Rationale (Changed due to Genuine (recent))

The regional population of the magnificent Secretarybird Sagittarius serpentarius satisfied the criteria for regionally Vulnerable, having undergone a population size reduction of greater than 30% over the past 10 years; this reduction and its causes may not have ceased, is not fully understood and may not be reversible (A4). Trends are based on data from (a) direct observation, (c) a decline in area of occupancy, extent of occurrence and/or quality of habitat, and (d) levels of exploitation. In addition, the population size is estimated to number less than 10 000 mature individuals and is projected to undergo a continuing decline of at least 10% within the next three generations.

Distribution

This species is widespread throughout sub-Saharan Africa (Ferguson-Lees and Christie 2001). In South Africa the species has a broad distribution having been reported in 1 262 or 64.9% of South Africa's Quarter Degree Squares (QDSs) at the time of writing (Hofmeyr et al. 2014) In Swaziland, the species is only regularly encountered in Malolotja National Park and neighbouring areas in the north-east of the country (Monadjem et al. 2003). The species occurs sparsely in Lesotho, where it is found mainly in the western lowlands.

Secretarybirds are not migratory, but are highly mobile. Young birds in particular undertake extensive and often rapid movements (see map), primarily in arid areas, as indicated by fluctuations in numbers (Boshoff and Allan 1997, Herholdt and Anderson 2006). Simmons (2005) reported an individual that moved 1 537 km from its ringing site in the Mpumalanga Lowveld, to northern Namibia.

The density of breeding pairs varies across the range. Tarboton and Allan (1984) reported densities of 0.2-2.0 pairs/100 km2 across the former Transvaal, while Kemp (1995) provides an estimate of 150 km2/pair in Highveld grasslands. A similar estimate of 140 km2/pair was made in the Kgalagadi Transfrontier Park and inter-nest distances of 4.5-15 km suggest comparable densities (Ferguson-Lees and Christie 2001). Actual territory sizes are estimated to be smaller, due to unsuitable habitat or paucity of nest trees between territories, with Kemp (1994) reporting estimates of 70 km2/pair in Highveld grasslands and 45-20 km2/pair in open and more wooded savannahs. The species is well represented in the Important Bird Area network in South Africa, being reported from over 74 IBAs.

Habitat View more ecological information

Population

The global population of the Secretarybird remains unquantified, but is unlikely to be ‘above five figures' (Ferguson-Lees and Christie 2001). Numbers fluctuate widely between years in any one area (Tarboton and Allan 1984), making a regional population estimate extremely difficult. 1 068 pairs were estimated to occur in the former Transvaal (Tarboton and Allan 1984), although this estimate is almost certainly outdated. Kemp et al. (2001) estimated there to be 256±50 mature individuals in Kruger National Park and 128±50 mature individuals in the Kgalagadi Transfrontier Park. Parker (1994) estimated a total of 50 mature individuals in Swaziland, but Monadjem et al. (2003) reduced this to 10 mature individuals. 2 667 birds were recorded in the summer 2013 Coordinated Avifaunal Roadcounts (CAR) while 793 were recorded in winter surveys (Hofmeyr et al. 2014). However, CAR routes excluded large portions of the region, so the number of birds in South Africa could conceivably be between 3 500 and 5 000 mature individuals. The confidence in this estimate is low and requires verification.

Population trend

Ad-hoc records, localised surveys and anecdotal observations indicate apparent declines in many parts of the species' global range and, based on this evidence, the Secretarybird is suspected to be undergoing a rapid decline globally (BirdLife International 2014). Various authors have also reported Secretarybird declines in the region. Boshoff et al. (1983) mentioned that the species had declined in Northern Cape and Western Cape provinces since 1960, while Hockey et al. (1989) mentioned a further decline in the southern Western Cape during the 1980s. Between 2009 and 2012, counts conducted by Ezemvelo KwaZulu-Natal Wildlife have indicated a greater than 50% decline in Secretarybird numbers (Ezemvelo KwaZulu-Natal Wildlife unpubl. data in Hofmeyr et al. 2014). A comparison of SABAP2 reporting rates has indicated a decrease of 73.5% relative to SABAP1 (Hofmeyr et al. 2014); reporting rates decreased in greater than 60% of the QDSs that the species was reported from in either atlas project. This consistent decrease in bird atlas reporting rates for the Secretarybird in a large proportion of QDSs suggests a decrease in abundance across most of its South African range between 1991 and 2007 (Hofmeyr et al. 2014). A 27% decline in AoO from SABAP1 to SABAP2 further reinforces the conclusion that the regional population is in decline. The population trend is therefore deemed negative and ongoing. The rate of decline over the past three generations is greater than 30% although the exact rate of decline is unknown. The confidence in population trend estimate is medium.

Threats

Habitat loss, driven by agriculture and urban development, is the primary threat to this species (Barnes 2000, Hofmeyr et al. 2014). Excessive burning and overgrazing of grasslands for livestock may reduce carrying capacity and availability of prey species (Parker 1994). Bush encroachment, which renders habitat unsuitable for Secretarybirds, has been proposed as the driver behind declines in abundance in Kruger National Park (Hofmeyr et al. 2014) and in Swaziland (Parker 1994). To a smaller extent, trade of the species may be problematic but limited data are available and it uncertain whether the regional population is affected by this activity. Direct hunting and nest-raiding for uses other than trade have also been reported (Monadjem et al. 2003). Indiscriminate poisoning at waterholes is also listed as a potential threat, as is drowning in sheer-walled reservoirs (Anderson et al. 1999). Secretarybirds suffer mortalities through collisions with power-lines (Hartley 1991) and there is a risk in South Africa that wind farms might negatively affect this species in the future (EF Retief pers. obs). Secretarybirds are widely acknowledged as snake-eaters by rural people; ironically, persecution and disturbance of Secretarybirds at the nest, impedes the natural snake control that the birds exert.

Conservation

Underway

A collaborative research project on the species was initiated in 2012 (see Research Priorities and Questions box, below).The species is listed as Endangered in Swaziland and is protected under the Swaziland Game Act (Monadjem et al. 2003). It is listed as Appendix II under CITES.

Proposed

The protection of breeding sites outside of the protected area network using land-use agreements is required. An awareness programme involving land-owners and local communities, which highlights the threats facing this species, is recommended. Further appropriate conservation measures need to be determined as relevant research questions are being answered.

Research

BirdLife South Africa, the Birds of Prey Working Group of the Endangered Wildlife Trust, and the University of the Witwatersrand created a partnership in 2012 to undertake research on the species. This research includes study of the breeding biology and movements of the species to determine details of juvenile dispersal, territory size and habitat use. The research will assist accurate determination of the regional population size and detect threats that might impact upon the species. Key research facets include the following:

* A detailed GIS study of habitat extent and quality for South Africa, linked to rainfall means and variability, to determine key areas and the necessary extent and duration of density and productivity studies that will allow reasonably accurate estimates of population size and trends.

* The rate and extent of the historic and current regional population decreases, and projections for the future.

* The relative densities of the species inside and outside conservation areas.

* The influence of habitat fragmentation and loss over time on the reduction of the range of this species should be assessed. This will include determining appropriate habitat requirements and providing management guidelines to benefit the species.

* Population genetic studies are necessary to estimate the extent of inter-habitat movement within South Africa, and how this relates to meta-population units, sizes and management, including the role of immigration and emigration with neighbouring countries, especially Botswana and Namibia.