REFERENCES
- Mundy , P. J. , Butchart , D. , Ledger , J. A. and Piper , S. E. 1992 . The vultures of Africa Randburg and Halfway House : Acorn Books & Russel Friedman Books: .
- Harrison , J. A. , Allan , D. G. , Underhill , L. G. , Herremans , M. , Tree , A. J. , Parker , V. and Brown , C. J. 1997 . The atlas of southern African birds. Non-passerines. Vol. 1 , Johannesburg : BirdLife South Africa .