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The regional population of Blue Crane Anthropoides paradiseus approached but did not satisfy the population-trend criterion for regionally Vulnerable (an estimated, population size reduction of greater than 30% over the past three generations where the reduction or its causes may not be reversible). The species is listed as regionally Near Threatened.
The Blue Crane, which is a near-endemic to South Africa, has the most restricted range of all crane species (Meine and Archibald 1996) with more than 99% of the global population occurring in the region (McCann et al. 2007), with a small population occurring in northern Namibia (Allan 2005). The species is extinct in Swaziland with the last individuals disappearing from Malolotja Nature Reserve in 1995 and Mlilwane Wildlife Sanctuary in 1998 (Monadjem et al. 2003). In South Africa, Blue Cranes occur in three core areas: 1) the eastern grasslands, centred in KwaZulu-Natal, Mpumalanga and north-eastern Free State provinces; 2) the central Karoo in the Northern Cape, southern Free State and Eastern Cape provinces; and 3) the Overberg and Swartland regions of Western Cape Province (McCann et al. 2007).
McCann (2000) estimated the regional population to be c. 21 000 mature individuals. The most recent population estimate for the region is a minimum of 25 500 individuals, with 2 600 of these in the eastern grasslands, 10 800 in the central Karoo and 12 100 in Western Cape (McCann et al. 2007). The confidence in this regional population estimate is medium.
The Blue Crane was listed as regionally Vulnerable in 2000 owing to a population decline of greater than 20% between 1978 and 1998 (McCann 2000). McCann (2000) estimated the population to be c. 21 000 mature individuals in 1988, indicating that the population in 1978 must have been in the order of 23 550 mature individuals. The most recent population estimate for the region is a minimum of 25 500 individuals, with 2 600 of these in the eastern grasslands, 10 800 in the central Karoo and 12 100 in Western Cape (McCann et al. 2007), representing an increase in the regional population of 18%. The cranes in the three core regions have had mixed fortunes, with SABAP2 data showing a continuation of earlier reported declines in the traditional grassland stronghold (McCann 2000). However, national aerial surveys, conducted by the Endangered Wildlife Trust and Ezemvelo KwaZulu-Natal Wildlife, indicate that the population in the Drakensberg regions of KwaZulu-Natal has increased by around 45% over the past decade (KL Morrison unpubl. data).
While the central Karoo population has probably remained stable in this largely untransformed landscape, the Western Cape population has continued to expand and increase as Blue Cranes have adapted to the wheatland/pasture land-use systems (McCann et al. 2007). This suggests an increase in the regional population, although it cannot be discounted that the original estimates were, in fact, underestimates. Notwithstanding, the overall population is presumed to have declined by 15% over the past 39 years (three generations; BirdLife International 2014cb) until further evidence to support on-going stability and increases in local populations is obtained. The confidence in this regional population trend estimate is medium.
Loss of grassland habitat to afforestation, has been a major factor behind the significant decline in the Blue Crane population over the past few decades and was cited as one of the principle reasons for the demise of the species in Swaziland (Monadjem et al. 2003). Habitat loss through development, mining and the expansion of agriculture continues to impact this species. Poisoning also continues to pose a threat, but increased awareness has reduced deliberate poisoning, with most incidents now inadvertent. Collisions with overhead power-lines is currently thought to pose the greatest threat to Blue Cranes, with this bird the most commonly reported species found dead under the expanding power-line network. An estimated 12% of the Overberg population are killed annually by power-lines (Shaw et al. 2010). Continued success of the growing Western Cape population is threatened by any future economic or climate driven changes to farming practices. Other threats to young cranes include drowning in water troughs, disturbance during harvest, predation by dogs, hunting and taking of birds for food (Allan 2005, Monadjem et al. 2003).
Blue Cranes are mainly found on privately-owned farms and rangelands (Young et al. 2003), and so the key to their conservation lies in good relationships between land-owners and conservation agencies to ensure appropriate management of these environments. The African Crane Conservation Programme of the Endangered Wildlife Trust works on many aspects of Blue Crane conservation, including awareness and environmental education for land-owners, local communities and other stakeholders, reducing crane/farmer conflicts, community involvement in sustainable use and conservation of wetlands and grasslands, monitoring of crane populations, the trade in captive cranes, and work with Eskom to reduce power-line collisions. The species is listed under Schedule 2: Specially Protected Wild Animal under the Limpopo Environmental Management (Act No. 7 of 2003).
The evidence to date on the scale of Blue Crane mortality resulting from power-line collisions (Shaw et al. 2010) highlights the urgent need for further research into this threat. So far, line-monitoring has been conducted only in localised areas, and expanding this will help to proactively identify collision hotspots. Experiments to test alternative mitigation solutions for collisions should be set up as soon as possible, as data collection can take several years. A new census of the Blue Crane population, and research into key demographic parameters (including the age of birds killed on power-lines), is crucial to understanding the impacts of collision mortality on populations. Such information will also allow more accurate population modelling to understand other threats, including the impacts of climate change. Further work to gauge the relative seriousness of threats facing the Blue Crane will help to prioritise conservation actions. Continued monitoring of crane populations, habitat conservation, input into EIA processes for new developments (particularly of power-lines, mines and wind farms), and land-owners and the public's awareness on various aspects of crane conservation are also essential.
The Percy FitzPatrick Institute of African Ornithology, in conjunction with the Wildlife and Energy Programme of Endangered Wildlife Trust, are assessing the efficacy of different mitigation devices in reducing collisions on high voltage power-lines in the Karoo, and generating robust collision-rate data in the Karoo and Overberg.