Blue Crane  (Grus paradisea)

Regional Status

IUCN Data (Global)

IUCN 2024. IUCN Red List of Threatened Species. Version 2024-1 (www)

Assessment year: 2021

Assessment Citation

BirdLife International 2021. Anthropoides paradiseus. The IUCN Red List of Threatened Species 2021: e.T22692109A177514877. https://dx.doi.org/10.2305/IUCN.UK.2021-3.RLTS.T22692109A177514877.en. Accessed on 21 November 2024.

Taxonomic notes:

Monotypic.

Geographic range:

Anthropoides paradiseus is near-endemic to South Africa, with a small breeding population also in northern Namibia after rapidly declining in 1980s-1990s. It is now potentially no longer present as a breeding species in Eswatini (Shaw 2015) but small numbers are still observed (eBird 2021), though it is occasionally seen in Lesotho (K. Morrison et al. in litt. 2007).

In South Africa, numbers in the south and south-western Western Cape and KwaZulu-Natal increased around the turn of the 21st century as the species has expanded into agricultural areas (K. Morrison et al. in litt. 2007). However, since 2010 the Western Cape population has begun to decline by 2-3% per year (IUCN SSC Crane Specialist Group, International Crane Foundation, Endangered Wildlife Trust, K. Shaw & P. Ryan in litt. 2020). There has been a 5% reduction in the number of quarter degree grid squares occupied by the species between the two South African Bird Atlas projects (SABAP 1 (1987-1991) and SABAP 2 (2007-2020).  Dramatic declines previously occurred in the latter part of the twentieth century, e.g. of up to 80% in Mpumalanga, KwaZulu-Natal, Free State and Eastern Cape during the 1980s (Barnes 2000).

The increase in the Western Cape, which holds c. 52% of the population, accompanied the conversion of fynbos and renosterveld vegetation to agricultural land (McCann et al. 2007), although adult survival may be relatively low there (van Velden et al. 2017). The population in the central Karoo region, representing c. 29% of the population, is presently thought to be stable, or potentially increasing (Allan, 2005; McCann et al. 2007; Shaw et al., 2015). In the grasslands, formerly the species's stronghold, numbers now represent c.14% of the total population and show significant reductions in reporting rate between SABAP 1 and SABAP 2.

In Namibia, the species continues to persist at low numbers: maximum counts in the 1970s of 138 individuals have dwindled to regular counts of fewer than 35 birds in the past decade (Simmons, 2015; A. Scott and M. Scott in litt., 2018), and a maximum of only 33 in 2019 (Scott et al. 2019; Namibia Crane Working Group 2019).

Small numbers have been recorded in Namaqualand since 2005, a northwest extension of the South African range closer to Namibia (Simmons 2011).

Habitats:

Behaviour This species is a partial migrant which makes local, seasonal movements across elevational gradients (best documented in Natal) (Vernon et al. 1992, Barnes 2000). There is also some movement into the Karoo biome during the winter months (Vernon et al. 1992). However in some areas it appears to be resident or locally nomadic (Hockey et al. 2005). It breeds, usually at high elevations, between August and April, with a distinct peak in November in South Africa and December-March in Namibia (Hockey et al. 2005). Across most of its range, breeding coincides with the summer wet season, although in the Western Cape (which has mainly winter rainfall), they breed in the dry season. It is a territorial, solitary breeder (Hockey et al. 2005), and nesting has been found to occur at a density of 0.57 pairs per square kilometre of appropriate habitat (Barnes 2000). After breeding there is movement to lower altitudes, where the species becomes highly congregatory, occurring in flocks of up to 1,000 (Hockey et al. 2005). It roosts at night, often communally, with roosts being known to comprise hundreds and sometimes thousands of birds (Hockey et al. 2005). Habitat Breeding This species breeds in natural grass- and sedge-dominated habitats, preferring secluded grasslands at high elevations where the vegetation is thick and short (Barnes 2000). Occasionally it will breed in or near wetland areas (Barnes 2000), in pans or on islands in dams (Hockey et al. 2005). Particularly in the Western Cape of South Africa, it also uses lowland agricultural areas, particularly pasture, fallow fields and cereal crop fields as stubble becomes available after harvest (Barnes 2000, Hockey et al. 2005). A few pairs in this area also breed in the coastal dunes (Hockey et al. 2005). Non-breeding During the non-breeding season the species occurs at lower altitudes (Walkinshaw 1973). It inhabits short, dry, natural grasslands, as well as the Karoo and fynbos biomes (Barnes 2000). In the Karoo it is mainly restricted to areas where summer rainfall exceeds 300 mm (Hockey et al. 2005) and where grassland vegetation rather than scrub is dominant (Barnes 2000). In the fynbos it occurs almost exclusively in cultivated habitats, largely avoiding the natural vegetation (Barnes 2000), although this habitat may provide important cover for juveniles (Bidwell et al. 2006). The agricultural habitats that it uses include pastures; croplands, particularly where cereal crops are grown (Barnes 2000), and fallow fields. It is intolerant of intensively grazed and burnt grassland (Hockey et al. 2005). It roosts in shallow wetlands (Barnes 2000, Hockey et al. 2005). Diet This species feeds primarily on plant material including the seeds of sedges and grasses, roots, tubers and small bulbs (del Hoyo et al. 1996, Hockey et al. 2005). It also takes a variety of animals including insects such as locusts and their eggs, grasshoppers, termites and caterpillars, worms, crabs, fish, frogs, reptiles and small mammals (del Hoyo et al. 1996, Hockey et al. 2005). In agricultural areas it feeds on cereal grains such as wheat and maize, and also eats invertebrate crop pests (del Hoyo et al. 1996, Hockey et al. 2005). In agricultural areas, the species is known to feed from livestock troughs, which leads to crane-farmer conflict in a few cases (van Velden, 2016). Breeding site In wetland breeding sites the nest is a simple pad of wetland vegetation (Walkinshaw 1973, Hockey et al. 2005). Elsewhere it may consist of a layer of small stones, dry vegetation or mammal dung  (Walkinshaw 1973, Hockey et al. 2005), or eggs may be laid directly on the grass or on bare ground (Barnes 2000). Preferred nesting sites usually have good all-round visibility (Hockey et al. 2005).

Population:

The most recent published Blue Crane population estimates for South Africa are those of McCann et al. (2007), with a minimum of 25,520 individuals. Of these, the Western Cape held the largest numbers, 12,095 individuals, with 10,822 in the central Karoo and 2,616 in the eastern grasslands, the traditional stronghold (McCann et al. 2007). The disconnected population in northern Namibia is very small, with annual maxima not exceeding 35 in recent years: 32 individuals was the high in 2018, 33 in 2019 (Namibia Crane Working Group 2018, 2019, Scott et al. 2019). The minimum estimate for the global population size is therefore c. 25,550 individuals.

A recent, unpublished, Distance-based survey in the Western Cape suggests that numbers here may be higher than those estimated by McCann et al. (2007), with possibly up to 25,000 birds in the Western Cape alone (C. Craig in litt. via IUCN SSC Crane Specialist Group 2020). This is a very preliminary estimate, assuming presence at equivalent density across all pasture/fallow land in the Western Cape, and would represent a rapid increase in this population up to the recent past. Assuming stability in the other regions, the maximum population size could be c. 38,500 individuals, while if a further assumption is made that the proportions between the three areas have remained the same (i.e. all have increased) then the potential maximum is 45,132 individuals (C. Craig in litt. via IUCN SSC Crane Specialist Group 2020).

The total population size is therefore estimated at 25,550 - 45,132 individuals (here rounded to 25,000 - 46,000 individuals), which is assumed to equate to roughly 17,033 - 30,088 mature individuals, here rounded to 17,000 - 30,000 mature individuals.

While numbers were previously increasing in the Western Cape, recent analysis of driven transect data suggests that this population is now declining by 2-3% annually (IUCN SSC Crane Specialist Group, International Crane Foundation, Endangered Wildlife Trust, K. Shaw & P. Ryan in litt. 2020). If this rate persists, over the next three generations (37.5 years), dependent on the proportion of the whole population that this represents, the future three-generation reduction would be suspected to fall between 24.9-37.6%.

Threats:

The main factors behind its drastic population decline since the 1970s were widespread poisoning on agricultural land (both intentional and accidental [Barnes 2000]) and the commercial afforestation of large tracts of its grassland nesting habitat (Barnes 2000). Poisoning has decreased dramatically over the last few years. Accidental poisoning, however, still occurs occasionally when grain is soaked in agrochemicals for the capture of wildlife for food, although cranes are not usually the target species (K. Morrison et al. in litt. 2007, T. Smith in litt. 2018). Farmers report high levels of crop damage from rodents and geese in the Overberg and Swartland (Mangnall & Crowe, 2001; van Velden, 2016). Poisoned baits are commonly used for controlling rodents, which can result in accidental crane poisoning. Cranes are social birds and poisoning often involves a number of individuals (K. Morrison et al. in litt. 2007). Afforestation is ongoing and large tracts of suitable grassland habitat have been designated for afforestation over the few years following 2007 in the Eastern Cape, KwaZulu-Natal and the Western Cape (K. Morrison et al. in litt. 2007). In the Western Cape, the species is threatened by a change in agricultural crops and increases in the human population in agricultural areas (Bidwell et al. 2006, K. Morrison et al. in litt. 2007, 2017, Shaw et al. 2010). Climate change could force changes in agricultural practices that may be detrimental to the species (K. Morrison et al. in litt. 2007, 2017). It is also uncertain how predicted hotter and drier conditions in the Western Cape will affect breeding cranes over the dry summers. Prolonged dry spells affecting habitat quality not only will directly impact the species, but can also result in competition with domestic stock for habitat at such times (R. Simmons in litt. 1999, K. Morrison et al. in litt. 2007, M. D'Alton in litt. 2018).

Other major threats include collision with power-lines, which is now arguably the major cause of mortality and could have been a major hidden cause before lines were monitored (K. Morrison et al. in litt. 2007, Shaw et al. 2010, Shaw, 2013), entanglement with fences, illegal capture of fledglings (for food and a growing threat from local and international trade [K. Morrison in litt. 2012]), use in local tradition (A. Scott and M. Scott in litt. 2018), predation by domestic dogs and the drowning of chicks in water-troughs (Barnes 2000). In the Overberg, Western Cape, which holds approximately half the global population, modelling gave a conservative estimate that c.12% (95% CI 5-23%) of the Blue Crane population in the study area is killed annually in power-line collisions (Shaw et al. 2010), which exceeds the maximum annual adult mortality rate of 7.5% beyond which a population viability assessment predicts the Western Cape population would be unable to persist (Shaw et al. 2010). Collision rates are also high in the Karoo, but mortality there is likely to be under-reported (Shaw 2013, L. Leeunwner in litt. 2018). Both the Overberg Western Cape and the Karoo have been earmarked by the South African government as priority areas for renewable energy development, ie, wind and solar (Department of Environmental Affairs, 2016). As of yet, wind turbines have resulted in only a small number of casualties of this species, but with predicted increases in the number of wind farms this could become a greater threat to the species (K. Morrison in litt. 2017). The expansion of powerline networks to connect these facilities to the national grid is another threat from renewable energy development. 

Specific threats to the Namibian population include the encroachment of human populations onto the grasslands, and human activities connected to agriculture destroying Blue Crane habitat. Additionally, this species is illegally hunted for use in traditional medicine, and for consumption (Simmons, 2015).

Conservation measures:

Conservation Actions Underway
CITES Appendix II. CMS Appendix II. Conservation measures have expanded in scale since the mid-1980s, including efforts to mitigate power-line collisions, addressing illegal trade, the adoption of stricter legal protection, local and national surveys in South Africa, increasing research on the species's biology and ecology, habitat protection and management programmes (especially on private land, where the majority of its habitat is [Young et al. 2003]), establishment of local conservation organisations, and the development of educational facilities, programmes and publications (Archibald and Meine 1996, Barnes 2000). The introduction of more ecologically sensitive agrochemicals and tighter controls over their use has reduced the number of poisoning events (K. Morrison et al. in litt. 2007). The African Crane Conservation Programme of the International Crane Foundation / Endangered Wildlife Trust Partnership (ICF/EWT) is working in a range of areas to help conserve this species (Shaw 2015). This includes increasing environmental education of stakeholders, community involvement in sustainable use of habitats, reducing conflict with farmers, population monitoring, monitoring of the trade of captive individuals, and working with the power company Eskom to reduce power line collisions (Shaw 2015). EWT/ESKOM research in the Karoo has shown that fitting devices on transmission powerlines to make them more visible to birds is very effective in reducing Blue Crane collisions (Shaw et al. 2021). Prioritising powerline mitigation is key to reducing this threat. A PhD project between the Endangered Wildlife Trust/ International Crane Foundation and FitzPatrick Institute is currently underway, looking to understand the threats to the species in the Western Cape and Karoo, the population trends, and to predict the viability of the species in these regions (C. Craig in litt. 2020). The formation of a Crane Working Group in Namibia has facilitated education, surveys, ringing and protection (R. Simmons in litt. 2007). Future studies in Namibia will assess whether its population is genetically isolated from that in South Africa, and will use transmitters to help study habitat use, their choice of breeding areas and the occurrence of inter-breeding (Simmons et al. 2006).

Conservation Actions Proposed
Prevent conversion of grassland habitat to other land uses and secure sites critical to cranes in the grasslands (K. Morrison et al. in litt. 2007). Monitor the species's population trends through regular surveys, and conduct further work to better understand the relative impact of the different threats facing the species to help plan and prioritise conservation actions (Shaw 2015). Include habitat management in future planning of afforestable regions (Barnes 2000). Encourage more responsible use of agrochemicals (Barnes 2000). Target awareness campaigns at the farming community so as to increase awareness and reduce deliberate poisoning of cranes for food (Barnes 2000, K. Morrison et al. in litt. 2007). Provide effective non-lethal alternatives to prevent damages from geese and rodents, so that farmers do not resort to non-target methods such as poison. Make hazardous power-lines more visible with appropriate devices (Barnes 2000, Shaw et al. 2010, Shaw et al. 2021). Discourage the taking of fledglings from the wild (Barnes 2000). Encourage the retention of a mosaic of pasture and cereal cultivation in the Western Cape (Bidwell et al. 2006). Increase conservation protection of grasslands and wetlands north of Etosha National Park (K. Morrison et al. in litt. 2007) and establish captive breeding populations to support future reintroduction and supplementation efforts. A Biodiversity Management Plan for Species for cranes, as outlined in the National Biodiversity Act (2004) would encourage national support for crane conservation efforts. Actions identified for the Namibian population include researching and monitoring population size, survival and breeding success, and movement. Identify critical areas outside of Etosha National Park that are used by cranes and potentially need conservation attention. Monitor the power lines surrounding the park for collisions and mitigate where necessary (Simmons, 2015).

Rationale:

The total population of the species had largely recovered owing to increases in the Western Cape population offsetting large considerable declines during the second half of the 20th century. However recent data indicates that this population, which comprises the bulk of the global population, commenced a decline in 2010 that has since proceeded at an annual rate of 2-3%: a rate suspected to lead to an overall population reduction of between 25-38% over the three generations from 2010 and into the future. Causes of the recent decline are unknown, although population modelling indicates that only a small decline in estimated recruitment at current low levels of adult survival would lead to rapid declines in the Western Cape population. Previous declines were attributed to direct poisoning, power-line collisions and loss of its grassland breeding habitat owing to afforestation, mining, agriculture and development, any or all of which may once again be impacting the species along with potential capture for trade. It is therefore listed as Vulnerable. If the recent rapid rate of reported declines slows, then the species status will need revision. 

Trend justification:

In South Africa, aerial surveys conducted by the Endangered Wildlife Trust and Ezemvelo KZN Wildlife suggest the population in KwaZulu Natal is increasing steadily, and increased by more than 35% in the decade prior to 2013 (Smith & Craigie 2012). Numbers in the south and south-western Western Cape have increased as the species has expanded into agricultural areas (Hofmeyr, 2012), and a significant increase in densities was recorded through the Coordinated Avifaunal Roadcount (CAR) driven transect surveys between the 1990s and 2019 (Young & Harrison 2020).

However, a separate assessment of the last ten years of the CAR summer surveys (IUCN SSC Crane Specialist Group, International Crane Foundation, Endangered Wildlife Trust, K. Shaw & P. Ryan in litt. 2020) indicates that these increases have reversed; the Overberg population increased by c. 13% annually for 17 years to 2010, but has declined by 4% per year between 2011-2019; the Little Karoo population declined by 2% per year from 2010-2018 (although the highest number of cranes in 19 years of the Little Karoo survey was observed in 2019: CAR data supplied by C. Craig in litt. 2020); and the Swartland population appears to have stabilised after previous increases, only increasing by 0.05% annually between 2007-2017. Great caution is advised when interpreting these trends, as participation in the CAR has declined considerably since 2010 (C. Craig in litt. 2020) and the number of birds appears to be correlated with total distance surveyed.

A model of potential population trajectories indicated that should breeding success reduce, which is conceivable as current values are thought to be high (T. Smith in litt. 2018, K. Morrison in litt. 2020), current rates of adult mortality would be unsustainable (Pettifor et al. unpublished [2007]) and the species would decline again. Given the long generation length of 12.5 years (Bird et al. 2020), and the IUCN SSC Crane Specialist Group, International Crane Foundation, Endangered Wildlife Trust, K. Shaw & P. Ryan in litt. (2020) analysis of recent data, the previously increasing (and suspected to be much larger) Western Cape population is now suspected to be decreasing by 2-3% a year (IUCN SSC Crane Specialist Group, International Crane Foundation, Endangered Wildlife Trust, K. Shaw & P. Ryan in litt. 2020). At this rate, over the next three generations (37.5 years), it is suspected that the future three generation reduction will exceed 30% over the next three generations, although this depends on the proportion of the total population that this part of the population represents, and whether the reduction will continue at this rate for the whole period. At the maximum values provided (C. Craig in litt. [2020] via the IUCN SSC Crane Specialist Group: total population 45,132 individuals, with 25,000 in the Western Cape, 13,900 in the Karoo and 6,000 in the grasslands), then a 2-3% decline in the Western Cape population would result in a decline of 29.3-37.6% over 37.5 years. At the values provided by McCann (2007), the last published estimate, a 2-3% annual decline would result in a 24.9-32% reduction over three generations.

These rates of decline have previously been recorded. In the last quarter of the 20th century the national population was estimated to have fallen by half (Archibald and Meine 1996, Barnes 2000). In the former stronghold of the species, the grasslands, the species has continued to decline slowly throughout, at a rate estimated at 15% over the last three generations (Shaw et al. 2015). A comparison between the first Southern African Bird Atlas Project (1987-1992) and the second (2007-2009), shows that reporting rates declined in 63% of the units surveyed, mainly in the grasslands (Hofmeyr, 2012).

The population in the central Karoo region of South Africa is currently stable or maybe slightly increasing, as the species has adapted to the pasture land use system (Allan 2005, McCann et al. 2007), although it may have increased in the Karoo since the 1980s (Shaw et al. 2015). Eastern Cape Karoo and Eastern Cape Coastal CAR routes indicate stable or slightly increasing trends between 1999 and 2017 (C. Craig in litt. 2020). 

In Namibia the population has been undergoing a steady decline to very low numbers since the 1970s (Simmons 2015, A. Scott and M. Scott in litt. 2018), with recent counts around 32-33 (Namibia Crane Working Group 2018, 2019, Scott et al. 2019).

The drivers of the apparent recent reversal in the trend of the large Western Cape population are uncertain (C. Craig in litt. 2020). The most plausible mechanism is through a reduction in breeding success due to predicted changes in the agricultural landscape with climate or socio-economic change (K. Morrison in litt. 2016), in tandem with estimated high mortality (notable of adults) from infrastructure collisions (especially powerlines; Shaw et al. 2010) and accidental poisoning through the use of poisoned bait to protect crops (T. Smith in litt. 2018, Morrison et al. 2019). Adult survival is estimated to be significantly lower in the Western Cape than in the Karoo, while juvenile and immature survival were higher (van Velden et al. 2017, T. Smith in litt. 2018). If subadult survival/productivity falls, a demographic model for the species predicts there will be a rapid population reduction where adult survival is low (Pettifor et al. unpublished [2007]).

Trade use:

The removal of crane chicks from the wild for domestic and international captive trade is considered a threat in South Africa, with legally kept cranes used to legitimise illegally-obtained individuals by reported that they are the chicks of the legal pair (Morrison et al. 2019).