5 Dollars - Elizabeth II 4th Portrait, Hamilton Frog

New Zealand Post, rather than the Reserve Bank of New Zealand, issued this piece — a distinction that matters. Coins bearing the Reserve Bank's authority are legal tender in circulation; New Zealand Post issues collector coins under a separate statutory framework, which is why this and similar pieces from the same program were never intended to see a till. The Hamilton's frog series was part of a broader push in the late 2000s to highlight species under active conservation management, with Leiopelma hamiltoni restricted at the time to a single predator-free island sanctuary off the Marlborough Sounds.