. Pairs are strongly territorial and may defend territories several kilometres in size. These territories are highly specialized, comprising permanently inundated wetlands with predominantly sedge-based vegetation (Meine & Archibald 1996). Prolonged disturbance at nest often results in failed clutches. The highly extended breeding period allows individuals unsuccessful in their first attempt to renest the same season (Johnson & Barnes 1991). The Wattled Crane's reproductive rate is low, with the average clutch size being the lowest of any of the cranes (Johnsgard 1983). Pairs may lay either 1 or 2 eggs in a clutch, with the majority of the 2-egg clutches occurring in the KwaZulu-Natal population. In both cases only one chick is raised. Incubation period is the longest of any crane, c. 36 - 40 days. Pairs have an 82 % hatching success rate, with the second egg acting as an "insurance policy" against the first not hatching (McCann et al 1998). The mean breeding success or mean number of chicks fledged per pair per annum is c. 0,67, with 62,2 % fledging success rate, fledging after 110 - 130 days. Juveniles remain with their parents for almost 12 months, after which they are expelled from the breeding territory or are taken to a non-breeding floater flock (essentially only in KwaZulu-Natal). Juveniles obtain full adult plumage after the first year, but only mature and breed for the first time at 8 or 9 years of age (McCann et al 1998).
Threats
Loss and degradation of wetland habitats constitutes the most significant threat to this species, mainly through the loss of wetlands to intensified agriculture, dam construction and industrialization. Grassland areas surrounding suitable breeding wetlands are as important to successful breeding as the wetland itself, with these grassland areas undergoing significant transformation through the planting of exotic timber plantations, a landuse totally incompatible with Wattled Crane survival. In addition, many hundreds of hectares of these grassland habitats are also being converted to intensive agriculture for food production. Management of wetland habitats also constitute a threat, with the frequent burning of wetlands as fire-breaks on farmland and particularly forestry property during the winter months (peak period for Wattled Crane breeding activity), leads to the loss of eggs or young unfledged chicks. Wattled Cranes, especially first-year inexperienced flying birds, are prone to colliding with powerlines, especially 11 and 22 kV rural powerlines, often located within the territories between roosting and feeding sites. Recently, many Wattled Crane individuals / eggs have been removed from the wild for the international bird trade, which can have a significant effect on a small breeding population, and is expected to increase if measures are not taken to control it internationally.
Conservation
This species is reliant on the maintenance of undisturbed, pristine to semi-pristine high altitude wetland and grassland areas within privately-owned farmland. The key to the conservation of Wattled Cranes is to establish mechanisms to encourage private landowners to conserve these birds on their properties. Legislation protecting Wattled Crane habitat needs to be improved locally, while this species is currently included in CITES Appendix 2, with possible suggestions to downgrade it to Appendix 1 to control international trade, a potential threat to the populations in other African countries.
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