Lead-based ammunition is a threat to the endangered New Zealand Kea (Nestor notabilis)

Abstract

Lead (Pb) poisoning is a significant threat to Aotearoa New Zealand's endangered kea (Nestor notabilis), an avian species important to Māori. Historically, exposure was thought to be from lead-containing building materials; however, recent field observations suggest lead-based ammunition as an additional source. We used stable lead isotopes to investigate the sources of lead to kea. Comparing ²⁰⁷ Pb/²⁰⁶ Pb ratios in kea blood (n = 91) to both ammunition and building materials, we found approximately one-third of exposed kea (blood lead > 10 µg/dL) had lead isotope ratios consistent with exposure to lead-based ammunition. As lead ammunition is still used, including in government-sponsored culling programs, our data indicate an urgent need to shift toward non-lead ammunition use to prevent further poisoning and aid conservation efforts. Collaborating with tangata whenua/Māori guardians, we advocate for immediate policy changes to eliminate lead-based ammunition in kea habitat to safeguard this endangered culturally treasured species from extinction.