Justification of Red List Category
This species has been classified as Endangered because recent evidence from across its range suggests that its population is experiencing severe declines, probably owing to habitat degradation, disturbance, hunting and capture for trade.
Although the species occurs across a vast range, surveyed densities suggest that the total population size does not exceed a five-figure number.
Large declines have been reported throughout the species's range, including the Sahel region of Mali, Niger, and Burkino Faso (Thiollay, 2001, R. Buij, unpublished data), Cameroon (Thiollay, 2006), Kenya (Ogada et al. 2020 in prep.), Botswana (Garbett et al,. 2018), Estwatini (Monadiem et al. 2003) and South Africa (Hofmeyr et al. 2014). On the basis of this evidence the species is inferred to be undergoing rapid declines overall.
Sagittarius serpentarius occurs in sub-Saharan Africa, from southern Mauritania, Senegal, The Gambia and northern Guinea eastwards, north of the forest zone, through southern Mali, Burkina Faso, Ghana, Togo, Benin, southern areas of Niger, Chad, Sudan, South Sudan and northern parts of Nigeria, Cameroon and the Central African Republic, to Ethiopia and north-western Somalia, and south through eastern areas of the Democratic Republic of Congo, Uganda, Kenya and Tanzania, to southern Africa, including Angola, Zambia, Malawi, Mozambique, Lesotho, Botswana, Zimbabwe, Namibia, Eswatini and South Africa. It is variably described as common to rare (only 10 pairs or less in Waza-Logone west, Cameroon [J. Brouwer in litt. 2012]) and localised, and is sedentary in some parts of its range and nomadic in others (Ferguson-Lees and Christie 2001).
The species inhabits open landscapes, ranging from open plains and grasslands, to lightly wooded savanna, but is also found in agricultural areas and sub-desert (Ferguson-Lees and Christie 2001), with up to 50% of recorded individuals in the Fynbos biome in winter being found in transformed environments (Hofmeyr et al. 2014). In Kruger National Park, South Africa, reports declined to zero in areas of >20% wood cover (Loftie-Eaton, 2017). It ranges from sea-level to 3,000 m. While it is nomadic, birds living in the moist grassland biome are less likely to be nomadic, but will will travel on average 20-30 km per day while foraging (Kemp & Kemp, 1977; Whitecross et al. 2019).
Breeding occurs throughout the year and the species typically nests in a flat-topped Acacia or other thorny tree, where it constructs a flattened stick structure (Ferguson-Lees and Christie 2001). In Kenya, breeding attempts were observed to be disturbed by long droughts and unfavourable weather conditions (B. Amakobe, in litt. 2020). Juveniles can move a long way after leaving their nest site, but will return to their natal area (Retief and Smit-Robinson 2014; Whitecross et al. 2019). Juvenile males travel further than females, but returned closer to the nest site. Natal home ranges average 1.21 ± 0.34 km2 around the nest, and fledglings travel in an average 2.62 ± 0.37 km straight-line distance from the nest (Whitecross et al. 2019). A 2 year old male was also recorded to have successfully raised two chicks in South Africa (Whitecross et al. 2017). A variety of prey is consumed, with insects forming 86% of the diet (Whitecross et al. 2019). Rodents, other mammals, lizards, snakes, eggs, young birds and amphibians also form part of the diet (Kemp and Kemp 1977; Ferguson-Lees and Christie 2001).
Although the species may benefit from deforestation, such positive effects may be outweighed by the negative impacts of spreading cultivation and urbanisation (Ferguson-Lees and Christie 2001). The excessive burning of grasslands may suppress populations of prey species, whilst the intensive grazing of livestock is also probably degrading otherwise suitable habitat (Baker et al. 2011). The Grassland Biome in South Africa is threatened by the expansion of woody vegetation, which would translate to direct habitat loss and a possible reduction in foraging efficacy (Colyn et al., 2020, in review). In Kenya, suitable habitat is being converted to other land uses, particularly for commercial purposes (B. Amakobe in litt. 2020). Disturbance by humans, probably most often herders, is likely to negatively affect breeding. The species is captured and traded in apparently small numbers; however, it is unknown how many die in captivity and transit. Direct hunting and nest-raiding for other uses and indiscriminate poisoning at waterholes are also potential threats. Exposure to secondary pesticide poisoning is a concern, and birds are also susceptible to negative impacts from collisions with fence lines and electric cables (Whitecross et al. 2019). 94 power-line fatalities have been recorded in 20 years by the Endangered Wildlife Trust (A. Botha in litt. 2020). Large ranging behaviour outside of protected areas increases their risk of injury and fatality (Whitecross et al. 2019). These human-induced threats may compound the effects of severe droughts in some areas (Baker et al. 2011).
Conservation Actions Underway
CITES Appendix II. It occurs in a number of national parks and other protected areas across its large range.
A very large and distinctive terrestrial raptor, which stands c.1.2 m tall (Ferguson-Lees and Christie 2001). It is grey, whitish and black in all plumages, with small bill and head, bare face, relatively long neck, exceptionally long, bare legs, and long graduated tail with greatly elongated central rectrices. It has a distinctive crest of black-tipped spatulate feathers (Ferguson-Lees and Christie 2001).
Text account compilers
Amakobe, B., Baker, N., Botha, A., Brouwer, J., Buechley, E., Butchart, S., Colyn, R., Ekstrom, J., Howes-Whitecross, M., Ogada, D., Reteif, E., Shaw, P., Symes, A., Taylor, J. & Westrip, J.R.S.
BirdLife International (2021) Species factsheet: Sagittarius serpentarius. Downloaded from http://www.birdlife.org on 26/09/2021. Recommended citation for factsheets for more than one species: BirdLife International (2021) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 26/09/2021.