Assessing the threat of lead ammunition as the probable source of lead poisoning in South Africa’s Gyps vultures.

Lead is a toxic heavy metal that serves no known biological function in any living organism. Its usefulness and malleability as a metal has made it prevalent in many aspects of human society and industry, despite the fact that its harmful effects on human and animal health have been well documented. As obligate scavengers, vultures are especially susceptible to dietary toxins, including lead poisoning. The insidious nature of lead poisoning could lead to a range of difficult-to-diagnose symptoms in birds, ranging in severity from mild to severe and even fatal.

We conducted a nationwide assessment of the levels of lead toxicosis in South Africa’s birds in general, and in vultures in particular. Blood and bone lead samples indicate that a significant proportion of White-backed Vulture (Gyps africanus) and Cape Vulture (G. coprotheres) are displaying elevated lead levels. Non-vulture species, across all tissue types sampled, showed lead levels that are consistent with background exposure, suggesting that certain elements of vulture ecology, such as their scavenging lifestyle, are making them particularly vulnerable to lead poisoning. Of particular concern were the high lead levels found amongst the unfledged chicks of a White-backed Vulture breeding colony near Kimberley.

Our findings point to fragmented lead ammunition as the probable source of the lead poisoning. BirdLife South Africa has taken the first steps in southern Africa to secure Vulture Safe Zones, large tracts of land that would require the use of non-toxic alternatives and be free or reduce the plethora of other pressures currently threatening old world vultures with extinction.


  • LINDA VAN DEN HEEVER, BirdLife South Africa, Johannesburg, South Africa.
  • VINNY NAIDOO, Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa.
  • HANNELINE A. SMIT-ROBINSON, BirdLife South Africa, Johannesburg, South Africa.
  • ANDREW E. MCKECHNIE, Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa.

Date(s) - 17/08/2019
10:30 am - 10:50 am

Merlin Lecture Theatre