Stable isotope analyses of African grey parrots: a forensic isotope approach

Alexander, Jarryd
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Stable isotope analyses have been used to infer diets of organisms, define trophic partitioning, and infer geographic origins of species. It has further been applied to forensic ecology to infer the origins of deceased humans and illegally traded animal (elephant ivory and rhinoceros horn) and plant (cycads, coca, and cannabis) material. However, no research has focused on the isotope analysis of avian material in forensic ecology. African grey parrots Psittacus erithacus are one of the most traded species in the world, with the trade often being illegal, and the origins of confiscated or deceased specimens being unknown. The aim of this study was to determine if stable isotopes (δ 13C, δ 15N, and δ 2H) in African grey parrot feathers could be used to determine the wild or captive origins of birds. African grey parrot feathers (primary, body, and tail) differed isotopically so standardising isotope values of African grey parrot feathers to a single feather type was recommended, to maintain consistent sampling and allow for comparisons to be drawn between different feather types. African grey parrot feathers from unknown origins can be identified as wild or captive using δ 13C and δ 2H values, but not δ 15N values. Known wild and captive feathers possibly differ isotopically from one another because of dietary and location differences. Wild African grey parrots inhabit and feed in isotopically depleted C3 forests compared to captive African grey parrots which are usually fed C4 based foods with more positive isotope values. Wild African grey parrot δ 2H isotope values were the most negative in the central region of their native distribution. The ability to differentiate wild from captive African grey parrots, as well as infer basic origins (East from West Africa) may improve the monitoring of the illegal trade as well as help in tracing illegally traded parrots.
A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of requirements for the degree of Master of Science. Johannesburg, 2016.
Alexander, Jarryd (2016) Stable isotope analyses of African grey parrots: a forensic isotope approach, University of Witwatersrand, Johannesburg, <>