Wattled Crane
Bugeranus carunculatus
Status:	Critically Endangered
Range:	Northeastern Namibia, southwestern South Africa
Area of occupancy:	17,850 km2
Population estimate in Namibia:	300 birds, 10 breeding pairs
Population trend:	Stable/declining
Habitat:	Large permanent wetlands and ephemeral grassy pans
Threats	Wetland degradation, grass burning

Information on this page is from: Simmons RE & Brown CJ 2006. Birds to watch in Namibia: red, rare and endemic species. National Biodiversity Programme, Windhoek, Namibia

Distribution and abundance

Click to see distribution map

This species, the largest and rarest crane in Africa, is found mainly in the huge wetland areas of Zambia, the Democratic Republic of Congo and the Okavango Delta of Botswana. It occurs from the isolated population in Ethiopia (Stattersfield & Capper 2000) through to South Africa, covering 11 countries in Africa. Its range in southern Africa is centred on the Okavango delta where an estimated 1,000 to 3,000 individuals sometimes congregate (Stattersfield & Capper 2000). Botswana ornithologists put this figure lower, at about 800 to 1,400 birds (Mangubuli & Motalaote 1996, Tyler 2001, P Hancock in litt) with influxes due to flooding and burning in the delta and the Makgadikgadi Pans (Herremans et al. 2002, Hancock 2003). A tiny overflow from these populations is found in Namibia's northern swamps, in the floodplains of the northern rivers (Okavango, Kwando, Chobe). A few individuals occur in the Oshana Region north of Etosha NP dugin wetter periods. Other populations are regularly found in the ephemeral pans near Tsumkwe (previously Bushmanland) pans, with Nyae Nyae pan holding up to 95 birds prior to 2001 (Jarvis et al. 2001), and 150 - 275 birds maximum (Hines 1993, Sivhute & Cunningham 2005). Up to 50% of groups in these pans comprise two adults and a grown subadult bird (Hines 1993, Sivhute & Cunningham 2005). This area holds the largest number of Wattled Cranes in Namibia (Simmons et al. 2001). No breeding has ever been recorded however.

The Namibian population is estimated at about 300 birds based on the figures above but this probably fluctuates as birds leave the ephemerally flooded pan systems in northeastern Namibia as they dry out in late winter and flood again with local rains in summer (Hines 1993). There are 13 wetlands where this species is regularly recorded, most from Tsumkwe pans (eight sites) but also from ephemeral lakes north of Etosha at Oponono (average 16 birds) and Oshituntu (six birds: W Versfeld pers obs). The only other areas where it has been regularly recorded in the period 1990-2001 are Mahango Game Reserve (average five birds), the Kwando River where a five km section supports two to three birds, and Sishika Channel, which also supports two to three birds (in Jarvis et al. 2001). In aerial surveys of East Caprivi's Linyanti Swamps, 25 cranes were observed in June 1986 at Nkasa Lupala islands (Williams 1987). The density of birds in the remaining Linyanti Swamps where few islands exist, was low at about 11 birds (Williams 1987). An August 2004 survey of northeastern Namibia has clarified the recent status of Wattled Cranes there (Brown et al. 2004). In total, just 10 pairs of Wattled Cranes were recorded on the floodplains of northeastern Namibia, comprising the following locations: two pairs of Wattled Cranes were recorded in the Mahango Game Park on the floodplains of the Okavango River and eight pairs in East Caprivi. Four of these pairs were in the Mamili section (three pairs on the Kwando floodplains and one pair on the Linyanti), three pairs on the Linyanti northeast of Mamili, and one pair on the Chobe system. There is a clear concentration of Wattled Cranes near the southern end of the Kwando-Linyanti system (Brown et al. 2004). Given that previous aerial surveys of the Linyanti revealed 36 birds in June 1987 and eight birds in August 2004, there is a suggestion of a four-fold decline in a 17 year period. Many other factors might explain this decline other than intrinsic decline in the Namibian population but it remains a worrying trend.

The South African population is estimated at 230 individuals with a decline of 36% over the past two decades (McCann 2000). This decline has been as a result of severe habitat destruction, particularly of grassland habitat surrounding breeding wetland sites, and powerline collisions (McCann 2000). The African population was previously estimated at 13,000 to 15,000 (Stattersfield & Capper 2000), but recent coordinated aerial surveys through the key wetland systems of south-central Africa have shown the population to be approximately 8,000 individuals, this figure reflecting mainly an improved census estimate but also some intrinsic decline of the African population (Beilfuss et al. 2003).

Ecology

Prefers the large low-lying wetlands and swamps in northern Namibia, and ephemerally flooded pans, where the small amphibians and tubers on which they feed can be numerous. This is in contrast to the habitat preferred in South Africa which comprises high altitude, small permanently flooded wetlands (Allan 1997). Elsewhere it feeds on small reptiles, small mammals, insects, grain, tubers and rhizomes (Maclean 1993).

Breeding activity peaks in May to August in South Africa (McCann et al. 1998), but seasons may differ in Namibia where only four records indicated young birds occur in August (two), November (one) and April (one) (Jarvis et al. 2001). Virtually nothing is known of breeding in Namibia despite subadult birds appearing in the flooded Tsumkwe pans each year and breeding records from floodplains in the Kwando, Linyanti, Okavango and Chobe rivers (Williams 1987, Jarvis et al. 2001). Wattled Cranes require shallow flooded wetlands in which they build their large ground nests surrounded by a small open moat. They tolerate no disturbance (Dennis & Tarboton 1993) at these nests. Clutches of one to two eggs are laid (Johnson & Barnes 1991, McCann et al. 1998), and typically only one young survives. The young birds stay with their parents until about one year old, when the adults begin to breed again.

Threats

Because these cranes rear only one young (McCann et al. 1998), and reach sexual maturity as late as eight to nine years old (McCann et al. 1998) their breeding rate and generation time is slower and longer than any other terrestrial bird in Africa. They have been found to have the lowest reproductive rate of any crane species worldwide (Meine & Archibald 1996). Thus their ability to recover from natural disasters or anthropogenic disturbance is very limited. While degradation of wetlands is given as the main reason for Wattled Cranes losing ground in southern Africa (Allan 1997, McCann 2000) the wetlands frequented by cranes in Namibia are either partially protected by conservancies (Nyae Nyae and surrounding pans), remote and rarely visited by humans (Oponono and Oshituntu, north of Etosha) or inaccessible (Linyanti and Chobe Swamps). Thus direct human disturbance is likely to be minimal but the substantial use of fire in these northern regions (Mendelsohn & Roberts 1997), is likely to destroy nests occupied in winter or early spring.

Flow regulation of major rivers is the only other probable threat in Caprivi, as diversion weirs are considered at Divundu on the Okavango River. Increased tourism to tourist destinations such as the Nyae Nyae Pan area may disturb birds there but most areas are inaccessible due to flooding at the time any breeding is likely to occur.

Conservation Status

This species is classified as Critically Endangered because of its very small population of about 300 birds within Namibia. There have been no known or suspected declines, although populations are expected to fluctuate seasonally as adults and their young move in and out of Namibia. This population is probably contiguous with the large Okavango Delta population given the large movements known to be made by this species (McCann et al. 2001), thus fragmentation is unlikely to influence population genetics. The largest concentrations of 95 birds on the Nyae Nyae pans (Jarvis et al. 2001) are recognised but not formally protected by one of Namibia's 21 Important Bird Areas in this pan system (Simmons et al. 2001).

Actions

Understanding the movement of individuals and determining the possible location of a relatively large unknown breeding population in Namibia (numbering tens of pairs), is the highest priority. This could be undertaken with a radio-tracking or satellite tracking study as undertaken in South Africa on Blue Cranes (McCann et al. 2001).

With the largest concentration of Wattled Cranes centred on Nyae Nyae pans, the enhanced protection of this area is a priority, particularly since it may be a nursery area for subadult birds still in the care of the parents, hatched elsewhere in southern Africa. Because of the extended time to sexual maturity in this long-lived species this stage of its life is critical to the long term maintenance of the population. The area should continue to be monitored regularly in the annual wetland counts. A recent (2004) initiative to assist crane conservation in Namibia is the establishment of the Namibia Crane Working Group, funded by the NNF and SIDA. From this a comprehensive Action Plan has emerged which was recently implemented (2005). A regular Crane Newsletter and updates on activities are underway (A & M Scott, pers comm), and include surveys, conservation of critical habitat, a booklet on crane conservation, capacity building activities in each species' main habitat, and crane-related tourism.

References

Allan DG 1997. Wattled Crane In: Harrison JA, Allan DG, Underhill LG, Herremans M, Tree AJ, Parker V & Brown CJ (eds). The Atlas of Southern African Birds. Vol. 1: 312-313. BirdLife South Africa, Johannesburg

Beilfuss R, Bent C, Hancock P, Kamweneshe B, McCann K & Morrison K 2003. Water, wetland and Wattled Cranes: a regional monitoring and conservation programme for southern Africa. Proceedings of the Environmental Monitoring of Tropical and Subtropical Wetlands conference, Maun, Botswana.

Brown CJ, Stander P, Mayes S, Conradie P, Haredoeb M, Singwangwa W & Cilliers A 2004. Status of Wattled Cranes on the floodplains of north-east Namibia: results from an aerial survey during August 2004. Unpublished report Namibia Nature Foundation, Windhoek

Dennis N & Tarboton WR 1993. Waterbirds: birds of southern Africa's wetlands. Struick, Cape Town

Herremans M, Muller M, Allsopp R, Borello WD, Pryce E, Pryce B, Herremans-Tonnoetr D & Bridges D 2003. "Migrant flocks" of Wattled Cranes Bugeranus carunculatus in Botswana. Ostrich 73: 166-180.

Hines CJH 1993. Temporary wetlands of Bushmanland and Kavango, northeast Namibia. Madoqua 18: 57-69.

McCann K 2000. Wattled Crane Grus carunculata In Barnes KN(ed) The Eskom Red data book of birds of South Africa, Lesotho and Swaziland Pp 26-27. Birdlife South Africa.

McCann KI, Wilkins HJ & Morrison K 1998. Population dynamics of the Wattled Crane Grus carunculata in South Africa between 1982 and 1997. In Adams NJ & Slotow RJ (eds) Proc 22nd International Ornithol. Congress, Ostrich 69: 347.

McCann KI 2000. Wattled Crane. In: Barnes KN (ed).The Eskom Red data book of birds of South Africa, Lesotho and Swaziland. Pp26-27 Birdlife South Africa, Johannesburg

McCann KI, Shaw K, Anderson MD & Morrison K 2001. Techniques for determining movement patterns of Blue and Wattled Cranes in South Africa - colour ringing versus satellite telemetry. Ostrich Supplement 15: 104-108

Meine CD & Archibald GW (Eds) 1996. The Cranes - Status Survey and Conservation Action Plan. IUCN, Gland, Switzerland and Cambridge, U.K. 294 pp.

Mendelsohn J & Roberts C 1997. An environmental profile and atlas of Caprivi. Directorate of Environmental Affairs. Gamsberg-MacMillan, Windhoek.

Jarvis A, Robertson AJ, Brown CJ & Simmons RE 2001. Namibian Avifaunal data base. National Biodiversity Programme, Ministry of Environment & Tourism, Windhoek

Simmons RE, Boix-Hinzen C, Barnes K, Jarvis AM & Robertson A 2001. Namibia In: Fishpool LDC, Evans MI (eds). Important Bird Areas of Africa and its islands. Pp 639-660. Birdlife International, Cambridge UK

Sivhute V & Cunningham P 2005. Namibian Crane News 12. Namibian Crane Working group.

Johnson DN & Barnes PR 1991. The breeding biology of the Wattled Crane in Natal. In: Harris J (ed.). Proc of the 1987 International crane workshop. Wisconsin, ICF pp 377-386.

Stattersfield AJ & Capper DR (eds) 2000. Wattled Crane p 166 Threatened Birds of the World. Birdlife International, Cambridge.

Tyler SJ 2001 A Review of Waterbird Counts in Botswana, 1991-2000, Birdlife Botswana, Wetlands International, Gaborone.

Williams J 1987. Wattled Crane survey in Caprivi. Quagga 22-23

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