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Bucorvus leadbeateri 

Scope: Global
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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Aves Bucerotiformes Bucerotidae

Scientific Name: Bucorvus leadbeateri
Species Authority: (Vigors, 1825)
Common Name(s):
English Southern Ground-hornbill, Southern Ground-Hornbill, Southern Ground Hornbill
French Grand Calao terrestre
Synonym(s):
Bucorvus cafer BirdLife International (1994, 2000, 2004, 2008)
Bucorvus leadbeateri leadbeateri Sibley and Monroe (1990, 1993)
Taxonomic Source(s): del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A. and Fishpool, L.D.C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Lynx Edicions BirdLife International.
Taxonomic Notes: Use of the specific name leadbeateri (Sibley and Monroe, 1990, 1993) is accepted following the reasons given in Browning (1992).

Assessment Information [top]

Red List Category & Criteria: Vulnerable A4bcd ver 3.1
Year Published: 2012
Date Assessed: 2012-05-01
Assessor(s): BirdLife International
Reviewer(s): Taylor, J. & Butchart, S.
Contributor(s): Leonard, P., Roxburgh, L., Tether, R., Thomsett, S., Turner, A. & Tyler, S.
Facilitator/Compiler(s): Butchart, S., Calvert, R., Ekstrom, J., Symes, A.
Justification:
Habitat destruction and persecution are estimated to have caused very rapid population declines in South Africa and there are anecdotal reports that they have caused declines in other range countries. There is a high probability that such threats and subsequent declines will continue into the future, and as such this qualifies as Vulnerable. Should more accurate trend data become available further reassessment may be required in the future.

Previously published Red List assessments:

Geographic Range [top]

Range Description:Bucorvus leadbeateri is found in southern Africa, ranging from southern Kenya and Burundi, south-west to Angola and northern Namibia, and south to Botswana and eastern South Africa. It is described as widespread and fairly common, and the population in South Africa in 1992 has been estimated at c.1,400 mature individuals - perhaps a 50% decline on historical population numbers (Kemp and Webster in litt. 2008). Although data for other range countries is lacking, several threats are also thought to be causing population declines in Kenya (S. Thomsett in litt. 2010), Botswana (S. Tyler in litt. 2010) and Zambia (R. Tether, P. Leonard and L. Roxburgh in litt. 2010), though rates of decline in Zambia are thought to be slower than elsewhere (L. Roxburgh in litt. 2010). In Botswana it is still frequent in the Okavango Delta and Chobe areas, where it occurs at higher densities than it averages in South Africa, but is likely to be declining away from protected areas (S. Tyler in litt. 2012).

Countries occurrence:
Native:
Angola (Angola); Botswana; Burundi; Congo, The Democratic Republic of the; Kenya; Lesotho; Malawi; Mozambique; Namibia; Rwanda; South Africa; Swaziland; Tanzania, United Republic of; Uganda; Zambia; Zimbabwe
Additional data:
Continuing decline in area of occupancy (AOO):Yes
Extreme fluctuations in area of occupancy (AOO):NoEstimated extent of occurrence (EOO) - km2:8670000
Continuing decline in extent of occurrence (EOO):YesExtreme fluctuations in extent of occurrence (EOO):No
Continuing decline in number of locations:Unknown
Extreme fluctuations in the number of locations:No
Upper elevation limit (metres):3000
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:The global population size has not been quantified, but the species is reported to be widespread and common but sparse.

Trend Justification:  An assessment of the species's status in South Africa (Kemp and Webster in litt. 2008) estimated a 20% loss in the area of suitable habitat within the species's national range in the past 15 years. If this figure is used to project declines into the future, this equates to a population decline of 74% over 94 years (three generations). Although declines are also suspected in other range countries (S. Thomsett and S. Tyler in litt. 2010), there are not thought to be significant declines in Zambia, which may be a stronghold of the species (P. Leonard and L. Roxburgh in litt. 2010). As such, and given that data is lacking and that it is difficult to accurately project future declines for such a long-lived species, a decline of 30-49% is projected over 94 years (three generations).

Current Population Trend:Decreasing
Additional data:
Number of mature individuals:UnknownContinuing decline of mature individuals:Yes
Extreme fluctuations:NoPopulation severely fragmented:No
Continuing decline in subpopulations:Unknown
Extreme fluctuations in subpopulations:NoAll individuals in one subpopulation:No

Habitat and Ecology [top]

Habitat and Ecology:Behaviour It lives in groups of 2-8 members, rarely 11, and is a co-operative breeder, with the dominant pair assisted by adult and immature helpers to defend a territory. Laying occurs in large cavities in trees or cliffs, mainly from September to December, with a clutch of 1-3 (usually 2) eggs, although only one survives to fledging (del Hoyo et al. 2001; Kemp and Webster in litt. 2008). One study in South Africa showed that a family group produced on average only one fledgling every nine years, although birds in the Okavango Delta appear to breed more frequently (del Hoyo et al. 2001; S. Tyler in litt. 2010). Habitat It inhabits woodland and savanna, also frequenting grassland adjoining patches of forest up to 3,000 m in parts of its range in eastern Africa. Diet Its diet is mainly made up of arthropods, and, especially during the dry season, snails, frogs and toads, and sometimes larger prey such as snakes, lizards, rats, hares, squirrels or tortoises. It will on occasion feed on carrion, taking scraps and associated insects. Fruits and seeds are also recorded in its diet (del Hoyo et al. 2001).

Systems:Terrestrial; Freshwater
Continuing decline in area, extent and/or quality of habitat:Yes
Generation Length (years):31.3
Movement patterns:Not a Migrant

Threats [top]

Major Threat(s): A major threat to the species is loss of nesting habitat due to clearance for small-scale use, agriculture, and because of fires, and perhaps because of the actions of African elephants Loxodonta africana in Botswana and South Africa (del Hoyo et al. 2001; S. Thomsett, S. Tyler, R. Tether, P. Leonard and L. Roxburgh in litt. 2010; K. Morrison and Y. Friedmann in litt. 2005). Widespread livestock grazing has also lead to the erosion of suitable grassland in Kenya, with perhaps only 10% of suitable habitat remaining in the country (S. Thomsett in litt. 2010). Although cultural beliefs offered some protection in the past in Kenya, recent generations tend not to hold such values, and the species may be directly persecuted as a result (S. Thomsett in litt. 2010). Persecution also occurs directly as the species breaks window panes by attacking its own reflection in glass, indirectly by consuming poisoned bait, and it is sometimes killed as a supersitious token measure against drought (del Hoyo et al. 2001; K. Morrison and Y. Friedmann in litt. 2005). Collisions with powerlines may also be a threat in South Africa (K. Morrison and Y. Friedmann in litt. 2005). Such threats are exacerbated by the slow reproductive rate and maturation, longevity and social structure of the species (S. Thomsett in litt. 2010).

Conservation Actions [top]

Conservation Actions: Conservation Actions Underway
It may still be protected by tribal lore in many areas, and occurs in several reserves and at least seven national parks (del Hoyo et al. 2001). There is extensive conservation work being carried out in South Africa, including a re-introduction programme, research into several different areas (population dynamics, tracking, and the feasibility of supplementary feeding, multiple clutching, group supplementation and artificial nest-site provision), and public awareness campaigns (A. Turner in litt. 2009). From 2000-2008 the Mabula Project attempted 13 soft and hard releases and re- introductions of individuals, and a re-introduced female fledged a chick in 2008 in the Mabula Game Reserve (A. Turner in litt. 2009, 2011).

Conservation Actions Proposed
Conduct population surveys and establish monitoring to assess population trends. Begin awareness campaigns to prevent persecution. Identify key strongholds of the species and prevent further habitat degradation in these areas. Continue to research the effectiveness of artificial nest-sites.


Citation: BirdLife International. 2012. Bucorvus leadbeateri. The IUCN Red List of Threatened Species 2012: e.T22682638A38010935. . Downloaded on 30 August 2016.
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